Tektronix FG 504

14 .
A d j
u st
Output Am p lifier R es p o n se (C922, C1090,
R 950, R 1050)
Connect t h e F G 504 O U T P U T t h roug h α 50
Ω coaxial
cable to α 50 Ω termi n ation at t he
vertical in p ut of t h e
oscillosco p e .
Set t he F G 504 MU L TI PL
I
ER to
10 5 . Adj u st t h e os-
cillosco p e vertical se
n sitivity a n d s w ee p s p ee d to display
one
or
more complete c y cles of t h e sq u are w
ave at about
6-divisions a mp litu de . Ad j u st triggeri
n g
to view
the
lea d ing e d ge of t h e p ositi v e-goi n g slo p
e . Adj u st C922 (S q
Co mp L ongTerm)on
t he Α 1 MAIN board for opti m u m
s q uarecorner
i n t he first 100 ns fro m t he risi n g an d
falling
e d ges
. Ad j ust C1090 (S q Co m p Short Term) on
t h
e
Α 1
MAIN boar d for optimum s q uarecorner
wit h aberrations
less t ha n 5 ο / ο over t he first 20 ns
fro m t h e rising a nd falling
edges . Ad j
ust R 950 (S q Com p L eading Ed ge) on t he Α 1
MAIN boar d for m inimum rise time, o p
tim u m s qu are
corner, and m inimum aberrations
overt h efirst 20 nsfrom
t h e leading e d ge . Ad j ust
R
1050 (Sq Com
p Trailing E dge)
on t h e Α 1 MAIN boar
d for m inimum fall time, o p ti m um
s qu are corner,
a nd mini m u m aberrations over t h e first
20
ns f rom t h e traili n g edge . C h ec k th at rise timean
d fall
time of t h e square wave is eq ual to or
less t h an 6 ns .
R e p eat step14 as
n
ecessary to ac
hieve minimum aber-
rations (eq ual or
less t h an 5 ο/ο +30 m V ) and rise time of
e q
ual
or
less t h an 6 ns .
15 . Ad j u st A m plit ud e F lat n ess (8365, C325,
C340)
Set F G
504 controls as follows :
S W E EP D UR ATIO N 1 ms
VA
R

F ully cc w
Tria n gle pus h button

In
F RE Q UE N C YH z (STA
R T) 1
STO P F RE Q

40
MUL TI PL I ER 10'
FR EQ UEN CY VE RN I ER F u lly c w
R IS Eand F A LL TIME

F
IX
E
D
<_6
ns
VAR

F ully ccw
ATT E NU ATO R ( d B)

0 d B
VAR

cw
TR IGG ER
F REE R UN

Ι
η
All ot her butto
n
s

Out
Con n ect α 50 Ω coa x ial cablefrom
t
he F G 504 L I NE A
R
S W E EP O UT PU T to
t h
e oscilloscope
e x ternal trigger
input . Set t he time base swee p speed to0 .2 m s p erdivision
and trigger externally on t h e n egati v e slo p
e
of
t he
wavefor m . A d j ust t
h
e oscilloscope
vertical sensitivityfora
6-divisio
n
d is p
lay .
Set
t he F G 504 MUL TI PL IE R to 10 ή .
Ad j ust
t h
e
S WE E P D U RATIO N V A R IA BLE so only one
envelo p e is visible across t he e n tire horizo n tal graticule .
V erticall y center t
h
e
left
si
d e
of
t h is e n velope . A d j ust R 365
( H F L
oo p
DC Le v el) on t h e Α 3 L OO P boar d so t h at t h e
Calibratio n P roce d ure-
F G504 (S N Β 040000 &
UP)
Ad j ust m
ent P roced u re
rig
h t
si de of
t he envelo pe is also vertically centeredon
t he
gratic u le . Ad j u st C325 an d C340
(HF L oo p Com p ) on t he
Α 3 L OO P boar
d
so
t h at t h e rest of t h e wavefor m is
a pp ro
x imately symmetrical aro u n d t he center h orizontal
graticule
line wit h m ini m um amplitu d e in t he center . (See
F
igure 4-1 .) Consi d erable i n teraction exists between
C325
and C340 . R ea d j ust as necessary to
obtain t h e best
s ym metry an d am p lit ud e flatness . C
h ec k t h at t he pea k -to-
pea k am plit ud e of t
h e envelo
p
e is between 4 .5 d ivisions
a n d 7 .5 d ivisions
at
all
p oints on t h e waveform . Set t he
F G
504 S W E EP D U R ATIO N to off .
F ig . 4-1 . Am p litude flatness c hec k .
16 . A d j u st Si n e
F latness (C857)
Pus h t he sine- w ave p u s h button i n . Set
t h
e
FRE-
Q UEN CY
H
z (STA
R T) d ial
to
40 . Ad j ust C857 (Sine
Flatness) on
t h
e
Α 2 FUN CTIO N boar d for α 5 .5 division
sine-wave am p litude . Disconnect t he 50 Ω cables and
termination .
17 . Ad j u st Top Dial Calibration ( R 145)
Set t he F G 504
M
U
LTI PL I ER
to
10' . Set t h e F R E -
QU E
N
CY
Hz (STA R T) dial to exactly 40 . Connect T R IG
O U
T P
U
T t h roug h α coaxial cable an d 50 Ω termination to
α freq u e n cy counter . A d j ust R 145 ( Χ 40 Cal) on t h e Α 3
L OO P board for α rea d ing of 40 kH z wit h i n ±3 ο / ο
(±1
.2 kHz) . C hange t
h
e
M
UL
TI PL I E R setti n g to 10" and
c
h
ec
k for α reading of 400 k H z w it h in ±3 ο/ο (±12 k Hz) .
18 . Ad j u st
106
R a n ge Ti m i n g (C195)
C h ange t h e MU L TI PL I ER to 10` . A d j ust C195 (40 MH z
Cal) on t h e Α 3 L OO P boar d for α readout of _>40 MHzin all
t h ree functio
n s-square, triangle,
and sine
wave .
4-
1 1