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Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1
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Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Dec 21, 2015

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Page 1: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Discrete-Time Fourier Methods

M. J. Roberts - All Rights Reserved. Edited

by Dr. Robert Akl

1

Page 2: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Discrete-Time Fourier Series Concept

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

2

Page 3: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

3

Discrete-Time Fourier Series Concept

Page 4: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

4

Discrete-Time Fourier Series Concept

Page 5: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

5

Discrete-Time Fourier Series Concept

Page 6: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

6

Discrete-Time Fourier Series Concept

Page 7: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Discrete-Time Fourier Series Concept

Page 8: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Discrete-Time Fourier Series Concept

Page 9: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Discrete-Time Fourier Series Concept

Page 10: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Discrete-Time Fourier Series Concept

Page 11: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Discrete-Time Fourier Series

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 12: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Discrete Fourier Transform

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 13: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Discrete Fourier Transform

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 14: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Discrete Fourier Transform

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 15: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DFT Example

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 16: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 17: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 18: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 19: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 20: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 21: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 22: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 23: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 24: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 25: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The DFT Harmonic Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 26: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Convergence of the DFT

• The DFT converges exactly with a finite number of terms. It does not have a “Gibbs phenomenon” in the same sense that the CTFS does

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 27: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Discrete Fourier Transform

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 28: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DFT Properties

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 29: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DFT Properties

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 30: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DFT Properties

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 31: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Dirichlet Function

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 32: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DFT Pairs

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 33: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Fast Fourier Transform

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 34: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Fast Fourier Transform

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 35: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Generalizing the DFT for Aperiodic Signals

Pulse Train

This periodic rectangular-wave signal is analogous to thecontinuous-time periodic rectangular-wave signal used toillustrate the transition from the CTFS to the CTFT.

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 36: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DFT of Pulse Train

As the period of the rectangular wave increases, the period of the DFT increases

Generalizing the DFT for Aperiodic Signals

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 37: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

NormalizedDFT of

Pulse Train

Generalizing the DFT for Aperiodic Signals

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 38: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The normalized DFT approaches this limit as theperiod approaches infinity.

Generalizing the DFT for Aperiodic Signals

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 39: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Definition of the Discrete-Time Fourier

Transform (DTFT)

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 40: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Discrete-Time Fourier Transform

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 41: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Pairs

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 42: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Generalized DTFT

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 43: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Generalized DTFT

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 44: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Generalized DTFT

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 45: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Forward DTFT Example

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Page 46: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Forward DTFT Example

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 47: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Forward DTFT Example

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Page 48: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

More DTFT Pairs

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Page 49: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Properties

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Page 50: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Properties

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Page 51: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Properties

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 52: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Properties

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 53: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Properties

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Page 54: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Properties

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Page 55: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Properties

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 56: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Properties

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 57: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

DTFT Properties

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 58: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 59: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 60: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 61: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 62: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 63: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

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Page 64: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

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Page 65: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl

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Page 66: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

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Page 67: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Transform Method Comparisons

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Page 68: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

The Four Fourier Methods

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Page 69: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Relations Among Fourier Methods

Multiplication-Convolution Duality

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Page 70: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Relations Among Fourier Methods

Parseval’s Theorem

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Page 71: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Relations Among Fourier Methods

Time and Frequency Shifting

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Page 72: Discrete-Time Fourier Methods M. J. Roberts - All Rights Reserved. Edited by Dr. Robert Akl 1.

Relations Among Fourier Methods

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