Tektronix PG 508 User Manual

R iseti ι m e M easurements
in L inear Systems
Co n sider t he r ise a nd falltime of
associate d e q ui p me n t
w h en meas u ri ng t he rise or fallti m e of α
li neardevice . If t h e
risetime of t he d evice u nd
er test is at least ten times slower
t han t
he combi n e d risetimes of t h eP G 508, t he monitoring
oscillosco p
e, an d associate d cables, t he error introd uce
d
will n ot exceed 1 ο/ο , a nd u sually may be ig nore d .
If t h e rise
or falltime of t h e test d evice is less t han te n ti
m
es
slower
t han t h e com b i n e d risetimes of
t h e testing systems,
dete r mi ne t h
e
act
u al risetime of t he device un d er test by
usi n g t he followi n g formula :
R,
_=

U R Z

, J-

R z z -d
.
. R2
. . . . . . .
R, eq uals t h e overall rise or falltime of t h e entire measu r e-
m e n t system a nd R i , R
2,
R,, etc ., are t h e risetimes or
falltimes of t he i nd ivi d ual com p o nen ts com p risi ng t he
system
.
Extern al V oltage Co n trol
Th e
h ig h
an d low
level
output voltages
can
be con-
trolle d externally t h
roug
h p i n
s
22 Β an d Α at t he rear
interface conn ector
.
F ig . 1-4 sh ows t h eeq uivale n t circ u it .
Con n ectio ns must be made fro m p ad Κ to pad L and
p ad Μ to pad Ν located as s h ow
n
on t
h
e a dj
ustment
locatio n illust r ation in t h e fol d out pages at t he rear of t h is
ma n ual . Use or d inary h oo ku p wire of t he p ro p er le n gt h .
Solder t h e wire to t h e pa d s . Also n ote t he locatio n of t he
E xt H i and E xt L o potentiomete r s on t h e outp ut boar d .
To
u se t h is feat u re, set t he f r o n t p an el co
n trols as
follows : d epress t he PRESET butto
n (PRE S ET), p lace t h e
PER IOD switc h in t he
ΕΧΤ ΤR Ι
G
O R MAN p osition, t h e
D UR
ATIO N
in
ΕΧΤ D UR an d t h e N O RMCO MPL E M EN T
switch
i
n t
h
e
N O RM position (out) . U se α screw d river to
ce
n ter t h eE xt H i and t h e p reset H IG H LEVEL co n trols .
Supp ly α voltage to t h e external h ig h inp u t (p i n 22 Β on
t h e
rear interface co nn ecto r ) equ al to t he
lowest external
i nput voltage d esired
(maximum 20 V) .
~ 12 Κ j
Ι
E xt H i 1 22Β Ι R 1234 Ι
Ι E xt Lo
Ι
22 Α

Ι
R 1230

Ι
REV . Β , A PR . 197 7
Ι R 1236
Ι
Ι R 1232 ~
Use r
i n stalle d
ju m pe r s
- Ι
-5 .2 V
F ig . 1-4 . Eq uivale n t ci r cu it of exte rn al
i npu t
fo
r
ou
t p ut voltage control .
O pe r
ati
ng
I n structio n s- P G 508
Now a dj ust t h e fro n t p a n el preset HIG H
LE V EL control
for an OU T PU T voltage eq ual to
t he minim u m d esire d
ou t pu t voltage . It may be necessary to a
dju st t he preset
L O W LE V EL co n trol as t he OU
TP U T voltage is limite d to
20
V
pea
k
to
pea k o pe n circuit . T he h ig h level O UT PU T
voltage is clam p e d by t h e low level O UT PU T voltage
if t h is
r an ge is excee de d . Now apply α voltage eq ual to
t he
h ig h est exter n al co n trol voltage desired to t he
same rear
i n terface co nnector (pin 22 Β ) . Ad j
ust t he Ext H i p ote n -
tiometer
u ntil t he h ig h est d esired o u tp u t voltage is
obtai n ed . It may be necessary to a d j ust t he preset
L
O
W
L E VEL control to obtain t h ed esire d out p u t . T h e
h
ig
h level
OUTP U T voltage cann ot go below t he low level OUTP U
T
voltage d ue to t h e level control voltage clam
p
s .
T he E xt H i
an d t h e p reset HIG H LE V E
L
controls
interact . It may be
n ecessary to re p eat the above
p rocedu re several times
until t he d esired
results are obtai n e d .
Now push t
h
e
N O RM CO MP LE ME N
T
switc h
(CO MPL E
ME N T) . Center t he Ext L o an d p reset L O
W
LEVE L potentiometers . S upp ly α voltage to p in 22 Α of t he
rear
interface co nn ector equal to t he lowest exte rn al
control voltage desire d . A dj ust t he p reset
L
O
W LEV E L
control for an O U TP U T voltage
e q ual to t h e lowest
OU TP U T voltage desi
r
e
d . C h ange t h is voltage to t he
h ig h est d esired exter n al co n trol voltage . Ad j ust t he
Ext L
o
potentiometer for t he h ig h est O U T PU T voltage desire
d .
As t h ese a dj ustments i n teract, read j ust
t he preset L O W
LEVEL and t he E xt Lo
potentiometers for t he desire d
results . Do
n
ot
rea dj ust t he p reset HIG H LEV EL or t he E xt
H i potentiometers . - T h e O U TP U T voltages now vary
linearly and in d epe nd ently wit h t he exter
n
al co n trol
voltage .
Cou n te d B u r st Using t he DD 501 Digital Delay U nit
Th is ap p licatio n pe r mits p reselecti ng t h e nu mber of
output p ulses from t he P G 508 . T he even t is i n itiate dby an
externally a pp lie d sig n al o r p ulse, 5
n
s or lo
n ger . T h e time
duration
of
t h
is
sig n al or pulse h as no effect on t he output
fro m t he P G 508 .
U 780B H ig h L evel
U 780A
L
ow
L evel
Pr eset H IG H LEV EL 8775
or L O W LE VEL R785

Tektronix PG 508 Specifications

General

Brand	Tektronix
Model	PG 508
Category	Pulse Generator
Language	English