TB 9-6625-2134-24
(11) Add 10 dB with variable attenuator and press MIN NOISE pushbutton off.
(12) Repeat technique of (8) through (10) above for REFERENCE LEVEL of -30,
-40, -50, -60, and -70 dBm. Total cumulative error must not exceed 1.5 minor divisions.
(Add additional .5 dB when stepping from 9 to 10.)
(13) Press NARROW VIDEO FILTER pushbutton on and repeat technique of (8)
through (10) above for -79 dBm.
b. Adjustments. If an out-of-tolerance condition is noted, perform adjustments listed
in paragraph 8 b above.
12. Display Accuracy and Range
a. Performance Check
(1) Adjust signal generator for 100 MHz at +10 dB and set variable attenuator to 0 dB.
(2) Position controls as listed in (a) through (g) below:
(a) VERTICAL DISPLAY 10 dB/DIV pushbutton on.
(b) REFERENCE LEVEL control to +10 dBm.
(c) MIN RF ATTEN control to 0 dB.
(d) VIDEO FILTER NARROW pushbutton on.
(e) VERTICAL DISPLAY 10 dB/DIV pushbutton on.
(f) FREQUENCY SPAN/DIV control to 10 MHz.
(g) RESOLUTION BANDWIDTH control to 1 MHz.
(3) Adjust FREQUENCY control to 100 MHz and center signal on crt while
10 kHz.
(4) Carefully adjust signal generator output until trace level is on top graticule line of crt.
(5) Adjust variable attenuator in 10 dB steps for a total of 60 dB.
Trace will
decrease in 10 dB 1.0 dB steps on crt. Record error for each 10 dB step.
(6) Record crt position (reference) and decrease signal generator output by 30 dBm.
(7) Decrease variable attenuator by 30 dB and readjust signal generator output to
position recorded in (6) above (reference).
(8) Increase variable attenuator in 10 dB steps for a total of 20 dB. Trace will
decrease in 10 dB 1.0 dB steps on crt. Record error for each 10 dB step.
(9) Maximum cumulative error recorded in steps (5) through (8) will not exceed
2.0 dB over 80 dB range.
(10) Position controls as listed in (a) through (c) below:
(a)
VERTICAL DISPLAY 2 dB/DIV pushbuttons to on.
(b)
FREQUENCY SPAN/DIV control to 20 kHz.
(c)
RESOLUTION BANDWIDTH control to 100 kHz.