
Model 8640B
TM 9-4938-601-14-7&P
PERFORMANCE TESTS
4-20. SINGLE SIDEBAND BROADBAND NOISE FLOOR (Cont'd)
DESCRIPTION:
A spectrum analyzer is used to measure the broadband noise floor (a reference signal generator and a mixer are used to
down-convert the test Signal Generator's RF output and noise to within the range of the spectrum analyzer). A reference
level is set on the analyzer with a 5 kHz signal, the signal is changed to 500 kHz and removed from the analyzer with a
filter, and the broadband noise floor is measured.
Figure 4-7. Single Sideband Broadband Noise Floor Test Setup
EQUIPMENT:
Reference Signal Generator .....................................................................................HP 8640A
Mixer ......................................................................................................................HP 10514A
15 kHz Low-Pass Filter ................................................................................ CIR-Q-TEL 7 Pole
10 dB Step Attenuator................................................................................................ HP 355D
40 dB Amplifier .............................................................................................. HP 08640-60506
Spectrum Analyzer ...............................................................................HP 141T/8552B/8556A
PROCEDURE:
1.
Connect equipment as shown in Figure 4-7 after setting test Signal Generator's controls as follows:
Meter Function ..................................................................................................................................... LEVEL
COUNTER MODE:
EXPAND ................................................................................... Off
LOCK........................................................................................ Off
Source ..................................................................................... INT
AM............................................................................................................................................................ OFF
FM............................................................................................................................................................ OFF
RANGE ...................................................................................................................................... 256-512 MHz
FREQUENCY TUNE .................................................................................................................. 500.000 MHz
OUTPUT LEVEL....................................................................................................... -7 dBm (Vernier max cw)
RF ON/OFF................................................................................................................................................ON
4-18
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