Amplitude Modulation - process of changing the amplitude of
carrier frequencyin proportion with the instantaneous value of the
modulating signal (information)
Two inputs:
1.modulating signal
.carrier signal
AM envelope ! modulated output waveform from an AM modulator
AM "#$%& ! AM "ou'le #ide'and %ull &arrier
.most commonly used.also nown as conventional AM
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nown as emitter modulation 'ecause the carrier is applied to the
'ase and the
modulating signal to the emitter
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2. High-Level Transmitters
A carrier power amplifier and modulating signal amplifiers are
applied
'efore the AM modulator
Trapeoidal patterns*sed for o'serving the modulation
characteristics of AM transmitters such as
coefficient of modulation and modulation symmetry*ses the
&+T of a standard oscilloscope where the modulating signal
input is
applied to the horiontal input and the AM signal input is
applied to the vertical
input with the internal horiontal sweep disa'led
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AM envelopes produced by Complex
Nonsinusoidal signals
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uadrature Amplitude Modulation
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- !orm o" AM #here signals "rom t#o separate in"ormationsources
$i.e. t#o channels% modulate the same carrier "re&uency
at the same time #ithout inter"ering #ith each others
