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A function generator for a time sequential analogue computer. Stacey, John Sydney 1958

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A FUNCTION GENERATOR FOR A TIME SEQUENTIAL ANALOGUE COMPUTER by JOHN SYDNEY STAGEY B.Sc.,Dunelm, A THESIS SUBMITTED  1951  IN PARTIAL FULFILMENT OF  THE REQUIREMENTS  FOR THE DEGREE OF  MASTER OF APPLIED in  the  SCIENCE  Department of  Electrical  We a c c e p t  this  standards  required  degree of  thesis  Master  Engineering  as  conforming  to  the  from c a n d i d a t e s f o r  the  of A p p l i e d  Members of  The  University  of the  Electrical  of B r i t i s h  April,  Science  1958  Department Engineering  Columbia  ABSTRACT The l a r g e numbers ations in  of  pensive  pieces  system i s  often  of  being very bulky,  apparatus.  required  This  for  functions  t o be  arrangement  generated is  resulted  inflexible  because a  and  ex-  separate generated,,  enables a large  by a minimum of  comput-  number of  equipment.  and s h o u l d p r o v e  Moreover,  accurate  to  Yfo„ is  designed  computer.  T h i s method o f  F(X)  stored  t o be  a single  sampling  is  sampled  system.  The p o s i t i o n  meter) , d e t e r m i n e s  the v a l u e  of P ( X ) .  surface  beam,  value  In t h i s  stored  equipmente  the  are  light  value  photocell  functions  is 1000  and a  c o u l d be g r e a t l y  photoEach  photocell galvano-  to  samples p e r  is  of X b y  function is  arranged  - all  The f l e x i b i l i t y  as  drum.  ( c o n t r o l l e d by a w h i c h the  analogue  functions -  stored  a rotating  u n i t up t o  c a n be made from 15 d i f f e r e n t  extra  of  of X at  from the  necessary.  sequential  a discrete  The f u n c t i o n s  of t h e  the  The o u t p u t  functions  at  i n t u r n by a beam of  sampled.  number of  a time  computation enables  system.  function  of X i f  for  and e a c h sampled  g r a p h s mounted a r o u n d the  little  here  very f l e x i b l e  This unit  values  is  in  often  e a c h f u n c t i o n t o be  The method p r o p o s e d  within  required  c o n c e r n e d w i t h systems s i m u l a t i o n have  function generators  the  functions  at  being  indicate second  different  such t h a t  exceeded  the  with very  In presenting the  this  r e q u i r e m e n t s f o r an  thesis in partial  advanced degree at the  of B r i t i s h Columbia, I agree t h a t it  freely  agree t h a t for  available  the  f o r r e f e r e n c e and  permission for extensive  s c h o l a r l y p u r p o s e s may  D e p a r t m e n t o r by  fulfilment  be  Library  s h a l l make  study.  I  g r a n t e d by  the  copying or p u b l i c a t i o n of t h i s t h e s i s  gain  s h a l l not  Department o f  a l l o w e d w i t h o u t my  Electrical  Date_  April  16,  Columbia,  1958.  Head o f  for  written  Engineering,  The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, C a n a d a .  further thesis my  I t i s understood  that  be  University  copying of t h i s  his representative.  of  financial  permission.  iii TABLE OF CONTENTS  P a  Ke  ABSTRACT  i i  ILLUSTRATIONS  iv-v  ACKNOWLEDGEMENT  vi  INTRODUCTION  1  A GENERAL DESCRIPTION OF THE FUNCTION GENERATOR i) ii) iii)  The Method of R e p r e s e n t i n g i n the Computer  Functions ...»••••  6  The O p e r a t i o n of the F u n c t i o n Generator..........................ft.  7  The T h e o r y of  the  Galvanometer  Response  12  THE OPTICAL SYSTEM  17  THE PHOTOMULTIPLIER S Y S T E M . .  21  THE GALVANOMETER POSITIONING CIRCUIT i) ii) iii)  The F u n c t i o n s of the B l o c k D i a g r a m Components •• The O p e r a t i o n of the G a l v a n o m e t e r Positioning Circuit Circuit Details  23 27 29  THE TEST CIRCUIT i) ii)  Requirements  •••.•••...*»»..»»...<»•.  Circuit Details  46 48  THE RESULTS OF THE GALVANOMETER RESPONSE TESTS  54  CONCLUSIONS i) ii)  An A n a l y s i s  of  Recommendations  t h e Re s u i t s for  Future  ...««».«..  61  Work . . . . .  62  APPENDIX (The K 2 - X P h i l b r i c k O p e r a t i o n a l A m p l i f i e r ) .  65  BIBLIOGRAPHY  67 \  iv  ILLUSTRATIONS  Fig. 1  Page Positions Ch£LUXl@ X S  of  Pulses  i n the  Computer  OO O / O O O O O O 0 O 0 0 O 0 O O O 0  » o o « « » o « « » » » # # o  2  A Typical  F u n c t i o n Photograph  3  Showing G e n e r a t i o n and S y n c h r o n i z a t i o n of F u n c t i o n P u l s e s P Y ^ and P y 2 * • • • • • • • • • • • • • • •  4  Method of M o u n t i n g F u n c t i o n s  5  Method of  6  The Response  7  a. b.  8  9  . . . . . . . . . . . . .  on t h e Drum  S a m p l i n g the F u n c t i o n s of a Damped S y s t e m  9  9 10  . . . . . . . . . . to a  6  10  Unit  Shows a D r i v i n g S i g n a l f o r K=4 . , Shows the R e s u l t i n g System Response  . . .  13 13  The V e c t o r s R e p r e s e n t i n g t h e T r a n s i e n t Response of a Damped S y s t e m t o a Driving Signal . . . . . o . » » . « • . . . . . . . . . . . . . . . .  14  The O p t i c a l  18  System  . . . . . . . . . . . ..,>.. . . . . . . • »  10  The T e s t  *...„...<,  18  11  B l o c k D i a g r a m f o r the G a l v a n o m e t e r Positioning Circuit . . . . . . . . . . . . . . . . < > • « . . • .  26  Waveform C o i n c i d e n c e i n the G a l v a n o m e t e r Positioning Circuit . . . . . . . . . . » « . . . . . . . . . . .  §8  13  The P l T r i g g e r  30  14  The P h a n t a s t r o n U n i t  15  The P2 T r i g g e r  16  The C l i p p i n g  12  Screen With Tapered S l o t  Circuit  Circuit  Circuit,  D i o d e Gate and P u l s e 17  The AX{  C i r c u i t Diagram . . . . . .  Inverter  ..„..<>......... Paraphase  Amplifier  Circuit  32 35  Inverter, ....«>  37 39  V  Fig. 18  Page The G a l v a n o m e t e r D r i v e —- S i m p l i f i e d » g  o  .  .  .  .  .  .  .  Circuit .  .  .  .  .  .  .  .  »».««.  41  49  19  X and P Adder and  Galvanometer  20  The B l o c k D i a g r a m of  21  The T e s t C i r c u i t - M u l t i v i b r a t o r Circuit Diagram.......... ••••*.  the  Test  22  The Gate  Circuit  -  Simplified  23  The Gate Cir  Circuit  Diagram  24  B l o c k Diagram f o r t h e P r o p o s e d Galvanometer P o s i t i o n i n g C i r c u i t  . . .  63  25  Model K 2 - X O p e r a t i o n a l A m p l i f i e r  ...  66  (Test  vi  ACKNOWLEDGEMENT  The  work f o r  Computer P r o j e c t trical The  Department DRB  being  Engineering at  project  is  is  part  sponsored  of the  Analogue  Department  of  Elec-  U n i v e r s i t y of B r i t i s h C o l u m b i a . by t h e  Defence  Research  Board,  of National Defence,  Canada,  u n d e r G r a n t Number  C-9931-02(550-GC).  guidance grantee  this  work was  due to  The  of the  author  is  Company which g r a n t e d continue his  D r . E . V . Bohn,  performed,  and t o  the  University  whose  Noakes,  also  expressed  author  on many  for  occasions  Staff.  i n d e b t e d to t h e  him a s c h o l a r s h i p  studies.  under  D r . P.  Appreciation is  a s s i s t a n c e g i v e n to  o t h e r members  to  are  of the p r o j e c t .  the w i l l i n g  him  thesis  c o n d u c t e d i n the the  Many t h a n k s  by  this  Northern E l e c t r i c i n 1957,  thus  enabling  1 INTRODUCTION In are  systems  required  have  i n the  available  own a d v a n t a g e s considered  versatile  or  i n the  is  for  the  was  required.  requirements  functions  a variety  each h a v i n g  These methods  designed.  generating  of  In t h i s  its  had to  the  be  computer  case,  a l a r g e number o f  of  a  functions  The a c c u r a c y must be to w i t h i n  usual  methods  t o two main c a t e g o r i e s ,  cathode  Electro-mechanical electronic  system  lines  1  methods.  2,  the  p.  in this  t o be d u p l i c a t e d f o r is  (Ref.  approximates  prove v e r y expensive  it  devices.  systems employ s u c h d e v i c e s  photoformer  (Ref.  doubtful  1,  p.  248).  if  315). case  Both these since  the  electro-mechanical  the  of resist-  systems w o u l d  equipment w o u l d  e a c h f u n c t i o n t o be the a c c u r a c y  as  Another  a waveform by a s e r i e s  required l e v e l . Among the  divided  -  or c u r v e d segments u s i n g a n e t w o r k of  a n c e s and d i o d e s  Moreover  these a r e :  (b)  electronic  have  f u n c t i o n generation are  Electronic  r a y tube  straight  of  (a)  The  at  of  functions  These  There are  function generation,  light  of  2%, The  in  for  generator  system  or more)  by some means.  and d i s a d v a n t a g e s .  which t h i s  (15  computation p r o c e s s e s .  t o be g e n e r a t e d  methods  for  s i m u l a t i o n l a r g e numbers  generated.  c o u l d be  maintained  — devices  are  non-linear  2  potentiometers linear  ones  wound t o r e p r e s e n t  operated  functions.  by cams  These f u n c t i o n  cut to  number o f  system b u l k y ,  servos  Another for  function  be s t o r e d edge of  type  of  photographs This  a photo-tube.  servo  when c o u p l e d t o g e t h e r .  The  r e q u i r e d make  the galvanometer.  on 35 mm f i l m  drum r o t a t e s  this  available  F u n c t i o n s can  and mounted a r o u n d the  and i n f o r m a t i o n can be  i n t u r n by a s y s t e m e m p l o y i n g a  ( p o s i t i o n e d by the g a l v a n o m e t e r T h i s a r r a n g e m e n t has  equipment does n o t have  required  d r i v e n and  electromechanical device  from each f u n c t i o n light,  the  and v e r y i n f l e x i b l e .  generation is  a drum.  selected beam o f  as  are  and p o t e n t i o m e t e r s  expensive  f u n c t i o n s , - or  represent  generators  have a p o o r f r e q u e n c y r e s p o n s e large  particular  the  m i r r o r ) and  g r e a t advantage  to be d u p l i c a t e d f o r  each  that  function.  The a c c u r a c y i s  d e t e r m i n e d m a i n l y by the a c c u r a c y w i t h w h i c h  the p h o t o g r a p h s  can be p o s i t i o n e d on t h e d i s c  a c y of d e f i n i n g the  and t h e  l e a d i n g and t r a i l i n g edges  of  the  accurfunction  frames, The f u n c t i o n g e n e r a t o r  t h a t was  by H i l d e b r a n d and F i o r e n t i n o ( R e f s . similar time  3 and 4) employed a  s y s t e m and s c a n n e d the a m p l i t u d e  sequence.  proportional variable.  It  to the  previously designed  of  a l l functions  p r o d u c e d from the p h o t o c e l l f u n c t i o n w i t h time as  The sampled f u n c t i o n was  stored  its  a  in  voltage  independent  in its  own s t o r a g e  «nito  The speed w i t h w h i c h the  functions  a c c u r a t e l y depended on t h e shape of and  t h e b a n d - w i d t h of  system  i n the  necessary a time. finite  to  the  system.  computer has  This  eliminates  b a n d - w i d t h of  the  the  the  individual  Since  t h e n the  been changed,  o b t a i n one d i s c r e t e  c o u l d be  value  signal  so  that  scanned functions storage  it  is  only  of e a c h f u n c t i o n  d i s t o r t i o n due t o  c i r c u i t r y and a l s o  the  at  the  sampling  error. In f2(X) .»».  selected  4),  Q  »»•••  This  and a p h o t o  say),  picked  etc,  surface  drum r o t a t e s  are  stored  system  the  off  is  arranged  function values  photo-  a drum c a l l e d t h e  function  and i n f o r m a t i o n can be  so  that  fj(X ),  o f a beam o f  may  be o b t a i n e d  of Y ,  i n sequence  for  a given value  f2(X )  0  Q  i n t u r n from the photographs  a p a r t i c u l a r value  functions  as  f-^(X),  tube.  for  , , , , , may be  and t h e n ,  (Y Q s a y ) , - f j ( Y 0 ) , from the  of  if  desired,  f2(YQ)  photographs  of  etc,,  the  of Y , To  graphic  the r e q u i r e d f u n c t i o n s  f r o m e a c h f u n c t i o n i n t u r n by means  The (X  design  mounted a r o u n d the  drum ( P i g ,  light  present  f - ^ ( Y ) , t2^)  0  graphs  the  illustrate  representation  a f u n c t i o n of  how s u c h f u n c t i o n s is  2 variables  when d e t e r m i n i n g the p l a t e  convenient, is  involved.  arise  and why p h o t o  c o n s i d e r a c a s e where Such a p r o b l e m o c c u r s  c u r r e n t of a t r i o d e  tube.  4  Here I b be  is  a f u n c t i o n of E  obtained  without  direetly  b  and E c ,  from t h e  Such i n f o r m a t i o n  plate  i n t e r p o l a t i o n - which i s  characteristic  from t h i s  i n t o the  process.  The method w h i c h i t  purely graphical  for  E  is c  methods  it  of  all  of  a small  other  curves  (l). magnitude  the  three  Ib(Eb,  to  find  the  information inaccurate  to  adopt  of  the  group -  here  is  a  terms u s e d  plotted,  photographed  function  drum.  a  one  the  one  graphical curve  combination  functions.  functions, F 2 ,  terms  say  d e v i a t i o n from t h i s  e x p r e s s e d as  = Fx(Eb)  tube,  Then by  G i , G2 c o u l d  + F2(Eb)Gi(Ec)  be  + G2(EC)  +  i n v o l v e d w o u l d depend on t h e  d e v i a t i o n from F i and t h e  of b e t t e r  t h a n Vfo a r e  usually  accuracy  required.  attainable with only  above. been d e t e r m i n e d t h e y w o u l d be  and mounted t o g e t h e r  When t h e  would determine  q u i r e d value  the  variable  When F2, G i , G 2 have  generator  the  group  the Ec)  of  call F^E^).  single  instance  the  proposed  characteristics  The number of  of  Accuracies  of  number of  that  is  being t y p i c a l  possible  For c h o s e n so  plate  T h i s we s h a l l is  feed  one.  c h o s e n as  = 0.  but to  procedure.  computer would be a c l u m s y and  G i v e n the curve  curves  not a convenient  A 3 d i m e n s i o n a l model c o u l d be b u i l t ,  cannot  computer  requires  the v a l u e s  with Ib,  on t h e the  function  o f F ^ and F 2 a t  of E D and t h e n the v a l u e s  of  the  G\ and G 2 a t  re-  the  5  required E , added by the (1).  These  f u n c t i o n v a l u e s w o u l d be m u l t i p l i e d and  computer  i n the  manner  indicated  by  equation  6 A GENERAL DESCRIPTION OF THE FUNCTION GENERATOR  i)  The Method of R e p r e s e n t i n g Reference  fact  that  functions  the at  was  computer a time  made i n t h e requires  from the  computer u s e s a s y s t e m of computations  are  carried  F u n c t i o n s are positioned drum o f to  ten  the  a r o u n d the  channels.  called  the  by a p u l s e  the  (so  i n the  Py p l a c e d  CP1  f u n c t i o n t o be  YI  2a  Y = F(Xi)  of  This  is  the  because  the  p o s i t i o n m o d u l a t i o n whereby  incrementally. i n the  computer  of a m a g n e t i c  is  of  the  by  drum -  drum i s  divided equally are  memory  divided i n 15  parts,  s e p a r a t e d by p u l s e s  computer), between t h e is  the  into  named b e c a u s e t h e y a r e  position  pulses  -  the  A function is clock pulses  repre-  CP^ and  d e t e r m i n e d by the  value  represented.  CP3 (a + Y  1  = 0  Fig.  only discrete values  CP2  I  Channel  to  channels  clock pulses  previous  Computer  section  The s u r f a c e  CP2 i n a c h a n n e l and i t s of  out  stored  These  primary timing pulses sented  pulse  t r a c k s and e a c h t r a c k  i n the  generator,,  surface  computer.  called  Functions  1,  Channel 2 Yo = F (X ) P o s i t i o n s of P u l s e s i n Computer C h a n n e l s  (a P o s ; ' - t i v e quant i t y i n t h i s case) the  7 A function is positive  values.  value  the  of  ceding  is  is  read-write  to  the  c h o s e n as heads  The speed  adjusted  as  measured  and n e g a t i v e channel  is  a distance  shown i n F i g * from t h i s  left.  1.  t o make the  'a'  well  point - positive  F o r c o n v e n i e n c e , the  of  as  zero  from t h e  The v a l u e  pre-  the  to the  right  l e n g t h of  ' 2 a ' „ The drum r o t a t e s a n d by means  i n f o r m a t i o n can be f e d of  as  a c h i e v e d by c o n s i d e r i n g the  f u n c t i o n t o be a t  clock pulse  function  drum.  This  a l l o w e d t o have n e g a t i v e  the drum i s l e n g t h of  i n t o and out  of  fixed very accurately a channel equal  to  of the  and  is  1000 m i c r o -  seconds,, It any v a l u e ator  can now be seen  of X from the  must p r e s e n t  F(X)  t h a t when o b t a i n i n g F ( X )  p h o t o g r a p h of as  a function pulse.  be p o s i t i o n e d a c c u r a t e l y w i t h r e s p e c t clock pulses ii)  i n the  mounted a r o u n d the  of  the  cept  drum i s  computer.  a beam of  function opaque  This  for  on t h e  rotation  the  must  appropriate  of  photographs  a drum as  same s h a f t  shown i n F i g ,  2 transparent  of  functions  i n F i g . 4, as  the  lines  2.  It  - the  The  memory drum  causes each p i c t u r e  once e v e r y r e v o l u t i o n .  photograph i s  except  surface  rotated  light  the  pulse  Function Generator  As p r e v i o u s l y s t a t e d ,  function  to  This  gener-  computer,  The O p e r a t i o n o f the  are  a f u n c t i o n , the  for  to  inter-  A typical is  completely  synchronizing line  8  and t h e f u n c t i o n l i n e . light is  passes  a synchronizing pulse its  f u n c t i o n pulse  clock pulse.  o f P ( X ) a t the v a l u e  The l e n g t h o f time picture  is  of X at  which  to pass  processs  -  t a k e n f o r one c o m p l e t e  the beam o f l i g h t must be  one c h a n n e l - 1000 m i c r o s e c o n d s .  t h e r e a s o n why t h e r e  This  that is  a r e the same number of  pictures  on t h e f u n c t i o n drum as  channels  on t h e memory drum and a l s o why b o t h  drums must be r o t a t e d  synchronizing  there  a t t h e same  ( M o u n t i n g them on t h e same s h a f t  b)  is  sampled,,  Two c o n c l u s i o n s f o l l o w f r o m t h i s  of  The s e c o n d  whose p o s i t i o n i n t h e c h a n n e l  the p h o t o g r a p h was b e i n g  a)  The f i r s t  t h e l e a d i n g edge of w h i c h must be  appropriate  d e t e r m i n e d by t h e v a l u e  eliminates  t o move a c r o s s  The beam i s a galvanometer;, of X d e f l e c t s  holds  i t there u n t i l  of X b e f o r e  the c o i l  accurately  the p i c t u r e  t h e beam 0  moved by a m i r r o r  see F i g , 5 ,  value  a  mechanism)*  the r e q u i r e d value  begins  are  speed,,  The beam o f l i g h t must be p o s i t i o n e d at  of  t h e beam o f  2 p u l s e s a r e o b t a i n e d from t h e p h o t o t u b e .  l i n e d up w i t h the  As e a c h p i c t u r e  attached  to the  coil  A c u r r e n t p r o p o r t i o n a l to the  t h r o u g h the r e q u i r e d a n g l e and  a new X i s  needed.  One c o m p l e t e  channel  9 ^X+  F(X) +  F(X)^  X = 0  Synchronizing Edge Function Edge  Fig.  1 X  2.  A Typical Function  I  0  1 =  Photograph  1  ±  . 1 Channel =1000 usees  1-*-  Phototube Output  "|  Computer Pulses CP1 Fig.  3.  P  y i  Showing  CP2  CP3  Generation  J]  and S y n c h r o n i z i n g  P u l s e s Py^ a n d P y 2  CP4  T2 of  Function  10  F i g . 4.  Method of  Mounting Functions  Photo e l e c t r i c cell Direction o f movement of/picture  on the  Drum  Light source  A x i s of rotation ^-of mirror (and c o i l )  Mirror (and c o i l )  Function  Angle of r o t a t i o n m i r r o r from z e r o position F i g . 5.  Method o f  S a m p l i n g the  Functions  of  11  -1000 time  usees,  -  is  normally allowed for  of the g a l v a n o m e t e r .  cumstances  it  repositioning  However, u n d e r e x c e p t i o n a l  m i g h t be n e c e s s a r y  meter more q u i c k l y  the  than t h i s .  to p o s i t i o n the  Under  these  cir-  galvano-  conditions  if  o n l y a p o r t i o n of e a c h c h a n n e l were u s e d t o accommodate functions, ing  the g a l v a n o m e t e r .  decided to position of  t h e r e m a i n i n g time  investigate  It  is  just  c o u l d be u t i l i z e d for  It  the work of the p r o j e c t  has  a)  is  separate p a r t s : The o p t i c a l  it  towards  that  is  position-  it  was  possible  this  to  end t h a t  most  been d e v o t e d .  c a n now be seen t h a t  comprise three  reason  how q u i c k l y  the g a l v a n o m e t e r .  It  this  for  the  the  function  generator  must  -  system,  i n c l u d i n g the  function  drum, b)  The c i r c u i t r y plier  tube  connected with  to f e e d  function  the p h o t o m u l t i pulses  into  the  computer, c)  The g a l v a n o m e t e r  positioning circuit,  must s u p p l y a d r i v i n g  signal  p o s i t i o n the galvanometer possible  and h o l d  flection  is  it  needed.  as  which  will  quickly  there u n t i l  which  as  a new d e -  12 iii)  The T h e o r y of  the  Galvanometer  Response  The r e s p o n s e t o a s t e p i n p u t of system, city,  where t h e  is  of  the  damping f o r c e  form:  proportional  = e  s  -  (i  s  is  the  angular  6  is  the  steady state  a  is  the  attenuation  P  is  the  damped r e s o n a n t  Fig,  deflection  6 shows a p l o t  In order  to the  velo-  e-^CosBt)  © (t) S S  oscillating  e(t)  Where  is  a damped  after  deflection factor  of  due  the  angular  of © a g a i n s t  to p o s i t i o n  time  t.  to the  step,  system.  velocity.  time.  s u c h a s y s t e m more r a p i d l y a t 0 s s  than is  possible with a step input alone,  acceleration tained  and h o l d  the  the  celerating  final  brings  until  the v e l o c i t y is  5)  i n his  i n the  zero  then a p p l i e d  each  is  input  at at  the  These  of  are  In order  deflection, the  ob-  the  required  t o keep the  re-  to  a large  appropriate  stop de-  moment w h i c h  final  position.  deflection  at  this  required. is  shown i n F i g .  of w h i c h e x c i t e s  s y s t e m of  values  step input than i s  position.  required  to  a new movement  3 step inputs,  response  the  s t e p must be a p p l i e d  The complete of  necessary.  steady state  system a t  A h o l d i n g torque value  are  by a p p l y i n g a v e r y much l a r g e r  quired for  just  and d e c e l e r a t i o n  higher  form 0 s s  work on r a p i d p o s i t i o n i n g  7a.  a separate — at e Cos p t .  servo  It  consists  transient / Smith (Ref.  systems has  pointed  out  13  0,  e(t)  /  time Fig.  6.  The Response  of  to a Unit  +5  r  a Damped System Step  Input  Step 2 -8 U n i t s  Step 1 units  Holding  Signal +1 u n i t  time  Step 3  t  •7-  F i g . 7a.  6  ss  Fig.7b.  0  tx Fig.  t2 7a. b.  Shows a D r i v i n g S i g n a l f o r Shows t h e R e s u l t i n g System  K=4 Response  14  that  the r e s p o n s e s t o  rotating vectors They a r e  these  shrinking vectors. are  p r o p o r t i o n a l to  r o t a t i n g w i t h the  3 steps  c a n be r e p r e s e n t e d  The i n i t i a l the  amplitudes  step inputs  same a n g u l a r  of  by 3 the  p r o d u c i n g them.  v e l o c i t y and  all  —o^t s h r i n k i n g at oii a diagram, to  the  same r a t e  ( e  ).  s e p a r a t e d f r o m e a c h o t h e r by a n g l e s  t h e i r mutual time  displacements.  The  for  (a)  They can t h u s be drawn  requirements  correct  T h a t the a r i t h m e t i c s t e p s must be the  proportional  positioning are:  sum o f  the  three  -  input  steady state d e f l e c t i o n  de-  sired, (b)  That at  the  instant  a p p l i e d the v e c t o r The  Fig«  when the sum of  must be z e r o . f i r s t c o n d i t i o n ensures  8.  third  the  that  three  the  step  is  transients  correct  steady  The V e c t o r s R e p r e s e n t i n g t h e T r a n s i e n t Response of a Damped System t o a D r i v i n g Signal .. ._ ....... .  state d e f l e c t i o n i s obtained.  The second means t h a t when step  3 i s a p p l i e d , the v e l o c i t y of the system i s i s the steady s t a t e d e f l e c t i o n r e q u i r e d . the v e c t o r s drawn a t t h i s values will  of the t r a n s i e n t s  instant  zero and i t s Fig.8  represents  N o t i c e that the  be l a r g e r by f a c t o r s  of e*"^  and e 0 ^ ^ " " ^ ^ r e s p e c t i v e l y .  should be noted t h a t the c o i l  is  galvanometer,  immersed i n f l u i d and thus  the turbulence r e s u l t i n g from the high v e l o c i t i e s is  i n v o l v e d here  l i k e l y to introduce n o n - l i n e a r i t i e s to the system.  r e s u l t of t h i s  initial  represented by the v e c t o r s VI and V2  When the above theory i s a p p l i e d to the it  i t was not p o s s i b l e  As a  to compute a value f o r o(  under the pulsed c o n d i t i o n s used h e r e .  It  is  thought, however,  that the value i t assumes i s probably s m a l l e r than that the l i n e a r case.  position  I f t h i s assumption i s  for  c o r r e c t , then the  -o(t effect  of the e  terms may be neglected when attempting to  p r e d i c t an approximate value of p o s i t i o n i n g time f o r the  gal-  vanometer. Values were computed f o r a d r i v i n g s i g n a l by the v e c t o r s VI = +5,  V2 = - 8 , V3 = +4 - i . e .  pulse amplitude to h o l d i n g voltage s t a t e value of u n i t y .  r a t i o K of 4:1 and a steady  and the e f f e c t s  terms on VI and V2 at time t2 were n e g l e c t e d . -  one with a  The damped resonant frequency of the  galvanometer was taken as 325 c/s  as f o l l o w s :  represented  of the e * ^  The r e s u l t s  were  I6 The t o t a l  p o s i t i o n i n g time  The d u r a t i o n of  the  first  The d u r a t i o n o f t h e For a s i m i l a r  (tj  + t2)  -  450 U s e e s ,  pulse  t^  -  205 U s e e s ,  -  245 U s e e s .  second  signal  pulse  (t2  - t^)  where K = 6, t h e (ti  + t2)  (t2 It vanometer  was d e c i d e d  s h o u l d be  considered  above.  t o a maximum o f the  largest  w i t h o u t damage, mm, a t  the  capable  This,  current  tx)  circuit  to  i t was the  to  -  -  380 u s e e s ,  -  180 n s e e s ,  -  200 H s e e s .  drive  producing signals  160 m i l l i a m p s f o r  250 |i s e e s .  -  o f K was  that  f u n c t i o n drum.  a d j u s t a b l e up t o  the  of  The v a l u e  10:1,  pulse  that  theory gave:  of  the the  be a d j u s t a b l e  considered, galvanometer  form up  would i n v o l v e would a c c e p t  a beam d e f l e c t i o n  The p u l s e d u r a t i o n s  gal-  were  to  of be  16  17  THE OPTICAL SYSTEM The f i n a l y e t been d e s i g n e d ,  v e r s i o n o f the but t e s t s  system d e s c r i b e d here  o b t a i n e d and a l s o  of  galvanometer. The s y s t e m was  9,  to  examine the t r a n s i e n t  o r i g i n a l l y a r r a n g e d as  p r o d u c e d a n a r r o w l i g h t beam.  the  screen which r e p r e s e n t e d  of  through the  the p h o t o t u b e .  milliamps mm. was  the  The image a t  of  A beam o f  the f u n c t i o n s  ture A ,  LI at  the  drum.  galvanometer,  effective  of  the  system.  it  so t h a t  cathode  for  16 16  for  mm. i n d i a good r e s o l u t i o n  of the photographs,  less  focal  l e n g t h from t h e  that  for  the  galvanoaper-  any d e f l e c t i o n  p r o d u c e d a beam p a r a l l e l  T h i s was n e c e s s a r y  but  critical,  o b t a i n e d by p l a c i n g the  Lens L2 was p o s i t i o n e d so  the  o n t o the  a d e f l e c t i o n of  necessary  a l o n g the X a x i s  of  on t o  The beam was  s c r e e n was a b o u t 0 . 5  small width is  its  coil,  by t h e  screen.  A p a r a l l e l beam was lens  shown i n F i g .  position,  s c r e e n and t h e n c e  dimension i n the Y d i r e c t i o n i s  meter  function  t h r o u g h the g a l v a n o m e t e r  light  response  reflected  The s y s t e m was a r r a n g e d  obtained at  meter,  T h i s was  the  the  small aperture A  m i r r o r M , shown i n a d e f l e c t e d  a l l o w e d to pass  not  have been c a r r i e d o u t w i t h  A 30 w a t t p r o j e c t i o n b u l b and t h e  galvanometer  s y s t e m has  t o d e t e r m i n e how s m a l l a beam o f  c a n be the  optical  i n order that  to the l e n s L3  axis  18  Fig.9  Fig.10  The O p t i c a l  System  The T e s t S c r e e n w i t h T a p e r e d  Slot  19  c o u l d reduce from t h e tests, it  the movement o f  when t h e g a l v a n o m e t e r  beam on t h e placed at  cathode.  its  focal  galvanometer quiredto meter.  eliminate  always  all  t h r o u g h the  to  test  the v o l t a g e  the  to the a x i s ,  focal  p o i n t of  the t r a n s i e n t  was  across  change  galvanometer. arity  the  slot  response  the  stationary  to  image  for  to t e s t  obtained but  the t r a n s i e n t  response  -  all  the re-  galvanoslot This  As i t moved of  light  pass-  the d e f l e c t i o n  on the  cathode  deflections  of  lineto  the  beam.  output  it  proved s u f f i c i e n t l y  of  the  galvanometer.  of  had  to e a r l i e r .  l i n e a r i t y between d e f l e c t i o n a n d v o l t a g e  the p h o t o t u b e was  lens  obtain reasonable  T h i s was a c h i e v e d by the method r e f e r r e d fair  in-  re-  was  mm. w i d e .  i n the q u a n t i t y  However, i n o r d e r  remain p e r f e c t l y  of  the  shown i n P i g , 1 0 »  was p r o p o r t i o n a l t o  from t h e p h o t o t u b e ,  the  r e p l a c e d by a r e c t a n g u l a r  slot  system  the  the  o u t p u t from the p h o t o t u b e  beam s c a n n e d a t a p e r e d  i n g through the  the  photocathode.  w h i c h p r o d u c e d a beam 15 mm, h i g h and 0 . 5  screen,  i n the  examined,  Since  be p r o p o r t i o n a l t o t h e d e f l e c t i o n of  The a p e r t u r e  the  Later  movement o f  cathode.  parallel  the same p o i n t o f In order  screen.  r e s p o n s e was b e i n g  l e n g t h f r o m the  one must p a s s  on t o  to  the  photocathode  Hence L3 was a h i g h q u a l i t y l e n s  c i d e n t beam t o L3 i s fracted  l i g h t on t h e  32 mm, maximum o b t a i n e d a t  was f o u n d n e c e s s a r y  i,e,  the  Only from good  20  For  future  tests  s y s t e m s h o u l d be m o d i f i e d .  on the  In order to  p u t from the p h o t o m u l t i p l i e r t h a t flection  of  arrangement it  is  the g a l v a n o m e t e r , of the  optical  suggested t h a t : a)  galvanometer  is  obtain a voltage  p r o p o r t i o n a l to  w i t h o u t a l t e r i n g the  system f o r  function  slot  the  de-  normal  generation,  c o u l d t h e n be u s e d  The n o r m a l beam of and the  on the c a t h o d e would s t i l l the d e f l e c t i o n o f t h e  light  falling  be p r o p o r t i o n a l t o  galvanometer.  The 931-A p h o t o t u b e be r e p l a c e d by a type has  out-  be r e p l a c e d by a l i n e a r l y  graded photographic f i l m .  b)  the  -  The t a p e r e d  light  response,  no g r i d w i r e s  and a l s o has  to  i n t e r r u p t the  a more u n i f o r m c a t h o d e  that  l i g h t beam surface.  21  THE PHOTOMULTIPLIER SYSTEM The r e q u i r e m e n t s are  that  the p u l s e s  themselves  this  part  p r o d u c e d f r o m the  generate p u l s e s which are  with respect  t o the  problem here  is  always  for  clock pulses  to a s c e r t a i n  that  of  the  generator  p h o t o m u l t i p l i e r must accurately  i n the  positioned  computer.  The  the r e s u l t i n g p u l s e s  i n i t i a t e d by t h e same q u a n t i t y of  are  l i g h t f a l l i n g on the  photocathode. The method by w h i c h i t this fed  is  as  follows.  stage.  depends shape o f  which t h i s  on the n a t u r a l the  f r e q u e n c y of  n o t depend on t h e a m p l i t u d e the waveform always  ginning  of t h e  occurs  phototube  this at  be d e t e c t e d  (Rapid r e s t o r a t i o n  the  c a n be a c h i e v e d by means p o i n t c a n be d e t e c t e d low v o l t a g e operate  the  the  pulse.  to  pulse.  It  zero  is  this  point  the  zero  the  does  Hence t h i s  same t i m e a f t e r  be-  cross-  by a s w i t c h i n g c i r c u i t .  t o w i t h i n 0,1 v o l t s  the  the  oscillations.  returns  desirable.  o f a damping d i o d e ) .  switching transistors.  is  t u n e d c i r c u i t and  tuned c i r c u i t i s  a c i r c u i t to produce  phototube  damped  first  o u t p u t and i t  over p o i n t which w i l l of  of  the phototube of  accomplish  The s t e p i n p u t c a u s e s  output voltage  l e a d i n g edge of  to  from the  tuned c i r c u i t to produce a s e r i e s  The time a t  in  proposed  Each output pulse  to a tuned a m p l i f i e r  plate  is  This  The  This  crossover  by a c i r c u i t u s i n g switch w i l l  then  s y n c h r o n i z i n g and f u n c t i o n  22 pulses  f r o m the The  ately  pulses  generator.  p r o d u c e d by t h i s  positioned with respect  function  edges  pulses are will  function  on t h e  to  the  photographs.  a l i g n e d w i t h the  t h e n be a c c u r a t e l y  circuit  accur-  s y n c h r o n i z i n g and When t h e  clock pulses,  positioned  are  synchronizing  the  in their  function  pulses  respective  channels,  are:  The  main l i m i t a t i o n s  a)  The a c c u r a c y  to  the  accuracy  of  this  system  -  function  w i t h w h i c h the  edges  of  the  s y n c h r o n i z i n g and  functions  can be  de-  termined, b)  The a c c u r a c y w i t h w h i c h the X = 0 axies), aligned  c)  on t h e  The r e s o l u t i o n direction.  of a l l  expected  functions  of  the  c a n be  l i g h t beam i n t h e X •  Provided that  to  (the  drum,  no d i s c o n t i n u i t i e s , is  the  centres,  the  the  functions  have  error  from t h i s  cause  be v e r y s m a l l  w i t h a beam 0 . 5 mm. w i d e .  -  less  t h a n lfo -  23  THE GALVANOMETER POSITIONING CIRCUIT The F u n c t i o n s  of  the B l o c k D i a g r a m Components  The B l o c k D i a g r a m of rcuit of  is  this  the  shown i n F i g . 1 1 . diagram are  galvanometer  The f u n c t i o n s  described  of the  .  .  .  applied  PI  Trigger Cct.  to the  output  produces Phantastrons  at  the  trigger  a positive  ' T - ' output  complete  and P 2 - .  _n_  ©  the  duce a +140 put.  the  trigger  input pulse  four  of  c i r c u i t P1+,  these  P2+,  going  IN t e r m i n a l w i l l volts  pulse  The d u r a t i o n of  at  this  Pl-  pro-  the  out-  pulse limits  250 H s e e s . In the P l p h a n t a s t r o n s  extra  output  vided.  terminal  *T' is  The two o u t p u t  identical the  in  trigger  can be a d j u s t e d b&tween t h e 0 to  at  terminal.  A positive  pulse at  pro-  pulse  g o i n g edge a t  There are the  pulse  t e r m i n a l marked ' T + ' j w h i l e  a negative  t  going  input terminal  duces a p o s i t i v e the  components  .  A positive  M  J  ci-  below.  The P l T r i g g e r C i r c u i t  The  positioning  other.  b u t one i s  pro-  signals  isolated  an  are from  24  The P2 T r i g g e r  Circuit  (Ti  This  produces  positive  trigger  trailing  edge o f t h e P l  which are  The C l i p and PPI  circuit  fed  Circuit  pulse  into  from  the  pulses  it.  The f u n c t i o n is  to produce p u l s e s  of  this  which  Clip and PPI  sociated.  The +140  pulses  applied at  are  volt  terminal  and the  opposite  going pulses  at The D i o d e G a t e s  the  output  DGA and DGB  the  input  90  the  output pulses  cdrcuit. is  output i s is  equal  Each i s  the  P+,  the  identi-  own PPI  t o be  gated  IN t e r m i n a l .  that  The  amplitude  input voltage  whose d u r a t i o n i s pulses.  P-.  its  a p u l s e whose to  volts  o p e r a t e d by  from  The v o l t a g e  a p p l i e d to  2  same d u r a t i o n  These g a t e s have circuits.  as-  produces  of  terminals  cal  is  phantastron  circuit  a m p l i t u d e and o f - t h e  circuit  operate  the d i o d e g a t e w i t h w h i c h i t  _TLJ  a  of  the  and gating  25 The" |AX|  Inverter This  cisely  a DC o p e r a t i o n a l  -1.  The P u l s e  amplifier  whose  gain  is  pre-  ^  Adding Also  its  is  Amplifier  a DC o p e r a t i o n a l  input signals  amplifier,  and a m p l i f i e s  w h i c h combines  them w i t h a g a i n  of  both  -4.  Jl_  The X and P A d d e r A n o t h e r DC o p e r a t i o n a l input  signals  together  amplifier  w i t h a g a i n of  ) *  X + P Adder  w h i c h adds  its  two  -I.  - 1  w The G a l v a n o m e t e r These  Drive  circuits  contained within i t s  Circuit are  and the AC D r i v e - i n v e r t e r  driven  feedback  loop.  by the X + P A d d e r and They a r e  arranged  to  are produce  -X  P1+  P2+ Trigger  Edge from  AX  Clip and PPI  Pulse Adding Amp.  X  + P  Adder  P2-  |AX|  Pl Trigger  Drive Invert AC  Invert DC  ro ON  P2+  P2Trigger  Galvanometer Drive Circuit  Clip and PPI  Galvanometer Pl-  F i g . 1 1 , B l o c k Diagram f o r Positioning  the  Galvanometer  Circuit.  27 the p u l s e d and h o l d i n g meter. ii)  Their  currents  arrangement  The O p e r a t i o n o f  is  depicted  this  c i r c u i t is  to the B l o c k Diagram F i g .  Diagram F i g .  12,  step voltage  o f t h e same- s i g n as A X  cuit.  is  If A X  output pulse and t h e n c e operate  will  positive  be  to  Pl pulse,  The o u t p u t f r o m DGA i s Adding A m p l i f i e r , from P1+ t r i g g e r s  fed  of  amplitude fed  fed  is  to  a p p l i e d to  is  equal  the  its  The o u t p u t  — | A X | of  to  and hence t h e  the P2+ p u l s e  pulse the  follows other  inverter.  g a t e DGB, output  is  a pulse  immediately a f t e r the  the  is  then fed  to  them by a f a c t o r  of  the  also  from  the  gate  -}AX|,  is  (Fig,  the G a l v a n o m e t e r D r i v e  ori-  Fig.l2D). Pulse pulse Cir-  inverter a  is  voltage that  12E),  This  applied  Amplifier,  combines  four,  to  c l i p p e d and  one from DGA and i s  Pulse Adding  the  P2+ T r i g g e r  is  this  pulses  i n p u t o f DGA  whose d u r a t i o n i s is  The P u l s e A d d i n g A m p l i f i e r and a m p l i f i e s  12C),  The i n p u t t o  and whose a m p l i t u d e  t e r m i n a l of  the  The  circuit  +JAx| (see  to  P2+ p h a n t a s t r o n v i a t h e  fed  operate  the  t r a i l i n g edge o f  (Fig.  made t o  clipping  same d u r a t i o n as  The r e s u l t i n g P2+ p u l s e , paraphase  triggered.  which produces  the  a  the P l T r i g g e r C i r -  i n t o the  cuit. to  to  one i n p u t t e r m i n a l o f t h e  Meanwhile, the  is  Inverter  a pulse  but i t s  re-  11 and t h e Waveform, C o i n c i d e n c e  is  Voltage  gate produces  described with  seen from the B l o c k Diagram t h a t  12B,  the Paraphase  galvano-  Circuit  t h e n p h a n t a s t r o n P1+ i s  from P l , F i g ,  Gate DGA,  and t h i s ginal  It  the  i n the b l o c k d i a g r a m ,  the G a l v a n o m e t e r P o s i t i o n  The o p e r a t i o n o f ference  as  r e q u i r e d to d e f l e c t  (Fig,  Circuit  its  two i n p u t  12F),  This  pulses  waveform  which provides  the  28 Waveforms  are  drawn f o r  maximum d e f l e c t i o n  ometer f r o m 0 t o X and b a c k a g a i n f r o m X t o ditions  = 15  X =J4X|  Holding Signal  For  galvan-  these  con-  volts.  ^ X = +15V A.  0.  of  4X_=  -15V +15V  X  i +140V B.  Input Pulses DGA PPI  to  P1+  '2-  OV +140V C.  Input Pulses DGB PPI  to P2+  PlOV  D.  O u t p u t P u l s e s from DGA A m p l i t u d e = +JAX  E.  O u t p u t P u l s e s from DGB Amplitude = - | A X I  F.  ..+15V  L_JTT1.-15V  O u t p u t from P u l s e Adding A m p l i f i e r A m p l i t u d e = +4JAXJ  .+60V OV  -60V  G,  Complete Waveform from X ' + P A d d e r which i s fed to the G a l v a n o m e t e r  Fig.  12.  Waveform C o i n c i d e n c e i n G a l v a n o m e t e r Circuit  OV  Positioning  29  c u r r e n t t o move t h e g a l v a n o m e t e r it  to  its  new p o s i t i o n and t o  there. However, we have o n l y d e a l t w i t h the  positive.  When AX i s  negative,  a negative  a s t r o n P l - v i a the P l T r i g g e r C i r c u i t . operates  g a t e DGB v i a i t s  p u t of DGB i s  a P l pulse  trailing  edge of  operates  g a t e DGA.  paraphase  (See F i g . l 2 C ) .  These p u l s e s  a P2 p u l s e  Galvanometer D r i v e  has  The  of a m p l i t u d e  before  of  a r e combined  They a r e  then  and a p p l i e d to  the  Circuit.  The c o m p l e t e the galvanometer  The o u t -  (fig,12E).  from t h e two g a t e s  -X as  phant-  phantastron P2- which  and a m p l i f i e d i n the P u l s e A d d i n g A m p l i f i e r , added to t h e h o l d i n g v o l t a g e  is  It  inverter c i r c u i t .  triggers  DGA p r o d u c e s  c a s e when A X  edge t r i g g e r s  of a m p l i t u d e -|&x| ,  the P l - p u l s e  + JAXJj ( £ i g . l 2 D ) .  sequence  of  o p e r a t i o n s -necessary  t o move  from one p o s i t i o n t o another- and b a c k  again  now been d e s c r i b e d ,  iii)  Circuit  Details  The P l T r i g g e r C i r c u i t This  circuit  j u n c t i o n w i t h the t e s t of  hold  60 v o l t s  voltage meter i s  at  present  circuit.  It  amplitude to t r i g g e r  designed  to operate  requires  a< s t e p v o l t a g e  the p h a n t a s t r o n s .  must be a p p l i e d whenever a new d e f l e c t i o n o f r e q u i r e d and must have the  (X£ - X^) i s vice  is  (Fig.13).  versa.  positive  t h e n the  same s i g n as A X .  step voltage  This the  in  coninput  step galvano-  i.e.  if  must be p o s i t i v e  and  30 The t r i g g e r circuit  R l , C l (of  circuit  comprises  time c o n s t a n t  paraphase  i n v e r t e r - tube V I ,  positive,  i.e.  the  cathode  When AX i s the p l a t e  when AX i s  of V I , t h i s negative  of V I ,  not a f f e c t  the  is  When t h e  f e d t o the  I F i g . 13• Since C l is of VI reduces  an i n p u t pulses  pulse  i n p u t of  is  occurs  phantastron  at P1+.  f e d t o P l - from  from t h e t r i g g e r  •  c i r c u i t s do  The P l T r i g g e r  only lOOpf,,  is  volts  ©  the a m p l i t u d e  of 60 v o l t s  from the  to C l  phantastrons. + 300  grid  step input  going pulse-is  pulses  input  1 m i c r o s e c o n d ) , f o l l o w e d by a  positive, a positive  a positive  Negative  a differentiating  Circuit  parasitic  capacitance  O f the d i f f e r e n t i a t e d  r e q u i r e d t o p r o d u c e the  c a t h o d e and p l a t e  50 v o l t  of V I w h i c h a r e  at  the  signal  and  trigger  necessary  to  31 trigger  the  phantastrons.  Since p o s i t i v e cathode, the  are  required at  V I must be n o r m a l l y c o n d u c t i n g .  300 v o l t s  volts  pulses  at  the  with a bias  The P h a n t a s t r o n C i r c u i t  of  circuit  operates the  of about is  A trigger  140 v o l t s  parsed  cathode  of V 6 »  circuits.  the  (470K)  is  cut off  by t h e r e s i s t o r  volts to  at  suppressor  a b o u t +50  (Note t h a t  has  This  its  pulse  blocking  to  trigger  p r o v i d e d from  the  the  circuits.  in detail  is  as  suppressor  supplies.  voltage  volts,  the s u p p r e s s o r  conduct,  output is  has  pulse  case of the P l p h a n t a -  output pulse  t a k e n t o t h e +300 v o l t s  and h e l d a t  a positive  follows.  held at  about  c h a i n R3 - R6 c o n n e c t e d between t h e  and the -300 v o l t s  by the  trigger  screen g r i d .  In the  circuit  The p h a n t a s t r o n tube V5 (6AS6)  +300 v o l t s  substantially  goes t o t h e P2 t r i g g e r  The o p e r a t i o n o f  -30 v o l t s  are  f o l l o w e r V6 and t h e n c e v i a a  Hence an e x t r a This  s u p p l i e d by R 4 .  from t h e a p p r o p r i a t e  the t r a i l i n g edge of t h e  P2 p h a n t a s t r o n s .  and 70  (Fig,14)  a m p l i t u d e from i t s  the g a t i n g  and  mAs from  the p l a t e  tube V5 w h i c h p r o d u c e s  to a c a t h o d e  d i o d e V4 t o strons  pulse  at  2 volts  The f o u r p h a n t a s t r o n c i r c u i t s identical.  About 4.5  s u p p l y m a i n t a i n s 150 v o l t s cathode,  both plate  The g r i d r e s i s t o r R8  supply. while  the  Hence the p l a t e screen is  A^positive trigger  pulse  v i a C l and d i o d e V 2 , c a u s e s  the  this  at  means a 50 v o l t p u l s e  is  conducting of  35  plate the  input  32  ee  fr-  EH  C/3 <!  < co CO  rH  o  LO  i  he  •H  P»  -P •H  O rl  •rH  o  5 c) o  IH  -p 03  -p a ni PH CD EH  SO  •H  33 terminal After  due to d r o p t h r o u g h d i o d e and s t r a y  a small  initial  fall  t h e n runs down l i n e a r l y a t (see  footnote  voltage  is  positive plate  voltage  time  voltage  this  section).  Pot.  towards  constant  E ^  |  r u n down i s  conducts,  screen which thus  is  the p l a t e  When t h i s  plate  kept at  happens  a  the  a rate determined  300 v o l t s  and the  about  the  The  plate  and t h u s  the  adjustment  trigger  short p o s i t i v e 140 v o l t s  course  microsecond,  When t h i s  the  on the  a m p l i t u d e from the  returned  to produce a p u l s e  of  200  = 240  setting  must be 300  is  -  240  produces  1. 1.2  = 55  a  duration  For i n volts  Hence the -5  to  Hence  m i c r o s e c o n d , the volts.  plate-  current.  volts.  of P o t .  the p l a t e  x 200  the  s c r e e n of V5, the  of  1 tap  has  suppressor  rundown s p e e d  the P o t .  occurs  d r o p s b a c k t o +50  pulse  switched  and r e m a i n s  o v e r the p l a i e  must r u n down t h r o u g h 1.2 of  140 v o l t s  d e t e r m i n e d by t h e a d j u s t m e n t  since  current is  suppressor  s c r e e n a g a i n tikes  the  of which i s  t h e tube  rises  switched off, s i n c e  of  stance,  ends when t h e  d e t e r m i n e d by  rundown e n d s .  The s c r e e n v o l t a g e  of  per microsecond  of w h i c h i s  e x p o n e n t i a l l y at  voltage  1.  volts  pulse  volts  fall  I.  i  there u n t i l  -30  This  o f V3 c a n be v a r i e d from 0 t o  the  current  1.2  the p l a t e  formed by R-9, C3 ( l 6 5 n s e c ) .  When V5 p l a t e from  of  d e t e r m i n e d by P o t .  d u r a t i o n o f the V5 p l a t e of  a rate  5 volts,  c a u g h t by d i o d e V 3 , the p l a t e  returns  by the  to  of about  capacitance).  per  plate voltage  volts.  34 (*5  volts  is  the i n i t i a l  fall  i n plate  volts  when i t  starts  conducting). Referring circuit, tube  to  the r e s i s t o r s  the  other d e t a i l s  R l and R2 t o g e t h e r  V2 p r o v i d e a clamp c i r c u i t  d r i v e n too f a r a bias  for  Footnote  positive  the t r i g g e r  to  of  phantastron  w i t h one h a l f  stop the  by t h e t r i g g e r  the  suppressor  pulse.  of being  R5 p r o v i d e s  diode.  The r a t e o f  run-down i s  1.2  volts  per microsecond f o r the  d e t e r m i n e d from t h e M i l l e r i(t)  circuit  as  below:  plate -  <t)  • / VW\Ar V i  R  (t)  IV*>  For A„ large -o — -  i(t)  Since the i n p u t g r i d i s  =  T  kept approximately at  zero  volts  v0(t) = gJi.dt • i.e.  the r a t e  o f change o f  In the case of volts.  dvo _ i  _ Vj(t) ~W~  dT ~ C ~  the p l a t e  the p h a n t a s t r o n v ^ ( t )  For t h i s R is and C i s  case t h i s  is  305  voltage is  constant  v  ^g^-  at  E^^+, 5  volts,  t h e 470K g r i d r e s i s t o r the  is  500 p f g r i d - p l a t e  R8 capacitor C3.  35 Hence t h e r a t e o f change o f p l a t e  E  bb  +  are  is  volts  per  constant at  :  -  5  B8.C3 When the above v a l u e s  volts  inserted this  second.  gives  1.2  volts  per  microsecond. The F2 T r i g g e r C i r c u i t In the case t a k e n from t h e circuit  is  of  the P l p h a n t a s t r o n s  c a t h o d e of V6 t o  e s s e n t i a l l y a pulse  tube V7 - a 12AT7 t r i o d e . to  the g r i d v i a  CI.  (Fig.15)  limiting  the P2 t r i g g e r inversion  The 140 v o l t s resistance  The o u t p u t from the  plate  the P l p u l s e  is  circuit.  P l pulse  is  R2 and c o u p l i n g  + 300  f e d on condenser  negative  pulse,  volts  CI - . 0 1 _ @  R2 v/WV  This  c i r c u i t comprising  a 200 v o l t  -0  is  CI  1  -  33K  R2 -  47K  Rl  |af  R3 -100K VI -  Fig.  15.  T  h e P2 T r i g g e r  Circuit  12AT7  36  the  t r a i l i n g edge o f w h i c h i s  stron.  It  will  be n o t e d from t h e  that  the  This  differentiates  sary  positive  by r e s i s t o r it  the  trigger  is  R4,  not  Details  This  the  Pl-  o f the  +140  operate volts,  ensures  that  the  operate  circuit  (Fig.16),  They a r e  of  which are  held at the  100 v o l t s  300 v o l t s  supply,  t h e maximum b a c k v o l t a g e  will  is  the  process,  80 v o l t s ) .  are  the  neces-  limited  follower  driv-  operate  seen  g a t e DGA, w h i l e  f e d to  DI and D 2 , t h e  the  which t h i s  and R3  i n series  type  of  keeps  d u r i n g the  the  After  the  volt-  clipping  the p u l s e s  g r i d o f V8 - a  are  diode  more t h a n 250 m i c r o s e c o n d s -  a p p l i e d to  in-  cathodes  R2 (390K)  (Two d i o d e s  maximum l e n g t h of a p h a n t a s t r o n p u l s e . b e e n c l i p p e d t h e y are  are  Condenser C l (0,25|if)  last  be  c l i p p e d t o an a m p l i t u d e  j u n c t i o n o f R2 and R3 c o n s t a n t  w h i c h does n o t  will  combined i n t h e  by r e s i s t o r s  used s i n c e  at  cathode  phantastron pulses  by t h e germanium d i o d e s  age  pf.  g a t e DGB,  100 v o l t s  stand  100  (Fig,16)  P1+ and P 2 - t o g e t h e r  appropriate  across  ( F i g , 14)  t h e P2 p h a n t a s t r o n .  to the B l o c k Diagram i t  of  (220K)  is  g r i d current is  of the 4 p h a n t a s t r o n s  manner,  The  to  of the G a t i n g C i r c u i t s  and P2+ t o g e t h e r  put  phantastron c i r c u i t  overloaded.  outputs  following  P2 p h a n t a -  o u t p u t from V7 and p r o v i d e s  pulse  With reference that  trigger  i n p u t c o n d e n s e r i n t h e P2 p h a n t a s t r o n s  S i n c e the d r i v e t o V7 i s  ing  r e q u i r e d to  12AT7  the have  37 v o  CD Xi O :  <H  *H  <H ft  o  l O i—l ( M O lO . . | O O t-  cd  a  IH;IH  cd  a  CU ^ 2 O O Wm ' N-^ _ O — ' I— po MO CB N O NM ^ . O t - M •H C O C M H M r l H l M O O H H C O  www o o o  ft 3 >> a  XI  M  tad O H H  E-l IO <! H3 CM <i H CO  a  fH H O  rH  h  t 3  T3  H  I  •H  ft a CD  I  i—I IO CD O O  o  r-l CM co o5 oz 05  co  CO  i—i  os 05  PH  I m  rt  t> 0  cd  0)  -P ed cb CD O  •H «  •p u  CD •  rt  M  <D  co  i  cd cd  PH  rt o u  •H  o  w  i  rt  •H  a  rt A  •Hi  .4  to  38  triode plate  tube.  and c a t h o d e  from the from  This  plate  the p l a t e  operate  the  The  n e c t e d as  means  The  that  the  appearing  four diodes equal,  zero.  conductingo thus  pulse  the  output  (i.e.  This  due to  C3,  now f r e e  The 2 p a i r s  follows  the b r i d g e  the re-  thus  at  at  This all  zero  the p l a t e  of V8 b l o c k s to  conduct. gate,  at are  +90  diode D3, S i n c e R9 and p o i n t H, r e -  G, the  input terminal,  c o n d u c t i n g , the  input voltage for  volts.  of V8  S i m u l t a n e o u s l y the  the v o l t a g e  the  of  respectively.  t e r m i n a l of the  to  con-  conditions,  V9 and V10) a r e  appears  cathode  D2-D8  c a r r y i n g c u r r e n t and h o l d  when t h e d i o d e s  be e q u a l  of a c c u r a c y .  v o l t a g e s and i s D5-D8,  at  In f a c t ,  will  diodes  F o r no s i g n a l  condenser  D5-D8 a r e the  six  and -45 v o l t s  zero provided that  put voltage degree  of the  D5-D8  -90 v o l t s  pulses  C3 and C 4 ,  terminal, point H ? is  d i o d e D4 v i a  pulse  mains a t  volts  tube d i o d e s  The o u t p u t  blocks  also  essentially  +45  These  going  (Fig„16)  D3 and D4 a r e  E and F a t  matched  outputs  - negative  cathode,  condensers  The  22K,  90 v o l t p u l s e s  f r o m the  R 9 , R8 and R I O , R7 a r e  RIO a r e  is  gate v i a  consists  When the  volt  are  and p o s i t i v e  diode  i n v e r t e r c i r c u i t whose  R5 and R6 a r e  shown i n the diagram,,  blocked.  it  resistors  and c a t h o d e  germanuim d i o d e s  points  a paraphase  D i o d e Gate C i r c u i t It  sistors  is  positive  to a v e r y or  out-  high  negative  c o n f i g u r a t i o n of t h e 4  diodes  39 When the closes  and the  gating  output v o l t a g e  d e t e r m i n e d by the the  amplifier Since  put at of  parasitic  the v o l t a g e  duration equal  that  the g a t e v i a V 8 .  from t h e g a t e must a l s o be sure t h a t  the b r i d g e  b a l a n c e d when i n t h e potentiometer  Pot.  of  this  resistor  is  zero  ensures  TheJAXl This  at  +|AX|  that  Inverter  of  to  of  is of  fed  diodes  equal  the p h a n t a s t r o n  When A X zero.  is  zero  Thus i t  provided for  pulse  the is  this  and  out-  which pulse  necessary  to  D5-D8  en-  is  The 1000 ohm Adjustment  out when t h e  input  met.  (Fig.17)  a P h i l b r i c k K2 -  X Operational  ci C2  -  7-50  Rl-2  -  100K matched t o 1%  R3 Pot.  17.  rate  t o + | A x J and  output  purpose.  pulse  condition is  Circuit  a  i n t o g a t e DGA, the  amplitude  zero amplitude  c i r c u i t is  Fig.  the  conducting c o n d i t i o n .  this  then  zero at  c i r c u i t formed by t h e d i o d e s  1 is  for  H returns  gate  Ell.  be a p u l s e  to  from V8 e n d , the  capacitances  input r e s i s t o r  point H w i l l  operated  pulses  TheJAXl  1  Inverter  pf.  trimmer  40  Amplifier  c o n n e c t e d as  matched t o w i t h i n 1 $ . will  signalJAxj is  the  input for  is  condenser  adjusted  Resistors  These f i x  R l and R2 a r e  the g a i n a t  thus p r o v i d e an o u t p u t  of  unity.  -JAXJ  ,  100K  The i n p u t  This  voltage  g a t e DGB.  R3 and P o t , while  shown.  1 p r o v i d e the  CI d e c o u p l e s  to e l i m i n a t e  this  bias  for  bias  supply.  any t e n d e n c y f o r  the  the  amplifier, The t r i m m e r C2 output  signal  to  overshoot. The P u l s e It  Combining  can be  Amplifier,  seen from the  the  outputs  the  two 82K matched r e s i s t o r s  terminals feedback  from the  of  eliminates  is  R14 i s  R l l , R12,  amplifier.  s u p p l i e d by R13 and P o t ,  a m p l i f i e r has  to d e a l  i n the  output  amplitude.  +60  volts  a m p l i t u d e w h i c h d r i v e t h e X and P A d d e r . is  l i m i t e d by the a m p l i f i e r  of  the  fied  c i r c u i t is  initially  c i r c u i t diagram P i g . 1 8 ,  to about  o p e r a t i o n of  the  made w i t h r e f e r e n c e In t h i s  the  waveforms. from 0 to  o u t p u t p u l s e s up The  to pulse  8 microseconds.  The X and P Adder and the G a l v a n o m e t e r D r i v i n g The d e s c r i p t i o n of t h e  input  -4,  with input pulses  produces  to  The t r i m m e r C6  volts  time  thus  2,  +15  rise  It  overshoot  Since  f i x e d at  that  fed  These form the  330K t h e g a i n i s  any t e n d e n c y t o  This  g a t e s DGA and DGB a r e  the K 2 - X DC o p e r a t i o n a l  resistor Bias  two d i o d e  c i r c u i t diagram F i g » 1 6 »  Circuit  final  stages  to the  c i r c u i t there  are  simplitwo  41  t u b e s VA and VB c o n n e c t e d i n s e r i e s cathode  resistor  The q u i e s c e n t trolled  cathode  VB b e i n g h e l d a t  these tubes  -300 v o l t s  a s u f f i c i e n t l y negative  A,  at  0 volts.  is  This the  the f e e d b a c k  an a d j u s t a b l e For  by R 1 3 0  G is  25 mAs.  voltage  is  t o keep i t s  con-  g r i d of held  cathode,  point  a c h i e v e d by the f e e d b a c k a c t i o n o f  which i s  the  g r i d of V A .  responsible  for  this  the R3  control.  c o n n e c t e d between g r o u n d and p o i n t A v i a  resistor  RG0  d r i v e f r o m t h e DC a m p l i f i e r ,  f e d t h r o u g h the g a l v a n o m e t e r  Q Fig.  It  supplies.  The g r i d of VA i s  o u t p u t of w h i c h d r i v e s  positive  and c u r r e n t i s  is  resistor  The g a l v a n o m e t e r  is  f o l l o w e r a c t i o n of R15, the  at  DC a m p l i f i e r ,  w i t h t h e V8  R 1 5 , b e t w e e n the +300 and -300 v o l t s  current for  by the  together  18.  to  point A rises  ground.  -  The G a l v a n o m e t e r D r i v e - Simplified  300  For  volts  Circuit  42 small cent  negative current  signals  i n the  g r o u n d and the about  tubes  20 mAs or 80% of i n this  signals,  since  deflection  so t h a t  cannot  be s u p p l i e d  w i t h o u t more q u i e s c e n t  driving  it  followss  are  the  reason  of VB i s  input grid effective  is  is  that  switched  the  holding  deflection  supplied  of  by a DC  c a n be h e l d a t  larger  amplitude  galvanometer  cathode  any  positive  i n the  same  negative  going  follower  action  tubes.  This is  un-  tube VB and the AC a m p l i f i e r  circuit.  They o p e r a t e  d r i v e n n e g a t i v e by the  connected to A v i a  plate  resistance  in potential  the  this  of  full  t h r o u g h the  driven positive  s u p p l y and the v o l t a g e  by  for  Notice  c a n be  care  below  as  -  grid  fall  reversed,.  take  quies-  point A f a l l s  r e q u i r e d by the  why the  i n c l u d e d i n the  When p o i n t A i s the  the  by t h i s  current  the  manner.  to  currents  off  current  r e q u i r e d by the  larger  and i s  is  galvanometer  c a n be s u p p l i e d  However,  desirable  the  that  cut  the  required  Notice also  current  going pulses  pulses  This w i l l  indefinitely in this  The  way.  current  o n l y 16 mAs i s  circuit  to  completely,  the q u i e s c e n t  manner.  galvanometer.  driving  sufficient  galvanometer  linearly  the  not  feedback  at  of the  by the AC a m p l i f i e r C2 & R 6 ) .  point A is of V A .  DC a m p l i f i e r .  (whose  This reduces  of V B , more c u r r e n t  on the g r i d  DC a m p l i f i e r ,  a l l o w e d to  flows  is  Since  large  the  from  follow  This f a l l  the the  the  controlled pulsed  +300  •300  volts  volts  Fig.  19.  CI C2-6 C7  -  C8  -  Rl-3 R4 R5 R6-8 R9 RIO Rll R12 R13 R14-15  --  Pot, Pot.  1 2  ---  10K IK  V11A-B V12-15  ---  6AN8 : 12AU7  .Oluf .1 [it 25 (if 25 V . D . C . 7-50 p f . 33K Vfo 1 Meg 100K 2W 100K 270 ohms 22K 1 ¥ 330K 47K 2W 330K 470 ohms 1W  X + P A d d e r and G a l v a n o m e t e r Circuit  Drive  44  currents  are  coupling  c a n be s a t i s f a c t o r i l y  of  the  required for  o n l y 250 m i c r o s e c o n d s  amplifier  which  is  Amplifier,  are  point A .  of  the v a r i a b l e  - X and the  The waveforms resistor  a particular  drive  The a c t u a l Here i t  is  triodes  V14, V15.  resistor  R5,  supply,  volts  d r i v e as  well  t u b e s V12 and V 1 3 .  the  100.  is  inputs,  Pulse appear  Adjustment  galvanometer  current  the  c i r c u i t are  is is  this  that  These a r e  each 2  V 1 2 , V13 and  purpose.  s u p p l i e d by R4 and P o t . output  this  of  the K 2 - X to  amplifier w i l l 15 v o l t s  give  bias  K2-X s p e c i f i c a t i o n s t is  in fact  a Philbrick Operational  s u p p l y the  (See  shown i n F i g .  1.  The  the +300  the + 75  r e q u i r e d by the  page  tube V l l - a 6AN8.  65.) The  pentode  a c o n v e n t i o n a l RC c o u p l e d s t a g e w i t h a n o m i n a l  The t r i o d e  output  of  used for  Bias  as  the  12G.  t u b e s VA and VB a r e  The AC a m p l i f i e r section  change  connected i n p a r a l l e d .  ensures  -1 and  shown i n F i g .  c o n n e c t e d from the  volts  two  voltage.  seen t h a t  type K 2 - X .  Its  o u t p u t f r o m the  w i t h a g a i n of  RG w i l l  details  12AU7's a r e  Amplifier  pulse  are  The X and P Adder  of  part  d e t e r m i n e d by the DC  the X and P A d d e r .  added t o g e t h e r  at  double  point A is  in fact  the h o l d i n g v o l t a g e  19.  employed i n the VB d r i v e  circuito The waveform a t  for  or l e s s , AC  of  section  the a m p l i f i e r .  is  a cathode It  is  follower  w i t h i n the  gain  connected  feedback  loop  to  45  of  the  cathode ary  amplifier follower  to d e a l  large drive  w h i c h has  a closed  output  this  w i t h the  of  grid  amplitudes.  loop gain  s t a g e was  current  of  -1.  f o u n d to be  The necess-  drawn by t u b e s V 1 3 , V14 on  46 THE TEST CIRCUIT i)  Requirements The s i g n a l s  r e q u i r e d to  p o s i t i o n i n g c i r c u i t are  as  follows?  The change  i n h o l d i n g v o l t a g e |AX|.  c)  A pulse  the  of  was d e c i d e d t o  s i m p l i f i e d the  same s i g n as £ X t o  value  is  microseconds. separate  response  now t h e  of  same f o r  the  galvanometer.  that  the  response  the  of the  for  galvano0.  any,  b o t h outward  galvanometer  a c o m p a r i t i v e l y l o n g time  p o s i t i o n i n g movement,  between movements  the  of  c o u l d be examined f o r  ii)  test  from 0 t o X and b a c k a g a i n f r o m X t o  of X , | A X |  In order  operate  circuit.  c i r c u i t r y required i n that  and i n w a r d movements  initial  =  b)  deflections  particular  galvanometer  The h o l d i n g v o l t a g e - X ,  It  This  the  a)  the P l t r i g g e r  meter f o r  operate  after  its  i t was  required that  the  time  s h o u l d be v a r i a b l e  between 1,000  and  10,000  These  times  c o r r e s p o n d to  movements p e r s e c o n d  100 and  1,000  respectively.  Method of O p e r a t i o n The b l o c k d i a g r a m of t h e  Pig.20.  Prom t h i s  generator stable  is  used  it to  can be  seen  d r i v e the  m u l t i v i b r a t o r w h i c h has  test that  circuit.  c i r c u i t is  shown i n  a s q u a r e wave It  a restoration  triggers time  of  signal a monoabout  47 3300 m i c r o s e c o n d s . a s q u a r e wave the  F o r an i n p u t f r e q u e n c y  output  multivibrator.  Firstly  it  secondly  operates  the  a positive  are as  arranged the  For  to be -J4x|  and t h u s voltage  Signal Gen.  the  the  is  two  150  c/s,  obtained  from  functions.  Pl trigger  circuit  T h i s g a t e has  ( i n the  test  The o u t p u t  and  another  c i r c u i t + |z\X  pulses  i n amplitude  conditions,  f r o m the  -X i n the d e f l e c t i o n  _nj~L  the  about  and of  from the the  same  gate duration  pulses.  test  output  performs  circuit.  + Ax| .  DC v o l t a g e ) .  multivibrator  amplitude  input for  a gate  input v o l t a g e which i s is  120 v o l t s  This output  supplies  it  of  of  gate  s i n c e ZIX = X t h e n -]Ax| = -X is  used  the  holding  circuit.  ~UIT  to P l  M.V<  for  Trigger  The h o l d i n g -X,0  <3>  voltage  Gate +|Z\x| t o D i o d e  Gate  • |«|  Fig,  20.  The B l o c k Diagram of  the  Test  Circuit  48  Circuit  Details The m u l t i v i b r a t o r P i g .  21,  The tube V2 - a 12AT7 d o u b l e as  a monostable m u l t i v i b r a t o r .  pulses  to  the  tube V2 i s  IN t e r m i n a l  a series  3300 m i c r o s e c o n d s pulses  seconds  is  to  fed  plate  circuit  plate  of V3B are  of  the  120 v o l t s  applied to  the  positive  gate  amplitude  between  these  repetition  c a n be r e d u c e d  rate to  negative  circuit,  so  of  of  Pl trigger  in-  micropulses  a cathode  output  IN t e r m i n a l  1000  the  of  multivibrator  to a v o i d  and,  of  going  the  multivibrator.  the  from  interval  i n amplitude  of  positive  each  The n e g a t i v e  input  from  pulses,  necessary  to the  connected  The o u t p u t  c i r c u i t V3B v i a  is  is  going  However,  t h o s e from the  they are  23 and a l s o  desired.  tube V 2 B .  same d u r a t i o n as terminal  interval  follower  50 v o l t s  circuit.  the  -  triggered  The time  an i n v e r t e r  The c a t h o d e  the  by c h a n g i n g  operate  V3A.  Fig.  duration.  if  to  of  200 v o l t  This  or l o w e r  required  signal  of  can be v a r i e d  s q u a r e wave.  are  is  d e r i v e d from a s q u a r e wave of  applied  put  It  triode  follower  loading pulses  the  from  course,  the  have  the  Prom the  output  the  circuit  gate  circuit  Fig.  13. The d u r a t i o n as  follows:  the  multivibrator  pulses  is  determined  -  Since restoration  of  time  R8 i s for  connected the  to  the  +300 v o l t s  monostable m u l t i v i b r a t o r  supply, is  given  the  +300  volts  Output  to P l T r i g g e r  Output t o the g a t e circuit  vO  R3  -300  volts  F i g . 2 1 . The T e s t  Rl R2 R3 R4 R5-6 R7 R8-9 RIO Rll R12-13  -  Circuit  100K 47K 270K 680K 68K 220K 390K 82K 10K 22K -  Multivibrator  Pot.l  -  CI C2 C3 C4 VI V2-3  200K 100 p f 0 . 0 1 (if 50 p f 0 . 2 |xf  -  Circuit  6AL5 12AT7  Diagram  50 a p p r o x i m a t e l y by T = R8.C3 L n .  E  ( E  Where E ^  is  the p l a t e  Ek  is  the q u i e s c e n t  E  is  the  co  Note t h a t plate  cutoff  the q u a n t i t y  case E, , = 300 bb E^ b  =  E  = -10  co  50  Substituting  v o l t a g6 e (^bb~^D)  bb- V  + E  co  voltage of the i  s  tube  the v o l t a g e  s w i n g on t h e  volts volts volts, t h e s e and the v a l u e s  e q u a t i o n g i v e n shows t h a t This  checks  w h i c h was  3300  microseconds.  The Gate C i r c u i t  d e p i c t e d i n the K2-XB i s adjusted  used here  referred  make up t h e  signal  is  found i n  micro-  practice  comprises  two K 2 - X  K2-XA and K 2 - X B .  These  s i m p l i f i e d d i a g r a m shown b e l o w , F i g . 2 2 . a r r a n g e d as  a DC f e e d b a c k  input resistance  a p p l i e d t o R7 and i s is  t o as  t o be -1 by means  gether  voltage  a p p r o x i m a t e l y T = 3250  out w i t h the v a l u e  circuit  Philbrick amplifiers  gain is  f o r R8 and 03 i n  ( F i g . 23.)  The g a t e  this  sees.  bb-Eb»  voltage  plate  seconds.  are  ( E  of V 2 A .  In t h i s  the  supply  bb+  not allowed to  of P o t .  a m p l i f i e r whose  5.  R7 and R8 t o -  to K2-XB.  the DC v o l t a g e operate  The i n p u t +  |^^| •  K2-XB b e c a u s e  However, of  the  51  feedback V1B i s  a c t i o n of K2-XA.  conducting and a c t s  K2-XA t h u s It  is  keeps t h e  o n l y when t h e  multivibrator to  rise.  conditions,  tube  as  resistor  K2-XA.  the feedback  cutoff  that  the  i n p u t g r i d o f K2-XB i s  means t h a t  the  m u l t i v i b r a t o r pulses  two P h i l b r i c k a m p l i f i e r s  o u t p u t f r o m K2-XB i s  a t r a i n of negative  tude  of which i s  that  of  -JAxj  3300  Adjustment of P o t .  able  i n the t e s t  change  amplitude  of  the ampli-  microseconds,  -1.  5  - S i m p l i f i e d Diagram  5 changes  the  g a i n of  This adjustment  c i r c u i t i n case  the v o l t a g e  the  pulses.  The Gate C i r c u i t  normally kept at  going  operate  the  Pot.  22.  volts.  allowed  so t h a t  pulses,  and the d u r a t i o n i s  the m u l t i v i b r a t o r  which i s  zero  by the n e g a t i v e  g a t e formed by t h e s e  Fig.  to  j u n c t i o n between R7 and R8 a t tube V1B i s  pulses  This  Under no s i g n a l  it  becomes  is  K2-XB made  necessary  availto  corresponding to X without a f f e c t i n g  the p h a n t a s t r o n  pulses.  The a m p l i t u d e  of  the the*  + 300  volts  —  ;  + jAX[  w  t o Gate DC  Holding Vplta;ge - X  Fig. -300  volts  Pot.i Pot.2 Pot.3-4 Pot.5  - 20K - 30K - 10K -200K  V1A,B  -12AT7  23. The Gate C i r c u i t  Diagram (Test  Rl-2 R3 R4 R5 R6 R7-8 R9-10  -  270K 47K 2 w a t t 47K 270K 33K 47K 1 Meg.  CI C2-4 C5-6 Dl-3  -  1 rlf 0.01 | i f 7rr30 p f ( t r i m m e r ) Germanium d i o d e s t y p e - 1N-191  Circuit)  Ul  ro  53  p h a n t a s t r o n p u l s e s depends this  The d e t a i l e d  DC v o l t a g e  a cathode equal  to  +  c i r c u i t diagram i s f o l l o w e r the  JAx| .  d i o d e g a t e DGA i n the the  This  shown i n P i g . 2 3 .  output of which i s voltage  galvanometer  t e r m i n a l marked DG i n F i g . 2 3  voltage  from VIA i n  (+|Ax| ).  circuit  Tube V I A i s  on the DC v o l t a g e  is  taken to  a the  positioning circuit via  •  It  also  forms  to the P h i l b r i c k a m p l i f i e r gate under  the  input  discussion.  +JAx| c a n be v a r i e d between 0 and 20 v o l t s by a d j u s t m e n t Pot.  1,  Pot.  Pot.  1 the v o l t a g e  resistors the  size  2 is  adjusted  so  on V I A c a t h o d e  The g r i d o f  tube V1B i s  R4 and R 5 .  A negative  of t h e p u l s e  necessary  D i o d e s DI and D2 a r e any p o s i t i v e  overshoot  D i o d e D3 and c a p a c i t o r s circuit  to  that  eliminate  of  at  is  0  held  to  cut  lowest  setting  of  -45 v o l t s  by  volts. at  voltage  about is  off  used this  to  reduce  tube.  c o n n e c t e d a c r o s s R6 t o  the v o l t a g e  C5 and C6 a r e  overshoot  the  of the  of  prevent  on t h e g r i d of V 1 B . also  connected i n the  o u t p u t waveform from  K2-XB. Bias the u s u a l  for  the  Philbrick amplifiers  manner by r e s i s t o r  RIO and P o t .  4 for  K2-XB.  R 9 and P o t .  is  3 for  provided i n K2-XA and by  54  THE RESULTS OF THE GALVANOMETER RESPONSE TESTS The  r e s p o n s e of  input  signals  ratios  (i.e.  is  the  of d i f f e r e n t different  galvanometer pulse  values  l i m i t e d by c o n s i d e r a t i o n s  pulse  for values  q u i r e d were longer  of K ) .  lengths  became The  K = 4.  c r i t i c a l and was  4 different  56 t o  was  found t h a t  It  deflections  of  the r e s p o n s e  350 ^ s e c s .  I n the  over a l l  a further  250 u s e e s .  these r e s u l t s  are:  photographs  there  lengths  the  the  the  This  are  initial  pulsed  The p u l s e  a slight  i.e.  case  the  input this  difference  pulse  obtained curves  for  of  of  the  signal,  for  c a n the beam be the  point is  r e q u i r e d to  usees.  between the  outward and i n w a r d movements o f  for  time  1800 u s e e s  some time a f t e r  lengths  while  positioning  P l = 210 (isecs and P2 = 90 is  of  re-  shown on pages  compares w i t h  until  lengths  than 4,  amplitudes  In n e i t h e r  stationary  c a s e of  for K  drift.  s y s t e m was  amplitudes  to a s t e p i n p u t .  considered perfectly  to  and t h e r e s p o n s e  from 0 t o X , t h a t  c o u l d be k e p t a t  voltage  was  could supply -  subject the  It  the pulse  the a d j u s t m e n t  for  for  than 4,  reduced,  galvanometer,  movement.  can a c c e p t .  of K g r e a t e r  The d r i v i n g waveforms  59.  to h o l d i n g  For Values  b e s t performance  for  The u p p e r v a l u e  l o n g e r t h a n the a p p a r a t u s  t h a n 250 ^xsecs.  examined  of a c c u r a c y and by t h e maximum  of K l e s s  the p o s i t i o n i n g time was  in  amplitude  c u r r e n t which the galvanometer  found t h a t  was  the  initial reached  achieve In  the  pulse galvanometer.  55 However,  i t was f o u n d l a t e r  equal without a f f e c t i n g  that  these times  the response  W i t h K = 6 t h e waveforms shown on page 60,, lisecs,  The i n i t i a l  for  c o u l d n o t be m a i n t a i n e d o v e r a  Also  it  which o c c u r r e d a t sponse was of  all  no b e t t e r  the p u l s e s  than f o r  and meant t h a t  the  meter  a l l values  ment u s e d  for  the  tests  the  same c o m p a r t m e n t .  did  not s t a b i l i z e  to a constant  the  the  some  280  this  re-  time. overshoot  the  c a s e when K = 4 ,  of  total  re-  The d u r a t i o n  temperature  lamp and the  of  of  the  galvano-  With the  galvanometer  c o n d i t i o n s the  2 hours a f t e r  temperature  the  arrangewere  from t h e  in  performance  apparatus  t h e a p p a r a t u s had b e e n  l e v e l b y the h e a t  for  movement.  performance.  Under t h e s e  until  s w i t c h e d on and the raised  of K t h e  considerably affected  is  are  P l = 180 ^isecs P2 = 80 ^ i s e c s ,  b o t h i n w a r d and outward d i r e c t i o n s For  long p e r i o d of  to e l i m i n a t e a small  amplitudes  f o r K = 6 are  maximum a m p l i t u d e  was v e r y s e n s i t i v e ,  sult  made  waveforms.  p o s i t i o n i n g time h e r e  but because the adjustment  was f o u n d i m p o s s i b l e  c o u l d be  lamp.  was  56  D r i v i n g Waveforms a n d G a l v a n o m e t e r R e s p o n s e SHEET 1.  Taken f o r 16 mm.  Photographs  d e f l e c t i o n of the galvanometer  and K = 4 : l .  I n p u t v o l t a g e X = 15 v o l t s p r o d u c i n g a h o l d i n g  of 16 mAs.  P u l s e a m p l i t u d e 60 v o l t s ,  producing a pulse  S t e p I n p u t (x o n l y )  Input.  current  current  o f 64 mAs. Pulsed  Scales per square.  Driving Waveforms,  Vertical 30 v o l t s . Horizontal lOOOnsecs o  Galvanometer Response. (P-M O u t p u t )  Vertical 1 volt. Horizontal 1000 Usees.  The p h o t o g r a p h s b e l o w a r e o f t h e same P u l s e d I n p u t s i g n a l and t h e g a l v a n o m e t e r r e s p o n s e c u r v e s a s above b u t w i t h t h e t i m e s c a l e expanded  10 t i m e s - i . e . t o 1 s q u a r e = 100 u s e e s .  The 0 t o X S i g n a l  The X t o 0 S i g n a l Vertical 30 v o l t s .  Driving Waveforms  Horizontal 100 u s e e s . Vertical 1 volt.  Galvanometer Response. (P-M O u t p u t )  Horizontal 100 M-secs,  P o s i t i o n i n g Times: W i t h S t e p I n p u t  . . . . . . .  With Pulsed Input (a) f o r the 0 to X S i g n a l . (b) f o r the X to 0 S i g n a l .  1100  Usees.  350 U s e e s . 350 U s e e s .  57  Driving  Waveforms and G a l v a n o m e t e r Response SHEET 2 .  and  K=4:l.  Taken f o r  Input v o l t a g e  current  of  12 mAs.  current  o f 48 mAs.  Photographs  12 mm. d e f l e c t i o n o f  X = 11.25  volts  producing a  P u l s e a m p l i t u d e 45 v o l t s ,  Step Input  (x  only)  Pulsed  the  galvanometer holding  producing a  pulse  Scales per square.  Input.  Vertical 30 v o l t s .  Driving Waveforms  Horizontal 1000 |jsecs. Vertical 1 volt.  Galvanometer Response. (P-M O u t p u t )  The signal time  Horizontal 1000 | i s e c s . photographs  below a r e  and t h e g a l v a n o m e t e r  scale  expanded 10 t i m e s The  of  response -  i.e.  0 to X S i g n a l  the  same P u l s e d  c u r v e s as to  Input  above but w i t h  1 s q u a r e = 100  the  usees.  The X t o 0 S i g n a l Vertical 30 v o l t s .  Driving Waveforms  Horizontal 100 u s e e s . Vertical 1 volt.  Galvanometer Response. (P-M O u t p u t )  Positioning  Horizontal 100 u s e e s .  Times;  With Step Input With P u l s e d Input (a) f o r the 0 to X S i g n a l (b) f o r the X to 0 S i g n a l  1800  Usees.  360 U s e e s . 350 U s e e s .  58 D r i v i n g Waveforms and Galvanometer Response Photographs SHEET 3. and K = 4 : l .  Taken for 8 mm. d e f l e c t i o n of the galvanometer  Input voltage X = 7.5 v o l t s producing a h o l d i n g  current of 8 mAs.  Pulse amplitude 30 v o l t s ,  producing a pulse  current of 32 mAs. Step Input (X only)  Pulsed I n p u t .  Scales per square,  Driving Waveforms  Vertical 30 v o l t s . Horizontal 1000usees.  Galvanometer Response. (P-M Output)  Vertical 1 volt. Horizontal 1000 usees.  The photographs below are of the same Pulsed Input s i g n a l and the galvanometer response  curves as above but with  the time scale expanded 10 times - i . e . The 0 to X S i g n a l  to 1 square = 100  Usees.  The X to 0 S i g n a l Vertical 30 v o l t s .  Driving Waveforms  Horizontal 100 usees. Galvanometer Response (P-M Output)  m  i  Vertical 1 volt.  n  Horizontal 100 ^isecs.  mm Positioning Times;  With Step Input  • 1800 usees.  With Pulsed Input (a) for the 0 to X Signal . (b) for the X to 0 Signal .  400 usees. 300 usees.  59  D r i v i n g Waveforms and Galvanometer Response SHEET 4. and K = 4 : l .  Photographs  Taken f o r 4 mm. d e f l e c t i o n of the galvanometer  Input voltage X = 3.75 v o l t s producing a h o l d i n g  current of 4 mAs.  Pulse amplitude 15 v o l t s , producing a pulse  current of 16 mAs, Step Input (x only)  Pulsed Input.  Scales per square, Vertical 30 v o l t s .  Driving Waveforms  Horizontal lOOOusecs. Vertical 1 volt.  Galvanometer Response, (P-M Output)  Horizontal lOOOpsecs.  The photographs below are of the same Pulsed Input s i g n a l and the galvanometer response time scale expanded 10 times - i . e . The 0 to X S i g n a l  curves as above but with the to 1 square = 100 usees.  The X to 0 S i g n a l Vertical 30 v o l t s .  Driving Waveforms  Horizontal 100 u sees. Vertical 1 volt.  Galvanometer Response (P-M Output)  P o s i t i o n i n g Times;  Horizontal 100 usees. With Step Input With Pulsed Input (a) for the 0 to X S i g n a l . (b) for the X to 0 S i g n a l .  1500 u s e e s . 350 u s e e s . 300 u s e e s .  60  D r i v i n g Waveforms and G a l v a n o m e t e r SHEET 5 . and K = 6 : l . rent  of  current  Input  16 mAs. of  Taken f o r  Response  16 mm. d e f l e c t i o n  v o l t a g e X = 10 v o l t s , Pulse  Photographs  amplitude  of  the  galvanometer  producing a holding  60 v o l t s ,  producing a  cur-  pulse  96 J5AS. The Complete Signal  The 0 t o X Signal  The X t o 0 Signal  Driving Waveforms  Galvanometer Response (P-M O u t p u t )  Horizontal Scales per square: V e r t i c a l Scales per s q u a r e : -  D u r a t i o n of P u l s e s :  Positioning  Times:  1000 ^ s e c s .  for for  the the  100 u s e e s .  D r i v i n g Waveforms . . . . . . Galvanometer R e s p o n s e . . .  Both P l Pulses  160  jisecs.  B o t h P2 P u l s e s  90  usees.  100  usees.  30 v o l t s 1 volt.  With P u l s e d Output (a) (b)  for for  the 0 to X S i g n a l . . the X t o 0 S i g n a l . .  300 280  (isecs. usees.  61  CONCLUSIONS i)  An A n a l y s i s  of  the  Results  When c o n s i d e r i n g t h e figures the  show t h a t  time f o r  system,  if  the  one frame  at  the  positioning  the  function.  least time.  Prom t h e practise,  it  ing factor theory.  beam c a n be a c c u r a t e l y of  the  the g a l v a n o m e t e r  tween f r a m e s ,  were r e q u i r e d  would leave  galvanometer  is  considerably  The t h e o r e t i c a l of  frequency  f^=  325  c/s.  less  Value  oscillation  fn=  and  i6co  n  •  cation and the  is  and the  62  Prom (2)  a = 0.85co n  damp-  linear natural  resonant  equations:  -  0-85  obtained  between t h e o r y and p r a c t i s e  an e m p i r i c a l r e s u l t .  transient  the  (1)  obtained  complicated  in  ton  results  b e c a u s e of  for  (2)  ° =  possible  of  6io n  Prom ( l )  is  obtained  damped  by t h e  be-  generating  computed f r o m the  related  = j l -  present  be a l l o w e d  value  From the  This is  was  1000 c/s  a =  to  500 p,secs f o r  effective  of  within  With the  t h a n i n d i c a t e d by  They are  6 = 2fifd  positioned  response times the  the  t o be p o s i t i o n e d  500 (isecs w o u l d have This  response,  f u n c t i o n drum.  would appear t h a t  frequency  lation  galvanometer  the  in practise  good  corre-  i f a is  taken  No t h e o r e t i c a l  extreme  conditions  s p e e d of i n the  as  justifi-  response  damping  fluid  62  and the signal  suspension  of  coil.  where K = 4 and where the  applied,  t2  is  be a p p l i e d a t obtained  in  indicates  300 u s e e s ,  a signal  usees,  ii)  Recommendations If  for  a shorter  the most  satisfactory  reducing  the  connection, the  it  is  of  with  step  210  is  usees  the 4 u s e d a t  possible  - e.g,  required,  t^ =  this  the  probably  w o u l d be by  were d o n e ,  slight  however,  overshoot. movement  the d r i v i n g s i g n a l  is  show t h a t  have  the  the  operate  be n o t e d t h a t  to damp-  damping. pulses  for  same l e n g t h .  The p r o p o s e d  In  re-  due  Hence some o t h e r f o r m o f  have b e e n s i m p l i f i e d .  pulse  If  that  c a n be made t o  will  is  electrical  results  present.  Here i t  theory  In p r a c t i s e  in eliminating a l l  t h e damping f l u i d .  2 phantastrons  = 250 | i s e c s ,  accomplishing this  damping.  outward and i n w a r d movements  positive  third  theoretically  t j = 140 u s e e s .  c o m p l e t i o n of  Experimental  quirements  compares  p o s i t i o n i n g time  m i g h t be e x p e r i e n c e d  i n F i g , 24.  s t e p must  o f eC f o r a  F u t u r e Work  means  i n g m i g h t be a t t e m p t e d  of  the  This  that  galvanometer  maining a f t e r  that  time u n t i l  where K = 6 and t 2  ( f o r o ( = ^6(jo n )  movement of  value  practise.  150  trouble  Using this  the s e c o n d  t-]_ = 220 p. s e e s .  For  this  the  the  This  circuit  b l o c k diagram the  signal  o c c u r r i n g whenever a new d e f l e c t i o n  is  means instead  is  input signal  The t r i g g e r  both  is  shown renow a  required.  —X  Trigger  pulse  Pulse Adding Amp.  X + P Adder  Drive Invert AC  P2 Trigger  Galvanometer Drive Circuit  Galvanometer  Fig.24.  B l o c k Diagram f o r  the Proposed  Positioning  Circuit  Galvanometer  64 Its  d i r e c t i o n does n o t depend on the  t o t h e two g a t e s DGA and DGB a r e The |AX|  signal In  is  order  from a f f e c t i n g circuit  no l o n g e r  the a c c u r a c y  drift  of  to  correct  one t e s t  zero p o s i t i o n  the g a l v a n o m e t e r .  each r o t a t i o n  Provided that eliminated,  due t o t h e This  part  inputs  D,C,  amplifiers  this.  This  c a n be  f u n c t i o n which w i l l A bias  the accom-  check  signal  the  will  be  pro-  t h i s f u n c t i o n to e l i m i n a t e t h e z e r o e r r o r of the  galvanometer  desired.  of t h e  function generation,  of  d u c e d from  The  now + A X and - A X r e s p e c t i v e l y .  p l i s h e d by means of  of A X ,  required.  to prevent  must be a r r a n g e d  sign  the  of  the drum.  errors  electrical  signals  Thus the main s o u r c e mechanical alignment of  the  due t o d r i f t  system w i l l  of of  have  are  completely  can be made as error the  i n the frames  accurate  as  system w i l l  be  on t h e d r u m .  t o be v e r y c a r e f u l l y  en-  gineered. From the groundwork has curate  it  c a n be  been c o m p l e t e d f o r  and v e r s a t i l e  satisfies thesis,  foregoing  method of  the r e q u i r e m e n t s  the  concluded that c o n s t r u c t i o n of  function generation  l a i d out a t  the an  ac-  which  the b e g i n n i n g o f  this  65 APPENDIX The P h i l b r i c k o p e r a t i o n a l p l u g - i n unit p r i m a r i l y intended for features  balanced  mum d r i f t .  differential  F o l l o w i n g are  Model K 2 - X O p e r a t i o n a l 30,000 DC, open-loop POWER REQUIREMENTS 7 . 5 ma. a t +300 VDC 5.2 ma. a t -300 VDC 0 . 7 5 amp. a t 6 . 3 V INPUT IMPEDANCE Above 100 Megohms  OUTPUT IMPEDANCE Below 300 ohms o p e n - l o o p ; l e s s t h a n 0 . 2 ohms f u l l y f e d back ;  VOLTAGE RANGE - 5 0 t o +50 VDC f o r inputs (together) -100 to +100 VDC f o r o u t p u t (maximum)  feedback  inputs  for  general  K2-X i s  a  compact  operations.  versatility  and  It mini-  specifications;  Amplifier  GAIN  DRIFT RATE 5 m i l l i v o l t s p e r day r e f e r r e d t o the i n p u t  the  amplifier  INPUT CURRENT Less than 0.1 micro-amp. for e i t h e r input OUTPUT CURRENT - 2 m a . to +2 m a . , d r i v i n g 25K l o a d f r o m - 5 0 t o +50 VDC INPUT BIAS P o s i t i v e input should operate 0.6 V h i g h at balance (external b i a s ) RESPONSE 1 usee, r i s e time w i t h band w i d t h o v e r 250 KC when u s e d as an i n v e r t e r AUGMENTED POWER 100 K 2W r e s i s t o r c o n n e c t e d between o u t p u t and -300 VDC s u p p l y . D r i v e s 33K l o a d o v e r f u l l v o l t a g e range ±100 volts  ~0  +300  i n (2).  ( D -300  Rl  - 150 K .  R2  - 150 K , ,  R3  - 470-K*  R4  -  R5  - 180 K .  R6  -  R8  -  1 watt  B10-  R  1 Meg.  10 M e g .  -  1.5 M e g .  R12-  4 . 7 Meg.  n  ON ON  220 K . out  Symbol  68 K .  Ry — 2 . 2  -  R9  K.  82 K . Fig.  25  Cl  -  15  pf.  C2  - 5000  pf.  c  -  pf.  3  7.5  Resistor  tolerance  Model K 2 - X O p e r a t i o n a l A m p l i f i e r . George A . P h i l b r i c k R e s e a r c h e s ,  Inc.  - 5%  67  BIBLIOGRAPHY 1.  Korn,  2.  C h a n c e , H u g h e s , M a c N i c h o l , S a y r e and W i l l i a m s " W a v e f o r m s " . New Y o r k M c G r a w - H i l l , 1949 ( M . I . T . R a d i a t i o n L a b . S e r i e s , V o l . 19).  3.  Hildebrand, B.P. A S a m p l i n g Type F u n c t i o n G e n e r a t o r . M . A . S c . T h e s i s , U n i v e r s i t y of B r i t i s h C o l u m b i a , April, 1956.  4.  Fiorentino, J.S. T i m i n g and C o i n c i d e n c e C i r c u i t r y f o r a T i m e - S h a r i n g Analogue F u n c t i o n G e n e r a t o r . M . A . S c . T h e s i s , U n i v e r s i t y of B r i t i s h C o l u m b i a , A p r i l 1956.  5.  Smith,.Otto J.M. " P o s i c a s t C o n t r o l of Damped O s c i l l a t o r y Systems". P r o c e e d i n g s o f the I . R . E . , v o l , 4 5 , n o , 9 , p p . 1249 - 1255. S e p t . 1957.  6.  Edwards, C . M , " P r e c i s i o n E l e c t r o n i c S w i t c h i n g With Feedback Amplifiers". P r o c e e d i n g s of the I . R . E . , v o l . 4 4 , n o , 1 1 , p p . 1613 - 1620, N o v . 1956,  7.  Wass,  8.  M i l l m a n , J . and P u c k e t t , T , H , " A c c u r a t e L i n e a r Diode G a t e s " . P r o c e e d i n g s of the I . R . E . , p p . 27 - 3 7 , J a n . 1955.  9.  W i l l i a m s and M^oody. " R a n g i n g C i r c u i t s , L i n e a r Time Base G e n e r a t o r s and A s s o c i a t e d C i r c u i t s " , I n s t i t u t e of E l e c t r i c a l Engineers J o u r n a l , v o l , I I I A , Radio L o c a t i o n , 1946, p p . 1188 - 1198.  10,  G . A . and K o r n , T . M . E l e c t r o n i c New Y o r k , M c G r a w - H i l l , 1952.  Analogue  Computers  C.A.A, I n t r o d u c t i o n to E l e c t r o n i c Analogue New Y o r k and L o n d o n , M c G r a w - H i l l , 1955,  J e n k i n s , F . A . and W h i t e , H . E , F u n d a m e n t a l s York, McGraw-Hill, 1950.  of  Computers.  Bidirectional v o l , 43,  Optics.  New  

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