Agilent Technologies 8564EC, Service Manual

Page: 486 / 512

Chapter 12 625
RF Section
A15 RF Assembly
8. On the spectrum analyzer, press
PRESET
and set the
SPAN
to 1 MHz.
Set the oscilloscope for the following settings:
Amplitude scale ........................................................... 2 V/div
Sweep time .............................................................. 20 ms/div
9. The waveform should be at a TTL high during part of the retrace
period and a TTL low during the sweep (about 50 ms).
SIG ID Oscillator (Option 008)
Refer to function block F on A15 RF Section Schematic Diagram in the
8560 E-Series Spectrum Analyzer Component Level Information.
SIG ID is available only with Option 008. The SIG ID Oscillator
provides a shifted third LO (approximately 298 MHz) to distinguish
true signals from false signals (such as image or multiple responses).
When the spectrum analyzer is set to
SIG ID ON
, the SIG ID Oscillator
turns on during alternate sweeps.
1. Set the spectrum analyzer to the following settings:
Trigger ............................................................ single sweep
SIG ID .............................................................................. on
2. Use an active probe with a second spectrum analyzer to measure the
signal level at A15X602.
3. On the spectrum analyzer, press
SGL SWP
. With each press of
SGL SWP
, the analyzer alternates between the following two states:
State 1:
A15J901 pin 13 (LSID)....................................... TTL low
SIG ID Oscillator ........................................................ ON
Signal at A15X602..298MHz
±
50 kHz (at least +1 dBm)
State 1:
A15J901 pin 13 (LSID)......................................TTL high
SIG ID Oscillator .......................................................OFF
3rd LO Driver Amplifier .... Provides LO for Double Balanced Mixer
4. With the SIG ID oscillator on, measure the frequency at A15X602
with a frequency counter and an active probe. If the frequency is not
298 MHz
±
50 kHz, refer to the “14. Signal ID Oscillator Adjustment
(serial prefix 3517A and below)” on page 151 . (There is no
adjustment for instruments with A15 RF assembly 08563-60084 or
greater.)