Tektronix FG 504

Cali b ration P roce d ure- F G 504 (S N
Β
040000
& UP)
A dj ustme n t P roced u re
19 . Ad j
ust
10 5
R
ange
Timi
ng (C242)
C han ge t h e F
G
504 MUL TI PL I ER setting
to 10 5 . Ad j ust
C242 (4 MH z Cal) on t he Α 3 L OO P board for a readout of
4 MH z wit h in 3% ο (±120 kHz) .
20 . A dj ust 20 MHz Timing ( R 128)
Set t h e FRE Q UEN CY Hz (STA R T) dial to exactly 20 .
Set t h e MUL TI PL I ER to 10 6 . A dj ust R 128 (20 MH z Cal) on
t he
Α
3
L
OO
P
board for α fre que
n
cy of 20 MHz
wit h
i
n
specificatio n limits (17 .6
MHz to
22 .4
MHz)
for
all
t hree
fu n ctio n s-s q uare, triangle, a nd si n ewave) . NOTE :
20 MHz Cal will i n teract wit h 40 MHz Cal .
21 . C
h
ec
k
a
n
d Ad j
ust H ig hF requency Dial Trac k i ng
( R 128, C195, C325, C340)
C
h
ec
k t h at t h
e o
u t p ut
frequency from
4 MH zto40 MH z
is wit h i n s p ecification limits for all t hr ee f un ctio n
waveforms . If dial trac k ing is not wit h i n specificatio n
limits, it may be necessary to slig h tly rea d j ust R 128
(20 MHz Cal), C195(40 MH z
Cal),
and C325 and C340 (
ΗF
L
oo p
Com p ) to ach ieve p roper dial acc u racy . O p timum
trac k ing will result if C325 and C340 (HF L oop Com p )
a dju stme n ts are p erforme d so as to mai n tain symmetrical
amplit ud
e
flatness aro un d t h e graticule vertical center
li ne . Rep eat ste p 15 a nd c h eck t h at am p litude flat ness is
wit h in specification limits . If n ecessary, repeat steps 15
t h roug h 21
.
22 . Ad j ust Sto
p
Fr eq ue n cy Dial R ange ( R 10)
W it h t he F
G
504 MUL TI PL I ER at 10 6 , pus h t he STO P
FREQ/S WEEP butto n i n to STO P FRE Q mo de . Set
S WEEP D UR ATIO N to 10 s and FRE Q UEN CY Hz
(STA R T) d ial to 1 . R otate t he STO P FRE Q dial so t h at t he
in dex mar k p oi n ts to 40on t h e FRE Q UEN CY Hz (STA
R
T)
dial . C han ge t h e MUL
TI PL I
ER
setting
to
10' and a dju st
R 10 (Stop F re q Cal) on t h e Α 3
L
OO
P
board
for
afre q ue
n
cy
of 40 kH
z .
Disconnect
termi n atio n and cable from fre-
q uency cou n ter a nd F G 504 .
23 . Ad j ust L i n ear an d L ogarit h mic Swee p
Am p litu d e
( R
1460,
R 1475)
Set t h e oscilloscope
time b ase
for
2 ms/ d ivisio n ,
trigger source to i n ternal, and t he vertical for do coupled
.2 V /divisio n sensitivity . Connect α 10 Χ p robe to t
h
e
oscilloscope ve r tical i np ut, t he p robe grou
n
d cli p to
t h
e
F G 504 ch assis, a nd connect t he probe ti p to Ρ 1500 p i n 1
R am p on t he Α 2 FUN CTIO N board . C h ange t h e F G 504
S WEEP D UR ATIO N setti
ng
to 10 ms .
R
ecord
t h
e
voltage
level
displayed on
t he oscilloscope . R elease t h e F G 504
STO P FREQ/S
WEEP
button outto
t he S WEEPmo d e, and
ad j ust
R
1460 (
R amp Peak ) on t he Α 2 FUN CTIO N board
for α d isplay voltage level at t he peak of t h e ramp equal to
t h e p reviously recor d ed voltage . P ush t he F G 504 L OG
4- 1 2
S
WP
/
L I N
button
i n
to t
h
e
L
OG S
WP
mode, and ad ju
st
R 1475 ( L
og
P eak )
οη
t h eΑ 2 FUN CTIO N
boar
d
so
t he p eak
of t h e logarit h mic ram p is at t he sameam p litude as t he
o r igi n ally recor d ed voltage . Set S WEEP D UR ATIO N to
O FF .
24 . A d j ust R ise an dF all Time Symmetry ( R 610)
Co nn ect t h e F G 504 O U T PU T t h roug h α 50 Ω cable
an d α 50 Ω termi n atio n to t h e oscillosco pe vertical input .
Push t hesq ua r e wave pus h butto n in . Set t h e Μ UL TI PL I ER
to
10 ° , FRE
Q
UEN CY
Hz
(STA R T) dial to 10, R IS EAN D
F A LL TIME to .1 μ s, and V A R R IS E A N D F A LL TIME
co n trol fully cw . Obtain α waveform d is p lay of o ne
com
p
lete cycle ce
n
tered vertically and
h orizontally
on
t he
graticule
.
Ad j ust
R
610(
R
iseand
F all
Sym)ontheAl MAIN
board so t h at t h e top an d bottom of t he waveform are
e q ual i n duratio n .
25 . Ad j ust AM B ala n ce ( R 870)
Co nn ect α 1 kH z tria n gle waveform of +2 .5 V and
-2 .5 V (5 V ρ - p) am p litude ( p roduced
from
α ge
n
erato
r
exter n al to t he F G 504) t h roug h α 50 Ω cab le to t h e AM
I NPU T connector on t h e F G 504 . Co nn ect α 50 Ω cable
from t he trigger outp ut co nn ector on t h e tria n gle
ge n erator to t he exter n al trigger i npu t on t he oscillosco pe
a
n
d set
t h
e oscillosco p
e
for
exter n al t r iggeri ng . P ush t he
F G 504 si n e wave pus hb utton in . Set t h e FRE Q UEN CY Hz
(STA R T) dial to 30 . Ad j ust t he oscillosco p e time b ase to
dis p lay several cycles of t he mo du latio n en velo pe . Ad j ust
t h e external tria n gle gen erator d o offset and am p lit ud e
controls fo r α d is p lay wit h 100 ο/ο mo du latio n level,
1 ms/divisio n mo d ulation rate, a
n
d about 10 to 16 V ρ - ρ
am p litude wit
h
no
cli p ping
of
p
ea
k
s .
V ertically
ce
n ter t h
e
waveform envelope valleys to graticule ce n ter . Ad j ust
R 870 (AM ΒαΙ ) on t h e Α 2 FUN CTIO N board sot h e positive
an d negative pea k s of t he envelo pe a r e e qu ally sp ace d
from t he valleys of t h ewaveform envelope . Disco nn ect t h e
50
Ω
cables
from t h e tria ngle gen erator to t h e F G 504 and
test oscilloscope external trigger input co nn ector . Set t h e
oscillosco pe for i n ter n al trigge r i n g .
26 . Ad j ust Si ne Offset ( R 790)
Set t he F G 504 MUL TI PL I ER to 10', an d FRE Q UEN CY
Hz (STA R T) d ial to 10 . Pu sh t he triangle p us h butto n i n .
A dj ust t h
e oscilloscope vertical sensitivity for ap-
proximately 8 d ivisions of display, a nd adju
st
t h
e
time
base swee p s p ee d for about 5 cycles of triangle waveform .
Set t he oscilloscope vertical in p ut cou p li n gto grou nd an d
cen ter t he trace vertically . R eturn t he i n put co up li n g to t he
do p ositio n . P ush t he sine wave pus h butto n in . Ad j ust
R
790 (Sine Offset) on t he Α 2 FUN CTIO N board soth esine
wave
pea
k
s are symmetrical a b oveand below t he 0 V
(cen ter) oscillosco pe graticule li n e .