ece4305_L09

Ece4305_L09 - QPSK M-PSK M-PAM and M-QAM Modulation ECE4305 Software-Defined Radio Systems and Analysis Professor Alexander M Wyglinski Department

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Unformatted text preview: QPSK, M-PSK, M-PAM, and M-QAM Modulation ECE4305: Software-Defined Radio Systems and Analysis Professor Alexander M. Wyglinski Department of Electrical and Computer Engineering Worcester Polytechnic Institute Lecture 9 Professor Alexander M. Wyglinski ECE4305: Software-Defined Radio Systems and Analysis QPSK, M-PSK, M-PAM, and M-QAM Modulation Quadrature Phase Shift Keying M-ary Phase Shift Keying M-ary Pulse Amplitude Modulation M-ary Quadrature Amplitude Modulation Power Efficiency Summary Modulation Format Figure: QPSK Signal Constellation. I So far we have seen modulation schemes that consist of just one of two waveforms I We will now expand our signal constellation repertoire to four distinct waveforms per modulation scheme I In QPSK modulation, a signal waveform possesses the following representation: s i ( t ) = ± A · cos( ω c t + θ ) ± A · sin( ω c t + θ ) (1) Professor Alexander M. Wyglinski ECE4305: Software-Defined Radio Systems and Analysis QPSK, M-PSK, M-PAM, and M-QAM Modulation Quadrature Phase Shift Keying M-ary Phase Shift Keying M-ary Pulse Amplitude Modulation M-ary Quadrature Amplitude Modulation Power Efficiency Summary Computing ε p , QPSK I Solving for d 2 min , we obtain: d 2 min = T Z Δ s 2 ( t ) dt = 2 A 2 T (2) I To find ¯ E b , we need to average over all the signals, which is equal to: ¯ E b = ( E s 1 + E s 2 + E s 3 + E s 4 ) / 4 log 2 ( M ) = A 2 T 2 (3) since E s 1 = E s 2 = E s 3 = E s 4 = A 2 T I Solving for the power efficiency, we get: ε p , QPSK = d 2 min ¯ E b = 4 (4) Professor Alexander M. Wyglinski ECE4305: Software-Defined Radio Systems and Analysis QPSK, M-PSK, M-PAM, and M-QAM Modulation Quadrature Phase Shift Keying M-ary Phase Shift Keying M-ary Pulse Amplitude Modulation M-ary Quadrature Amplitude Modulation Power Efficiency Summary...
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This note was uploaded on 01/13/2011 for the course ECE 4305 taught by Professor Wy during the Spring '10 term at WPI.

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Ece4305_L09 - QPSK M-PSK M-PAM and M-QAM Modulation ECE4305 Software-Defined Radio Systems and Analysis Professor Alexander M Wyglinski Department

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