
11.
Down/Up
Converter
Adjustments
Reference
IF-Display Section
A4A6
Down/Up Converter
Related
Performance
Test
Resolution Bandwidth Switching Uncertainty Test
Description
The CAL OUTPUT signal is connected to the RF INPUT connector of
the spectrum analyzer and controls are set to display the signal in a
narrow bandwidth. A marker is placed at the peak of the signal to
measure the peak amplitude. The bandwidth is changed to a wide
bandwidth and the Down/Up Converter is adjusted to place the peak
amplitude of the signal the same as the level of the narrow bandwidth
signal. Optionally, the input signal is removed and the IF signal is
monitored at the output of the Bandwidth Filters using a spectrum
analyzer with an active probe. The 18.4 MHz Local Oscillator and all
harmonics are then adjusted for minimum amplitude.
HP
55024A
HIGH
FREQUENCY
PROBE
Equipment
Procedure
SPECTRW
I
ANALYZER
MA*TPJ
SPECTRUM
ANALYZER
PROBE
PWER
SUPPLY
Figure 3-50. Down/Up Converter Adjustments Setup
Spectrum Analyzer
.........................................
HP 8566B
Active Probe
..............................................
HP 85024A
Probe Power Supply
........................................
HP 1122A
Note
Adjustment A4A6AlR29 WIDE GAIN adjusts the amplitude of the
21.4 MHz Bandwidth Filters (3
kHz
through 3 MHz) relative to the
amplitude of the 3 MHz Bandwidth Filters (1
kHz
through 10 Hz).
Perform Adjustment Procedure 6, “Log Amplifier Adjustments,”
(steps 1-12) Adjustment Procedure 8, “21.4 MHz Bandwidth Filter
Adjustments,” and Adjustment Procedure 7, “3 MHz Bandwidth Filter
Adjustments” to ensure that the amplitudes of the bandwidth filters
are optimized before adjusting A4A6AlR29 WIDE GAIN (steps 14-17).
3-100
Adjustments
Commentaires sur ces manuels