Chapter 10 417
Analyzer Options and Block Diagrams
Tracking Generator 8593E, 8594E, 8595E, 8596E Option 010
NOTE The 600 MHz drive signal should be −8 dBm ±3.5 dB. The 1st LO signal
should be +16 dBm ±2 dB.
If power sweep is not functioning properly
Power sweep is accomplished by summing an attenuated SWEEP
RAMP signal with the PWR_LVL signal. The SWEEP_RAMP is
attenuated using the 12-bit power sweep DAC. The power sweep DAC
output is then fed to a summing amplifier where it is summed with the
power level DAC output to yield the PWR_LVL signal.
1. If some power sweep ranges do not appear to work properly, the fault
is probably the power sweep DAC on the A10 Tracking Generator
Control assembly. Check the operation of the power sweep DAC as
follows:
a. Monitor A10U9 pin 7 with an oscilloscope. Connect the ground
lead of the oscilloscope to A10TP1. (Refer to the schematic for the
A10 Tracking Generator Control assembly.) Trigger the
oscilloscope using the analyzer HIGH SWEEP IN/OUT signal on
the rear panel.
b. Set the analyzer by pressing the following keys.
FREQUENCY
CENTER FREQ, 300, MHz
SPAN, 0, Hz
BW, 300, kHz
AUX CTRL
Track Gen
SRC POWER , −10, dBm
SRC PWR SWEEP, 10, dB
c. The amplitude of the positive-going ramp displayed on the
oscilloscope should be approximately 7.8 V.
d. Change the SRC PWR SWEEP setting to any value between 1 and
11 dB. The ramp amplitude displayed on the oscilloscope should
be 780 mV per dB of the SRC PWR SWEEP setting.
NOTE Although the source power sweep may be set to a 12.75 dB sweep
width, the power sweep function is only warranted to have a 11 dB
sweep width.
2. Perform the Vernier Accuracy performance test. See the calibration
guide for your instrument. If this test fails, refer to “If vernier
accuracy is out of tolerance.” earlier in this section.
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