TM 11-6625-2781-14&P-2
Section IV
PERFORMANCE TESTS (cont'd)
Frequency Response (cont'd)
5. To check the analyzer frequency response from 1 MHz to 10 MHz, connect the test setup as shown in Figure 4-10.
Make the following control settings:
ANALYZER:
BANDWIDTH ................................ ................................ ................................ ................................ ................. 30 kHz
SCAN WIDTH PER DIVISION ................................ ................................ ................................ ........................ 1 MHz
RANGE MHz ................................ ................................ ................................ ................................ ..................... 0-11
651B
FREQUENCY ................................ ................................ ................................ ................................ ....................... 10
RANGE................................ ................................ ................................ ................................ .............................. X1M
OUTPUT ATTENUATION ................................ ................................ ................................ ............................ -30 dBm
6. Adjust the analyzer FREQUENCY control to place the 10 MHz signal on the far right (+5) graticule line. Adjust the
651B signal level to obtain the same display amplitude as measured in step 4. Tune the 651B between 10 MHz and
1 MHz; frequency response should be between 6.6 and 7.4 linear divisions. If the response peaks above 7.4
divisions, reset the 651B level at that frequency and continue checking the frequency response in the steps below.
6.6
7.4 DIV
7. Repeat step 6 to check 1 MHz to 100 kHz setting the analyzer BANDWIDTH to 10 kHz and SCAN WIDTH PER
DIVISIONS to .1 MHz. Set 651B to X100K range.
6.6
7.4 DIV
8. Repeat step 6 to check 100 kHz to 10 kHz setting the analyzer BANDWIDTH to 1 kHz, SCAN WIDTH PER
DIVISION to 10 kHz, SCAN WIDTH PER DIVISION to 10 kHz, and FREQUENCY to place the LO signal on the far
left (-5) graticule line. Set 651B to X10K range.
6.6
7.4 DIV
9. Repeat step 6 to check 10 kHz to 1 kHz setting the analyzer BANDWIDTH to .1 kHz, SCAN WIDTH PER DIVISION
to 1 kHz, FREQUENCY to place the LO signal on the far left (-5) graticule line. Set 651B to X1K range.
6.6
7.4 DIV
10. If the 651B had to be readjusted per step 6, then repeat the response test from 10 MHz to 110 MHz by setting the
608E/F amplitude at 10 MHz to correspond with the displayed amplitude of the 651B at 10 MHz, and repeat steps 1-
3.
4-27. Average Noise Level
SPECIFICATION:
<-110 dBm with 10 kHz IF bandwidth.
DESCRIPTION:
Average noise level is checked by observing the average noise power level of the analyzer with the instrument vertically
calibrated and no signal input. The test is made using a 10 kHz IF bandwidth.
1. Check the analyzer to make sure it is vertically calibrated. Refer to Paragraph 4-12 for instructions.
2. Make the following analyzer control settings.
RANGE MHz ................................ ................................ ................................ ................................ ..................... 0-110
FREQUENCY................................ ................................ ................................ ................................ ............... 110 MHz
BANDWIDTH ................................ ................................ ................................ ................................ .................. 10 kHz
4-15
