Filter
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Checks and Adjustments
5-10
1705A Spectrum Monitor
6. Check Resolution Filter
REQUIREMENT -- 300 kHz Filter Resolution 200 -- 400 kHz. 10 kHz
Filter Resolution 20 kHz or less. Filter through gain matches ±2dB.
a. Adjust the leveled sine wave generator Amplitude for a 5 Division signal
amplitude.
b. CHECK -- that the marker width 0.6 Divisions down from the top of the
signal is 3 Divisions, ±1 Division.
c. Changeresolutionto10kHz.
d. Set SWEEP SPEED fully counterclockwise.
e. CHECK -- that the marker width 0.6 Divisions down from the top of the
signal is ≤2 minor Divisions.
f. CHECK -- that the 10 kHz marker amplitude matches the highest point
of the 300 kHz marker amplitude within 1 minor Division, when
switching between 300 KHZ and 10 KHZ RESOLUTION.
7. Check 70 MHz Gain and Flatness
REQUIREMENT -- Incremental Amplitude Accuracy ±4dB/70MHz.
Flatness ±1 minor Division from 70 MHz to either 50 or 90 MHz.
a. Set SPAN/DIV to FULL.
b. Set RESOLUTION to 300 kHz.
c. Set SWEEP SPEED fully clockwise.
d. Set the leveled sine wave generator Frequency to 70 MHz, the Ampli-
tude Multiplier to X1, and the Amplitude to 0.5 (--2 dBm).
e. CHECK -- for a marker amplitude change of 2 Divisions, ±2 minor
Divisions when switching the leveled sine wave generator Amplitude
Multiplier between 0.01 and 0.1 (a 20 dB change).
f. Set the leveled sine wave generator Amplitude Multiplier to 0.01 and
Amplitude to 0.5 (--42 dBm).
g. Position the tip of the marker to exact crt center with the HORIZONTAL
and VERTICAL POSITION controls.
h. Set the leveled sine wave generator Frequency to 50 MHz.
i. CHECK -- that the tip of the marker is on the crt center line, ±1 minor
Division (vertically).
j. Set the leveled sine wave generator Frequency to 90 MHz.