Tektronix 1L20, Инструкция по эксплуатации

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Calibration— Type 1L20
* *
c. Depress the MARKER SELECTOR switches for lOdlS
(100 MHz) and .1 juS (10 MHz). /
d. Adjust the Spectrum Analyzer G A IN control for a dis­
play about 5 centimeters in amplitude.
e. Adjust C358 (see Fig. 6-4) for 1 marker/centimeter
over the middle eight centimeters o f the display. If the dis­
persion seems non-linear, readjust R290 (IF CF Range) while
adjusting C358 to obtain the best dispersion and linearity.
M onitor Pin P with a test oscilloscope to keep the voltage
a t this pin between —0.8 and — 1.2 volts.
f. Change the DISPERSION to 500 kHz/CM. A pply a 1
MHz signal from the Time-Mark Generator.
g. Adjust R368 (see Fig. 6-4) for 1 marker/2 centimeters.
h. If the display is not centered, adjust C384 and C385
(see Fig. 6-4) so that it is centered. If necessary, readjust
R368 for the correct dispersion again.
i. Check the kHz/CM DISPERSION linearity a t the ends
o f the IF CENTER FREQ range. W ith a marker a t the first
graticule line, the fifth marker should be within 3 millimeters
of the ninth graticule line.
j. If the 500 kHz/CM is not w ithin these specifications,
turn C384 and C385 very slightly in opposite directions
so as to keep the display centered, readjust R368 for 1
marker/2 centimeters, and recheck the dispersion at the
ends o f the IF CENTER FREQ range. Repeat this procedure
until the dispersion accuracy is w ithin specifications a t both
ends of the IF CENTER FREQ range.
k. Center the IF CENTER FREQ control and check the
dispersion accuracy at each DISPERSION/CM setting, using
Table 6-1. Position a modulation mark at the first graticule
line and check the displacement of the ninth marker from
the ninth graticule line for displays having 1 division/
First Ninth
First Ninth
Fig. 6 -5 . Typical Dispersion accuracy displays (Step 2 ) .
marker. If the display should have 2 divisions/marker, then
check the displacement of the fifth marker from the ninth
line. (See Fig. 6-5.)
TABLE 6-1
DISPERSION/CM
M o d u la tio n CRT D isplay in
S ignal | D ivisio n s/M a rke r
M axim um
Error
Notes
10 MHz .1
ij
S (10 MHz) 1
± 3%
Check W ith IF CENTER FREQ control
centered
5 MHz .1 fiS (10 MHz) 2
± 3%
2 MHz .5 [iS (2 MHz) 1
± 5%
Over range o f IF CENTER FREQ con-
trol
( ± 25 MHz)
1 MHz 1 fiS (1 MHz) 1
± 7%
.5 MHz 1 fiS (1 MHz) 2
± 1 0 %
.2 MHz 5 /tS (200 kHz) 1
± 1 5 %
500 kHz 1 n S (1 MHz) 2
_
O
O
'"
CO
+1
200 kHz
5 nS (200 kHz) 1
100 kHz 10
jll
S (100 kHz)
1
50 kHz
10 uS (100 kHz) 2
20 kHz 50 nS (20 kHz)
1
10 kHz .1 mS (10 kHz)
1
5 kHz .1 mS (10 kHz)
2
2 kHz .5 mS (2 kHz)
1
1 kHz 1 mS (1 kHz) 1
®
6 -7