Tektronix 1L30 Instruction Manual page 71

;j
i C alibration— Type 1L30
3
I
• 1
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Fig. 6-14. Location of kHz/CM dispersion adjustments.
( 1 ) A p p ly a calib rated
'I
the RF input o f the
! ?
:
Fixture 0 6 7 -0 5 1 8 -0 0 ) from the Signal G enerator.
) ( 2 ) A pply a 5 0 0 kHz signal to the Mod
| 1 input connector o f the Harmonic M o du lato r from
| an accurate Audio Signal G en erato r.
| ( 3 ) Connect the M od Harm O ut connector through
| a 1 0 X attenu ato r to the RF INPUT connector of
| the Type 1L30.
| This w ill provide an IF feedthrough signal o f 2 0 0
M H z m odulated by the Audio Signal G enerator
frequency.
's i
■ y
| 7. Check Dispersion Accuracy of k H z/C M
j Ranges
I ■ .
I a. Test equipment setup is given in step 6.
b. Set the DISPERSION selector to 500.
! !
ns and Marker Selector buttons on the Time-Mark
1 /
as
Generator.
c. Check the frequency range of the IF CENTER FREQ
control. Frequency range must equal or exceed + and —
2.5 MHz from its centered (000) position.
f. Set the DISPERSION selector to the 500 kHz position
d. Center the coarse IF CENTER FREQ control.
^ and center the IF CENTER FREQ controls.
\
DISPERSION selector to 50kH z/cm .
g. Check dispersion accuracy through + and — 2.5 MHz
1 e. Check the frequency range of the IF CENTER FREQ-
I change in the IF center frequency, at each DISPERSION
| FINE control. Frequency range must equal or exceed +
selector position listed in Table 6-2.
\ and — 50 kHz from its centered position.
■ )
I .6 -1 4
I
lli « w..urj > w^* - t
100 M H z RF signal to
Harmonic M o du lato r (Test
Freq
.
Depress the 10
Set the
(A) 1 m arker/2 centimeter (Checking 500 kHz/CM disper­
sion.) Center marker is 200 MHz feedthrough.
(B) 1 marker/centimeter. (Checking
sion.)
Fig. 6-15. Typical displays when checking or adjusting kHz/CM
dispersion.
Dispersion accuracy must remain within ± 3 % .
meters) for all DISPERSION selector positions.
As the dispersion is decreased the sweep time should be
increased (slower sweep rate) to maintain optimum resolu­
tion. Uncouple the RESOLUTION control and adjust for
optimum time marker definition.
improve the marker definition at the narrow dispersion set­
tings.
TABLE 6 -2
Tim e-M ark
DISPERSION G en erato r
M arke r Selector
kH z/cm
10 ns and 1 /is
500
10 ns and 5
200
10 ns and 10
100
10 ns and 10 /.is
50
10 ns and 50 /is
20
10 ns and .1 ms
10
10 ns and .1 ms
5
2 10 ns and .5 ms
100 kHz/CM disper­
(2.4 milli­
The VIDEO FILTER may
D isplay in
centimeters
per marker
2
1
/
as
1
/ I
as
2
1
1
2
(Turn VIDEO
FILTER on)
1
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