15-5
Diagnostics Theory
RF_DIAGS
RF_DIAGS
Reference
This test checks the A15 Reference Section assembly.
10 MHz Lock Detector State
The10 MHz VCO is measured using the counter; however, the counter uses the reference
sothe measurement is an indication that the counter is working. This verifies that both the
reference and the count signal are reaching the counter.
1 GHz Oscillator Lock Detector State
The 1 GHz VCO lock detector is checked for lock.
1 GHz and 500 MHz Level Detectors
The1 GHz and 500 MHz level detectors are checked to test for signals from these outputs.
10 MHz Fine and Coarse DACs State
The 10 MHz VCO is checked for locks at both ends of the tune DAC range.
NSM and Pre-Modulation Filter
This test checks the A5 Premod Filter and NSM assembly.
NSM Clock Detector State
The presence of a clock is checked.
Pre-Modulation Filter Clock Detector State
ThePremod filter clock is checked for lock with both a clock present and not present. The
front panel AUDIO OUT is used as a test clock. It is connected to the front panel
MODULATION CLOCK input.
DAC and Up-Converter
This test checks the A27 DAC/Upconverter assembly.
Detector Output Level
Thistest checks for an output at several frequencies using the voltmeter at the AUX4_VM
output.