Bird Technologies 4314C - Manual (Page 28)

16
Measuring Percentage Of Positive Modulation
To measure the percentage of positive modulation in an amplitude modulation
system, employ the average and peak reading characteristics of the unit since:
By substitution we get:
Where: P P = peak power as read with CW/PEAK switch in PEAK mode.
P
C
= carrier power as read with CW/PEAK switch in CW mode
Or:
And by cancellation:
After determining average and peak readings, find the intersection of the carrier
and peak powers on Figure 6 on page 17 to determine the percentage of posi-
tive modulation.
PercentagePosMod
E
MAX
E
CARRIER
–
E
CARRIER
---------------------------------------------x100 =
PercentagePosMod
P
P
P
C
–
P
C
----------------------------
 
 
 
x100 =
PercentagePosMod
P
P
P
C
-----------
P
C
P
C
----------- –
 
 
 
x100 =
PercentagePosMod
P
P
P
C
----------- 1 –
 
 
 
x100 =