HP 8340B Manual page 70

4-15. AMPLITUDE MODULATION TEST (Cont'd)
It is important that the mixer be connected directly to the LO's RF Output
connector.
Procedure
AM SENSITIVITY AND ACCURACY
1. Connect equipment as shown in Figure 4-19. Connect the mixer LO port at the LOs RF output.
Connect the Power Sensor to the power meter. Allow a one hour warm up time. Set the power
meter's calibration factor switch to include 1.5 GHz, then zero and calibrate the power meter.
Connect the power sensor to the DUT's RF output.
2. On the DUT, press [INSTRPRESET] [CW] [1]
enter [5] [dBm].
[—1
The function generator output impedance is 50 Ohms and its output indi-
cation accuracy assumes a 50 Ohm load. The DUT's AM input imped-
ance is 600 Ohms; therefore, a high impedance DVM is used to measure
and set the function generator output level.
3. Zero the power meter as follows:
With power applied to the sensor, press the power meter RANGE HOLD. Press the DUT's [RF]
key to turn the RF OFF. Zero the power meter. Press the [RF] key to turn the RF ON.
4. Using the DVM as an indicator, set the function generator to output 0 Vdc (If the function gener-
ator being used does not have this feature, use a dc power supply). Press the DUT's [AM] key
(AM ON). Note the power meter indication.
S. Simulate
~t30O/o
on the DVM. The power meter indication should increase by 2.18 to 2.38 dB from the value noted
in step 4.
(0.3
20 log (1
i-
to
20 log (1 + (0.3 + (0.OS times 0.3)))
6. Simulate
~30o/o
on the DVM. The power meter should decrease by 2.91 to 3.29 dB from the value noted in step 4.
20 log (1 ±(—0.3
to
20 log (1 + (—0.3 + (0.05 times —0.3)))
The DUT's test power levels are selected to avoid power meter range
changes at the +30 and —30% modulation settings.
HP 8340B/41B
modulation by setting the function generator output to +0.3 volts dc as indicated
—
times 0.3)))
(0.OS
=
=
modulation by setting the function generator output to —0.3 volts dc as indicated
(0.OS times —0.3)))
—
NOTE
[.1
[5] [GHz].Press the [POWER LEVEL] key and
NOTE
2.18 dB
2.38 dB
—2.91 dB
=
—3.29 dB
=
NOTE
Performance Tests 4-73