User`s guide

Chapter 3 91
Operation
Using 8561A/62A/62B Spectrum Analyzers
Operation
Frequency Tracking Calibration
Use this procedure to align the frequency of the 11974 tracking filter to the tuned
frequency of the spectrum analyzer. Follow this procedure anytime that the 11974 is
connected to a different spectrum analyzer. Periodically check the calibration.
1. Set the 11974 rear-panel switches 8563/61/60 and LEDS to the ON position, and the
other two switches to the OFF position, in order for the 11974 to properly scale the tune
ramp of the spectrum analyzer.
2. Enter the full-band selection mode by using the following key sequence:
EXT
FULL BAND
Use the ⇑ or ⇓ key until the desired band is reached.
3. Apply a frequency offset of 621.4 MHz by using the following key sequence:
FREQUENCY
OFFSET
Enter 621.4 and terminate with MHz. (An F should appear at the left side of the
display screen to indicate that an offset is applied.)
4. Set the spectrum analyzer to zero span by pressing
SPAN ZERO SPAN.
NOTE Due to the repetitive nature of this procedure, it may be helpful to save the
center-frequency settings in unused state registers as indicated in step 5 and
step 7.
5. Set the spectrum analyzer center frequency by pressing
FREQUENCY CENTER FREQ and
entering the corresponding value for the mixer listed below, then save this setting in an
unused register.
for an 11974A: 26.5 GHz
for an 11974Q: 33.0 GHz
for an 11974U: 40.0 GHz
for an 11974V: 50.0 GHz
6. On the rear-panel of the 11974, adjust the corresponding potentiometer for the mixer
listed below until one or both of the green LEDs are lit.
for an 11974A: “26.5 GHz SET”
for an 11974Q: “33.0 GHz SET”
for an 11974U: “40.0 GHz SET”
for an 11974V: “50.0 GHz SET”