2) adjust Output Gain, R1040 (Fig. 3-47), so the right
edge of the cursor is at the right edge of the crt;
3) alternately switch the VIEW A (Digital Storage) on and
off while adjusting Input Gain, R1045 (Fig. 3-47), so the
storage signal at the right edge tracks with the non-store
signal.
Calibration—492/492P Service Vol. 1 (SN B030000 & up)
Adjustment Procedure
d. On the Vertical Digital Storage board:
1) output Gain R1024 and Output Offset R1036 (Fig.
3-47) are adjusted at the factory in the 492P only (the
alternate procedure follows). These adjustments should
not be changed; however, if they are disturbed, center
these adjustments and center Input Gain R1034 before
proceeding;
2) switch to 2 dB/DIV display mode;
3 ) using a signal near the bottom of the display, adjust
Vertical Offset R1030 (Fig. 3-47), so the stored display is
the same amplitude as the non-store signal;
4) change the REF LEVEL to raise the amplitude of the
signal to full screen;
5) adjust Input Gain R1034 (Fig. 3-47), so the stored dis
play of the high amplitude signal is the same as the non
store display;
6 ) repeat the low level and high level adjustments to
compensate for interaction.
b. Connect CAL OUT to the RF INPUT.
c. Connect the 492P and 4050-Series Controller with a
GPIB cable (both should already be turned on). Set the
492P GPIB ADDRESS switches on the rear panel for ad
dress
1 (switch 1 up, all others down).
d. Enter and run the following program:
100 DIM C(1000)
110 K = 125
120 11=0
130 FOR 1 = 1 TO 10
140 FOR J = 1 TO 100
150 C(II+J) = K
160 NEXT J
170 K=K—25
180 1 1 =11 + 1 0 0
190 IF K> =25 THEN 210
200 K=225
210 NEXT I
220 PRINT @1:”SIGSWP”
230 WBYTE @33:64,C,-255
e. Adjust the POSITION controls to center the FRE
QUENCY dot and place the baseline on the bottom graticule
line.
ALTERNATE PROCEDURE
FOR 492P INSTRUMENTS
a. Set the front-panel controls as follows:
FREQUENCY
FREQ SPAN/DIV
REF LEVEL
AUTO RSOLUTION
100 MHz
10 MHz
-10 dBm
Off
RESOLUTION BANDWIDTH 1 MHz
Vertical Display
Video Filter
TIME/DIV
Digital Storage (Option 02)
PEAK/AVERAGE
2 dB/DIV
NARROW
AUTO
VIEW A and VIEW B
Fully ccw
f. Adjust the following (Fig. 3-47A) for SN B043115 and
above to match the step waveform to the graticule:
Assembly
Horizontal Digital Storage
Horizontal Digital Storage
Vertical Digital Storage
Vertical Digital Storage
Adjustment
Output Offset, R1039
Output Gain, R1041
Output Offset, R1036
Output Gain, R1024
3-70
REV SEP 1983
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