d. Adjust L444 (wide band amplifier), T464, T454, C435 and
C425 (Fig. 6-24) in the order listed for optimum signal am-
plitude.
e. Adjust L444 for stable 60 MHz oscillator operation.
Resolution Cal R543.
The stable point is midway between the oscillator dropout
points when the core of L444 is turned in and out through
the operating range. (Remove the P6041 or P6040 cable if
j. Check display symmetry through each position of the
connected and reconnect the cable to J100.)
RESOLUTION selector. When these adjustments are correct,
display will remain fairly symmetrical through the range of
f. With 200 MHz signal applied to the RF INPUT as de-
the selector. Remove the 10 probe and return the RESOLU-
scribed in step b, set the DISPERSION to 50 kHz/div, the
TION selector to the fully clockwise position.
RESOLUTION fully clockwise, IF ATTENUTOR for 20 dB, and
adjust the GAIN control for a signal amplitude of 8 divisions.
k. Check the Type 491 resolution bandwidth at the -6 dB
Center the display with the IF CENTER FREQ controls. Tune
point. (This point can be located by switching in the 2
the RF CENTER FREQUENCY if necessary to minimize inter-
and 4 dB IF ATTENUATOR dB switches and noting the dis-
ference from converted signals.
play amplitude.) Bandwidth must equal or exceed 100 kHz
g. Connect a test oscilloscope through a 10 probe to
at the -6 dB point.
pin B of the honeycomb square pin connector. Adjust the
test oscilloscope sensitivity for a display amplitude of ap-
1. If the bandpass is less than 100 kHz in step k, adjust
proximately 6 divisions then adjust the triggering controls for
the 100 kHz Resolution Cal R543 (Fig 2-28) to obtain a
a stable display. See Fig. 6-25. (Test oscilloscope sweep rate
bandpass between 100 kHz and 120 kHz at the -6 dB point.
should be the same as the analyzer sweep rate.)
m. Turn the RESOLUTION control one position counter-
h. Adjust 100 kHz Resol Cal R543 (Fig. 6-28) so the display
clockwise from the fully clockwise position (DISPERSION is
begins to show evidence of over coupling (slight dip in the
50 kHz.) Readjust the GAIN control for a full 8 division
center]. Bandpass response on the analyzer display should
display and check the bandpass at the -6 dB point. Band-
decrease to approximately 60 kHz at the -6 dB point when
pass should decrease to approximately 60 kHz.
the RESOLUTION selector is turned counterclockwise one
step from the fully clockwise position.
n. These adjustments interact. When properly set, the
resolution bandwidth should vary from approximately 100
i. Set, the RESOLUTION selector fully clockwise. Adjust
kHz, with the control in the full clockwise position, to 1 kHz
C504 and C508 (Fig. 6-27) for optimum display symmetry
or less with the RESOLUTION control in the fully counter-
on the test oscilloscope See Fig. 6-25. Adjust C504 for
clockwise position As the DISPERSION is reduced to the 1
the slope of the response and C508 for symmetry. Turn
kHz/div position, the sweep rate must also be decreased
the RESOLUTION selector counterclockwise one step from
to approximately .2 s/div to maintain a symmetrical re-
fully clockwise position. Adjust C601, C604, C607 and C610
for optimum display symmetry and amplitude.
sponse.
6-25
