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4. If a -35
dBm
signal does not appear, the cal oscillator is probably at fault.
Parameters
Adjusted
The following IF parameters are adjusted in the sequence listed:
1. Amplitude
A. Video Offsets: analog (using log amplifier video offset DAC) and digital (applying
stored constant to all readings)
1. Linear Scale Offset
2. Log Scale Offset
a.
Wideband
and Narrowband modes
b. 0 to 60 dB range in 10 dB steps
c. 10 dB/division and 2 dB/division (log expand) modes
B. Step Gains (A5 IF Assembly)
1. First Step Gain for 16 different DAC settings
2. Second Step Gain for 16 different DAC settings
3. Third Step Gain for 0, 15, and 30 dB attenuation relative to maximum gain
4. Fine Attenuator for 32 evenly-spaced DAC settings
C. Log Amplifier Slopes and Fidelity
1.
Wideband
(RES BW 300 kHz through 2 MHz) and Narrowband modes (RES BW
300 Hz through 100 kHz)
2. 10 dB/division and 2 dB/division (log expand) modes
D. Linear Scale Gains
-
On the log amplifier assembly (P/O A4)
E. Peak Detector Offsets (both positive and negative peak detectors with respect to
normal sample path used by Auto IF Adjust)
2. LC Bandwidths
A. 300 kHz resolution bandwidth center frequency, bandwidth, and gain
B. 1 MHz resolution bandwidth center frequency, bandwidth, and gain
C. 2 MHz resolution bandwidth gain
D. 100 kHz resolution bandwidth center frequency, bandwidth, and gain
E. 30 kHz resolution bandwidth center frequency, bandwidth, and gain
F. Gain of all resolution bandwidth relative to the 300 kHz RES BW
9-10
IF Section