User`s guide

Chapter 4 127
Performance Tests
4. Displayed Average Noise Level
Performance Tests
CAUTION Turn off the ac power on the 11974-60028 Preselector Power Supply prior to
connecting or disconnecting it from the 11974.
On the 11974 rear panel, set the instrument select switches to the
appropriate settings before applying power to the 11974.
7. Set the spectrum analyzer to the appropriate millimeter band by using the following
controls:
for an 11974A:
SHIFT ⇑ ⇑
for an 11974Q: SHIFT ⇑ ⇑ ⇑
for an 11974U: SHIFT ⇑ ⇑ ⇑ ⇑
for an 11974V: SHIFT ⇑ ⇑ ⇑ ⇑ ⇑
8. Set the spectrum analyzer controls as follows:
FREQUENCY SPAN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0 Hz
RES BW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Hz
VIDEO BW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Hz
ENTER dB/DIV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 dB
9. Set the spectrum analyzer center frequency by pressing
CENTER FREQUENCY and
entering the corresponding frequency value for the band listed below:
for an 11974A: 26.5 GHz
for an 11974Q: 33 GHz
for an 11974U: 40 GHz
for an 11974V: 50 GHz
10.Set the conversion loss to the value recorded for this frequency in Table 4-7 on page 140
by pressing
SHIFT, 5, and MHz, and entering the conversion loss value from Table 4-7 on
page 140. Press
dB to terminate the entry. Record this value in Table 4-10 on page 146.
11.Set the spectrum analyzer reference level by pressing
REFERENCE LEVEL and entering
the corresponding value for the band listed below:
for an 11974A:
−80 dBm
for an 11974Q:
−80 dBm
for an 11974U:
−80 dBm
for an 11974V:
−80 dBm
12.On the spectrum analyzer, press
SHIFT, VIDEO BW, 10, and Hz to activate the video
average function to average 10 traces.
13.After the video average counter reaches 10, press MARKER
NORMAL and
PEAKSEARCH. The marker amplitude is the displayed average noise level.