Question

Find the bandwidth for the following situations if we need to modulate a 5-KHz voice.

a. AM

b. PM (setß=3)

c. PM (set p=1)

Answer 1

Given the frequency of the voice signal -

$(f)=5kHz$

a) Bandwidth of the amplitude modulation $B_{AM}=2B$

$=2\times 5kHz$

$=10kHz$

b) Bandwidth required for the phase modulation

$B_{PM}=2(1+\beta)B$

Now, substituting the values,

=$2(1+3)\times 5 kHz$

$=40kHz$

c) Bandwidth required for the phase modulation,

$B_{PM}=2(1+\beta)B$

Now, substituting the values,

$=2(1+1)\times 5kHz$

$=20kHz$