

Homework 9  Angular Transmission Modulation
Problem 1.
If a frequency modulator produces 5KHz of frequency deviation for a 10V modulating
signal, determine the deviation sensitivity. How much frequency deviation is
produced for a 2V modulating signal.
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Problem 3.
Determine (a) the peak frequency deviation, (b) the carrier swing, and (c) the
modulation index for an FM modulator with deviation sensitivity K_{1} = 4KHz/V
and a modulating signal v_{m}(t) = 10 sin( 2 pi 2000 t ). What is the peak
frequency deviation produced if the modulating signal were to double in amplitude?
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Problem 10.
An FM transmitter has a rest frequency equal to 96MHz and a deviation sensitivity
K_{1} = 4KHz/V. Determine the frequency deviation for a modulating signal
v_{m}(t) = 8 sin ( 2 pi 2000 t), and the modulation index.
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Problem 12.
For an FM modulator with a 40KHz frequency deviation and a modulating signal frequency
of 10KHz, determine the bandwidth using both a Bessel table and Carson’s rule.
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Problem 13.
For an FM modulator having an unmodulated carrier amplitude V_{c} = 20V, a
modulation index m = 1, and a load resistance R_{L} = 10ohms, determine
the power in the modulated carrier an each side frequency, and sketch the power
spectrum for the modulated wave.
{ Solution }
Engineering key words: modulation, RF spectrum, power and gain, waveform, Bessel table,
Carsons Rule, amplitude, bandwidth, sideband, frequency deviation, sensitivity, FM,
loads, signals, angular modulation, phase angle, transmit.
