472 Chapter9
IF Section
Cal Oscillator (P/O A4 Assembly)
300 Hz to 3 kHz Resolution Bandwidth Out of
Specification
1. If the 3 dB bandwidth of one of these filters is incorrect, suspect a
failure of one of the five available sweeps from the cal oscillator
sweep generator (function block Z). These sweeps are generated by
changing the switch settings of A4U803 which routes signals
through A4U802 and A4U804.
2. Disconnect W52 (coax 9) from A4J8.
3. Connect an SMB tee to A4J8, using a short coaxial cable with SMB
connectors.
4. Connect one output of the tee to cable W52 (coax 9).
5. Connect an 85024A active probe to the other output of the tee.
6. Connect the output (type N connector) of the active probe to the
input of the 8566A/B spectrum analyzer.
7.Connect the probe power cable to the 8564EC or 8565EC
spectrum analyzer front panel PROBE POWER connector (you may
need to use a probe power extension cable, 10131B).
8. Press
INSTR PRESET on the 8566A/B and set the controls as follows:
Center frequency ................................................. 10.8MHz
Span ..............................................................................0Hz
Reference level .......................................................−43dBm
Resolution bandwidth ............................................100kHz
Video bandwidth .......................................................10kHz
Sweep time .................................................................50ms
Scale ................................................................ 1dB/division
Sweep .....................................................................SINGLE
9.On the 8564EC or 8565EC spectrum analyzer, press
PRESET
and CAL.
10.Press
FULL IF ADJ. When the display reads ADJUSTING IF:
10 kHz RBW, press
SINGLE on the 8566A/B.
11.The 8566A/B screen illustrates frequency versus time of the output
sweeps of the cal oscillator. See Figure 9-21, “Output Waveform, 10
kHz Resolution Bandwidth.” The slope of the 8566A/B 100 kHz
resolution bandwidth is used to detect frequency changes. Sweeps
that vary (greater than 30 percent) from the normal levels, trigger
error code ERR 581 or ERR 582.
12.Press
FULL IF ADJ. When the display reads ADJUSTING IF: 3 kHz,
press
SINGLE on the 8566A/B.
To Next Page
Loading...
Need help?
General
