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Unformatted text preview: Elementary trigonometric relation: t t t t ) cos( 2 1 ) cos( 2 1 cos cos 2 1 2 1 2 1 -+ + = Using complex notations: 4. Double Side Band Amplitude Modulation: Notations for DSB-SC AM (i.e. no carrier impulse/tone at carrier frequency): Equation Time domain Frequency domain-Message signal:-Carrier:-Modulation (message modulating carrier):-Derivation of frequency spectrum: Bandwidth of 2W is required the signal. Two sidebands (upper and lower). Example: Consider modulation by the signal on a 1000 hertz carrier: ) 40 cos( 2 ) 20 sin( ) ( t t t m + = and ) 2000 cos( ) ( ) ( t t m t u = Time domain representations: Fourier transform of the message: Fourier transform of the modulated signal showing upper and lower sidebands:...
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This note was uploaded on 11/01/2009 for the course EEE 455 taught by Professor Hui during the Spring '09 term at ASU.
- Spring '09