User`s guide

92 Chapter 3
Operation
Using 8561A/62A/62B Spectrum Analyzers
Operation
7. Change the spectrum analyzer center frequency to the value indicated below, then save
this setting in an unused register:
for an 11974A: 40 GHz
for an 11974Q: 50 GHz
for an 11974U: 60 GHz
for an 11974V: 75 GHz
8. 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: “40 GHz SET”
for an 11974Q: “50 GHz SET”
for an 11974U: “60 GHz SET”
for an 11974V: “75 GHz SET”
9. Repeat step 5 through step 8 until green lights are lit at both frequencies without any
additional adjustments.
Operation
Band Selection
1. If necessary, mate the 11974 to the spectrum analyzer being used for preselected
external mixing by using the Frequency Tracking Calibration procedure above.
2. Use the following key sequence to enter the external mixing mode and to select the
desired band of operation.
EXT
FULL BAND
Use the ⇑ or ⇓ key until the desired band is reached.
NOTE The above band-selection key sequence must be used to enter the external
mixing band of operation. Do not enter in the center frequency of the band
directly.
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.)