Agilent Technologies 856290216 - page 235

RF Path Fault Isolation
RF path fault isolation checks high-band RF paths. (Automatic fault isolation checks the
low-band RF path.) An external microwave source with a frequency range of 5 GHz to
13.2 GHz is required. The source is not controlled over HP-IB. The user is prompted by the
TAM to set the source to 5 GHz at -10 dBm. (The TAM expects -10 dBm at the input of
the spectrum analyzer; the amplitude at the source output may have to be higher to account
for cable loss.)
The source also provides a signal for high band. The TAM checks the operation of the A9
input attenuator. The TAM checks the A10 YIG-tuned filter/mixer at 5 GHz. If no signal is
present, the TAM will use the 298 MHz SIG ID oscillator, if present, as is done in AFI.
Calibration Oscillator Troubleshooting Mode
The cal osc troubleshooting mode enables front-panel control of the cal oscillator on the
A4 assembly. The cal oscillator can be fixed-tuned to three different frequencies. The cal
oscillator may also be set to one of four sweep widths, centered at 10.7 MHz. Fixed-tuned
settings:
11.5 MHz
10.7 MHz
9.9 MHz
Sweep-width settings:
20 kHz
10 kHz
4 kHz
2 kHz
The cal osc troubleshooting mode sends the cal oscillator output (-35 dBm) to the A5 IF
assembly. On the A5 IF assembly all crystal filter poles are shorted, all LC poles are enabled,
and the 15 dB attenuator is disabled. Signals from the RF section are attenuated as much as
possible.
7-16 General Troubleshooting