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using trigonometric identity, | using trigonometric identity, | ||
| − | <math>cos^2{w_{c}t}=\frac{1}{2}x(t)+\frac{1}{2}x(t)cos{2w_{c}t}</math> | + | <math>cos^2{w_{c}t}=\frac{1}{2}+\frac{1}{2}cos{2w_{c}t}</math> |
| + | |||
| + | <math>w(t)=\frac{1}{2}x(t)+\frac{1}{2}x(t)cos{2w_{c}t}</math> | ||
Revision as of 18:50, 17 November 2008
DEMODULATION FOR SINUSOIDAL AM
$ y(t) = x(t)cos{w_{c}t} $
the original signal can be recovered by modulating y(t) with the same sinusoidal carrier and applying a lowpass filter to the result.
consider,
$ w(t) = y(t)cos{w_{c}t} $
$ w(t) = x(t)cos^2{w_{c}t} $
using trigonometric identity,
$ cos^2{w_{c}t}=\frac{1}{2}+\frac{1}{2}cos{2w_{c}t} $
$ w(t)=\frac{1}{2}x(t)+\frac{1}{2}x(t)cos{2w_{c}t} $
