Phase, Recorder Gain And Pattern Shape Adjustments - HP 8414A Operating And Service Manual

Section V
Adjustment Procedures
Model 8414A
ADJUSTMENT PROCEDURE
5-10. PHASE, RECORDER GAIN, AND PATTERN SHAPE ADJUSTMENTS.
DESCRIPTION:
A CW signal is applied to the Network Analyzer to provide a reference channel input signal to the 8414A
and for 8410A Network Analyzers so that the Network Analyzer unblanks the 8414A display. A 280-kHz
signal is applied to the 8414A amplitude channel through the Network Analyzer test channel output
connector. These two signals cause a circle to be displayed on the 8414A. The radius of this circle is
adjusted to the radius of the outer graticule circle by adjusting the amplitude of the 280-kHz signal. The
8414A PHASE ADJUST control, RECORDER GAIN ADJUST control and PATTERN SHAPE control are
adjusted for the best circle.
PROCEDURE:
NOTE
Perform paragraph 5-9, TRACE ALIGNMENT AND VERTICAL GAIN
ADJUSTMENT before performing this adjustment.
a. Connect equipment as shown in Figure 5-2.
b. Set the sweep oscillator for single frequency operation at any frequency within the frequency
range of the Network Analyzer.
c. Set the Network Analyzer to phase lock to the applied signal and adjust the sweep oscillator RF
amplitude for a Network Analyzer reference channel level meter indication in the middle of the operate
region.
d. Press and hold the 8414A BEAM CTR pushbutton and adjust the HORIZ POS and VERT POS
controls to locate the dot in the center of the Polar Display.
e. Set the Network Analyzer test channel gain controls for
minimum
gain. For 8407A Network
Analyzers set display reference control switches down.
f. Adjust the oscillator connected to the Network Analyzer test channel output as follows:
1. Adjust the frequency to obtain the best circle (slight flicker in 8414A display).
2. Adjust the output amplitude to obtain a circle whose radius is equal to the radius of the
CRT's outer graticule circle.
NOTE
It may be necessary to adjust the HORIZ POS and VERT POS controls to
locate the average of the trace over the outer graticule circle.
g. Adjust A2R21 (Phase Adjust), A1R37 (Recorder Gain Adjust) and A3R20 (Pattern Shape) for the
best circle. The trace must be less than 3 mm from the outer graticule circle around the entire circle.
5-6