Tektronix 5440 Instruction Manual page 70

A dj ustment-5440
3. Adjust Vertical Compensation
j.
R epeat parts c through h. If
n
ecessary, compro mise
α.
I
nstall the Calibratio n Fixture in th e left vertical
the vertical compensation adjustme nt to obtain the best
comp artmen t.
respo nse for b
ot h left and right vertical compartments .
b . Set the Test switc h of t h e Calibratio n Fixture to
V
ert
or
H
oriz +Step
R
es p and
d
epress t he 100 kH z
R
ep
R
ate
switc h. Ad just Amplitude and Position controls for α 6-
division d
is p lay ce ntere d vertically on the graticule.
c. Set the time-base unit for α cali b rated swee p rate of
2 μs/divisio n and triggeri n g for auto mode, ac co upled
from the internal so u rce . Adjust trigger level controls fora
stable
d
isplay, triggered on the risi ng p
ortion of the p
ulse .
Ce nter th e pulse
h
orizo ntally on the graticule.
d.
CHE CK-For optimum sq uare lead i ng co rner and
flat to p on the
d
is playe d pu lse with aberrations not to
exceed +0 .36 or -0 .36
d
ivisio n, with total peak-to-peak
aberratio ns n
ot to exceed 0.36 division.
e. AD JU ST-Vertical com pensation R121 for o ptimu m
flat to p on the displayed pulse, then adj ust
R
120 an d R 123,
increasi ng the sweep rate of the time-base unit to 1 μs/div
and 0.5 μs/div,
r
espectively .
R epeat as
n
ecessary to obtain
o
ptimu m flat top on the waveform . See
F
ig . 5-4 for
ad justment locations.
f. De pr ess the 1 MHz
R
ep
R ate switch on the Cali b ra-
tion Fixtu re, and set the swee p rate of the time-b ase u n it to
0.1 μs/ div . Ad j ust trigge r level co ntrols for α sta ble d
is play.
g. AD JU ST-Vertical compensations C637 (t h is ad ju st-
me nt is located on the main interface board betwee n
vertical com partments, SN Β 063251-υρ ), C115,
R
115,
C155,
R
155,
R
167, and C181 in
t
he order give n, for
opti m um squa re leading corner with a berrations within
the limits given i n part
d.
There is
d
irect i nteractio n
between C115 and
R
115, an d betwee n C155 and R 155.
B
est results are
u
sually obtained by setting
R
115 fully
cloc kwise, then adjusti ng C115 . See Fig . 5-4 for ad just-
me nt location .
5-6
ΝΟΤΕ
The Calibration F ixtu re
h
as α
h
igh ba nd wi dth, and
aberrations can typically
measure near the
specification limit. The f οΙΙοωίηg compe n sation ad-
ju stments may not be necessa ry if aber r atio n s and
bandwidth meet specification.
4. Chec k V ertical
P
osition
E
ffect
α. Set the Calibratio n Fixture and ge nerator co ntrols to
obtai n α ce n tered, positive-going, 6-division
d
isplay . Set
the time-base un it fo r α triggere d dis play on the
r
isi ng
p
ortion of th e p ulse, at α sweep rate of 20
n
s/div .
b. P ositio n t
h e 6- divisio n
d
is play down so α 3-division
display remains wit hin t
he graticule area .
c. CHE CK-F or optimum squ a re leadi ng corn er and
flat to p on the d
isplayed pu lse wit h aberrations n
ot to
exceed 0.36 division (6 .Οο/ο ) .
d. Set the Calib ratio n Fixture an d ge nerator co ntrols to
obtain α ce ntere d ,
n
egative-goi ng, 6-division display. Set
t h e time-base u nit for α triggere d d is p lay on the falli ng
portio n of th e pu lse, at α sweep rate of 20 n
s/ d iv .
e. P osition the 6-divisio n disp lay up so α 3-division
d
isplay remain s with i n t he gratic ule area .
f. CHE CK-F or o ptimum square leadi ng cor n er and
flat to p on the displaye d pulse with aberrations not to
exceed 0.36
d
ivision (6 .Οο/ο) .
5. Chec k B a n dwidt h
α. Set the Test switc h to
V
ert or
H
oriz Freq
R
esp an d
turn
t
h e Amplitude control fully cloc k wise .
b . Set the time-base u nit for α sweep rate of 1
millisecond/division .
c. Connect the si ne-wave ge n erator output to the CW
In co nnector of the Calibration Fixtu re.
d . Set the si n e-wave ge nerator for α refere nce fre-
qu ency of 3 MHz an d adj ust the output for an 8- d ivisio n
display.
h .
AD JU ST-R155 and
R
167 fo r mi nimum ringing of
e. Set the Calibratio n Fixture Positio n and Amplitude
fro nt co rn er. Adjust C637 (on the main
i
nterface board
co ntrols to obtai n α ce ntered, 6-divisio n d is play .
b
etween vertical compartments, SN Β063251-υρ ), C155
and C115 for α level front corner. After front cor n er
NOTE
ad justments
h
ave
b
een ma de, ad ju st C181 for optimu m
r
isetime and mi n im u m fro nt corner spi k e.
T
he Calibration
F
ixture C W Leveled lίghtmustbeon
a n d th e sine-wave ge nerator must be properly
i . Press the POWER switch to turn off the Oscilloscope, connected for α valid chec k.
R
efer to
t
he Calibration
a nd
i
nstall th e Calib r ation
F
ixture in
t
he ce nter compart- Fixture and sine-wave generato r ma nual for detailed
me nt. Pull POWER switch ON . inst ructions.
REV. Α,
J
AN. 1977