HP 8340B Manual page 71

4-15. AMPLITUDE MODULATION TEST (Cont'd)
7. Press the DUT's [POWERLEVELI key and enter
OFF. Repeat steps 3 through 6 for this power setting.
8. Press the DUT's [CW] key and enter [4]
power meter's calibration factor switch to include 4.5 GHz. Repeat steps 3 through 6 for DUT
power settings of —S and ±5 dBm.
AM FREQUENCY RESPONSE AND BANDWIDTH
9. Disconnect the power sensor and connect the DUT's RF output to the 20 dB attenuator.
10. On the DUT, press [CW] [1]
[INSTRPRESET] [CW][1]
output may be unleveled; this will not affect the test.) The IF frequency is now 50 MHz.
For best accuracy in the Amplitude Modulation test, the Local Oscillator
drive to the mixer should be
11. Set the function generator for a sine wave at a reference frequency of 1 kHz at 0.2121 Vrms (0.3
times 0.707)
±
range. Set the modulation analyzer input frequency to 50 MHz (by pressing FREQ 50 MHz), then
press AM and AVE. The modulation analyzer should indicate about 21%. Note the DVM indication.
12. Press the dB key. As the modulating frequency is changed, the modulation analyzer will indicate
the flatness in dB relative to the 1 kHz reference.
13. Set the function generator to 100, 200, SOO Hz then 1,2,5, and 10 kHz. Check the DVM indication
and adjust the level of the modulating signal at each frequency to eliminate any flatness error of
the function generator. Observe the flatness indication on the modulation analyzer. The flatness
indication should be
14. Check the AM bandwidth by setting the function generator to 100 kHz. Adjust the function gener-
ator output level to the value noted in step 11. The modulation analyzer should indicate
AM DEPTH
15. Set the function generator to 1 kHz. Set the modulation analyzer to indicate percent modulation by
setting the controls as follows:
AUTOMATIC OPERATION
AM
RATIO
RATIOdB
PEAK
Increase the function generator output amplitude to obtain >90% modulation depth.
16. Repeat steps 11 through iS at DUT RF frequencies of 3, 9,15, and, if the DUT is an HP 8340B, 22
GHz. Make sure LO CW frequency is always 50 MHz below the DUT frequency.
4-74 Performance Tests
[.1
[5] [GHz], [POWERLEVEL] [0] [dBm]. On the LO, press
[4] [5] [GHz],[POWERLEVEL] [1][0] [dBin]. Press PEAK (ON). (The
[.]
>
0.05 Vms. For example: 0.2S Vms, as indicated on the DVM, would fall in this
0.20 dB.
= ±
%
[-4-] [ 51
[dBm].
[5] [GHz].Press the [AM] key to turn AM OFF. Set the
[.]
NOTE
dBm.
-1-4
Press the [AM] key to turn AM
= —3dB.
HP 8340B/41B
ON
ON
OFF
OFF
-1-