HP 8591C User Manual

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Test Descriptions
Depth of Modulation Test Description
Changes the amplitude
scale and span of the
analyzer
Measures the minimum
level and the maximum
level and calculates the
percentage of AM
modulation depth
The amplitude scale is changed from logarithmic (dB) to linear (volts) and
the span is set to 0 Hertz to demodulate the signal and display time domain
characteristics.
The analyzer measures the minimum level and the maximum level.
The minimum level corresponds to the vertical interval test signal
(VITS) white level and the maximum level corresponds to the horizontal
synchronization-pulse (H-sync) level. The ratio of the minimum level (the
VITS white level) to the maximum level (the H-sync pulse level) subtracted
from a value of 1 and multiplied by 100 gives the percentage of modulation:
[
l- minimum x 100 = %AM
maximum
1
Figure 2-27 shows the analyzer measuring the minimum and maximum levels.
MKR 3 9750 msec
AT 10 dB
10.314
mV
I I I I I I I
CENTER 67.275
MH
Z SPAN 0Hz
#RES BW 10 MHz #VBW 1 MHz #SWP 30.0 msec
TV
LINE
#
STOP
MEAS
MORE
INFO
MAIN
MENU
Figure 8-9. Measuring the Depth of Modulation
The depth of modulation result is displayed at the bottom of the screen.
8-29

HP 8591C Specifications

General

Brand	HP
Model	8591C
Category	Measuring Instruments
Language	English