2-55
MODULATION INDEX is the ratio of the maximum frequency difference between the modulated
and the unmodulated carrier, or between the deviation frequency and the modulation frequency.
The number of SIGNIFICANT SIDEBANDS and the modulating frequency will determine the
bandwidth of the fm wave. The number of significant sidebands can be determined from the modulation
index.
MODULATION
INDEX
SIGNIFICANT
SIDEBANDS
.01
2
.4
2
.5
4
1.0
6
2.0
8
3.0
12
4.0
14
5.0
16
6.0
18
7.0
22
8.0
24
9.0
26
10.0
28
11.0
32
12.0
32
13.0
36
14.0
38
15.0
38
The REACTANCE-TUBE MODULATOR is frequency modulated by using a reactance tube in
shunt with the tank circuit.
