HP 8562E, Service Manual

Page: 445 / 482

2. On the HP 85623, press and
MIXER.
The voltage on the DVM
should measure approximately Vdc (TTL high).
3. On the HP 85623, press and MIXER. The voltage on the DVM
should measure approximately 0 Vdc (TTL low).
4. Connect the positive lead of a DVM to pin 13 (LSID). The signal measured
turns on the SIG ID oscillator.
5. On the HP 85623, press SIG ID ON (if present),
6. Subsequent pushes of should cause the signal measured on the DVM to toggle
between TTL high and low levels.
7. Connect an oscilloscope probe to pin 7 (LRDIR) and the probe ground lead to
pin 6. The signal measured controls the flatness compensation circuit.
8. On the HP 85623, press and set the (SPAN) to 1 MHz.
9. Set the oscilloscope for the following settings:
Amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sweep time
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10. The waveform should be at a TTL high during part of the retrace period and a TTL low
during the sweep (about 50 ms).
Refer to function block F on Al5 RF Section Schematic Diagram (sheet 4 of 4) in the
HP 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 HP 85623 is set to SIC ID the SIG ID Oscillator turns on
during alternate sweeps.
1. Set the HP 85623 to the following settings:
Trigger . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . single sweep
SIG ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . on
2. Use an active probe with another spectrum analyzer to measure the signal level at
3. On the HP 85623, press With each press of the analyzer alternates
between the following two states:
State 1:
pin 13 (LSID)
SIG ID Oscillator
Signal at
TTL low
ON
298 MHz (at least
State 2:
pin 13 (LSID)
SIG ID Oscillator
3rd LO Driver Amplifier
TTL high
O F F
Provides LO for Double Balanced Mixer
RF Section 12-19