Fluke 6080A Service Manual page 76

PERFORMANCE TESTS
PROCEDURE:
1. Internal Modulation Oscillator Frequency Test
2. Internal Modulation Oscillator Level and Distortion Test
3. AM Accuracy and Distortion Test
4-18
The following procedures must be performed in the order described
below to ensure that the proper equipment is connected and appropriate
programs are enabled.
a. Connect the UUT MODULATION OUTPUT to the frequency counter input.
b. Program the UUT to SPCL 909.
c. Program the UUT for 90% INT AM at a 1-kHz rate and a level of 0 dBm.
d. Verify that the counter reads 1 kHz ± 0.1 Hz.
e. Program the UUT to the following modulation frequencies and verify the
programmed frequency ± 0.1 Hz: 10, 100 Hz, 10 kHz and 100 kHz.
a. Connect the UUT MODULATION OUTPUT to an RMS voltmeter.
b. Terminate the RMS voltmeter with a 600-ohm resistor.
c. Program the UUT to 1 volt peak modulation output and 1-kHz rate.
d. Verify the level as .707 volts ± 1% on the RMS voltmeter.
e. Repeat step d at programmed levels of .2, .5, and 1.5 volts peak (Multiply the
RMS value by 1.414 to get the peak value).
f. Program the UUT Mod Oscillator Level to 1V RMS and the Mod Oscillator
Frequency to 10 kHz.
g. Connect the UUT Modulation Output to the input of the distortion analyzer.
The total harmonic distortion (THD) should be less than 2%.
a. Measure the mean AM depth, (+PEAK plus -PEAK)/ 2, using the modulation
analyzer. Refer to Table 4-5 for AM test conditions.
b. Program the UUT for a frequency of 640 MHz, 0-dBm level, INT AM at 50%
AM depth and a modulation rate of 1 kHz.
c. Connect the modulation output of the modulation analyzer to the input of the
distortion analyzer.
d. Verify that the mean AM depth (+PEAK plus -PEAK)/2 is between 43.0 and
57%.
NOTE