HP 8901B Operation And Calibration Manual page 289

Operation
Model 8901B
100
A
n
z
v)
+
80
-
5
0
a
W
O
60
a
a
L
= )
40
Y
I -
u
v)
W
m
0
I-
z
0
s
Y
20
Y
n
1 10
1000
10
000
Nomograph for Calculating Percentage of
Npk
to be Subtracted
from
(s
+
N)pk to obtain
Spk
(Sinewave Modulation Only)
EXAMPLE
An RF signal is applied
to
the Modulation Analyzer. The modulation rate is 1
kHz
and the peak
modulation is to be measured in
a
15
kHz
post-detection bandwidth. To measure the peak AM depth
and correct for the effects of residual noise on the modulation:
1. Measure the peak modulation depth, (S
+
N ) p k :
LOCAL
(keystrokes)
$@
(program codes)
AU M 1
D 1 1 2
Measurement
L T L
Filter
Detector
~
~~ ~
For the purposes of subsequent calculations, assume the displayed AM is 30.80%.
3-192 Residual Noise Effects