ece4305_L21

ece4305_L21 - Cyclostationary Detection ECE4305...

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Cyclostationary Detection ECE4305: Software-Deﬁned Radio Systems and Analysis Professor Alexander M. Wyglinski Department of Electrical and Computer Engineering Worcester Polytechnic Institute Lecture 21 Professor Alexander M. Wyglinski ECE4305: Software-Deﬁned Radio Systems and Analysis

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Cyclostationary Detection Introduction Mathematical Formulation Sample Spectral Correlation Functions Signal Classiﬁcation Knowledge of Signal Structures I Often we know some of the details behind the signal structure of an intercepted transmission I Data rates I Modulation scheme I Carrier frequency I Guard band locations I Digitally modulated signals possess periodic features that may be implicit or explicit I Carrier frequencies and symbol rates can be obtained using square-law devices I Cyclic extensions can reveal periodic nature of signal structure Professor Alexander M. Wyglinski ECE4305: Software-Deﬁned Radio Systems and Analysis
Cyclostationary Detection Introduction Mathematical Formulation Sample Spectral Correlation Functions Signal Classiﬁcation Deﬁnition of Cyclostationary Processes I A cyclostationary signal is a signal whose statistics vary periodically with time I A signal x ( t ) is wide-sense cyclostationary if its mean and autocorrelation are periodic: R x ( t , τ ) = R x ( t + T 0 , τ ) , t , τ and μ x ( t ) = μ x ( t + T 0 ) I We can express the periodic signal as a Fourier series: R x ± t - τ 2 , t + τ 2 ² = X α R α x ( τ ) e - j 2 πα t (1) where the cyclic frequency α is equal to α = m / T 0 I The Fourier series is the decomposition of a signal into a summation of contributing frequencies Professor Alexander M. Wyglinski ECE4305: Software-Deﬁned Radio Systems and Analysis

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Cyclostationary Detection Introduction Mathematical Formulation Sample Spectral Correlation Functions Signal Classiﬁcation Spectral Correlation Function Implementation I The cyclic autocorrelation function
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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_L21 - Cyclostationary Detection ECE4305...

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