©2008 The McGraw-Hill Companies, Inc. All rights reserved. Electronics Principles & Applications...
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©2008 The McGraw-Hill Companies, Inc. All rights reserved. Electronics Electronics Principles & Applications Principles & Applications Seventh Edition Seventh Edition DSP Audio Examples (Ch. 16 supplement) Charles A. Schuler
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Transcript of ©2008 The McGraw-Hill Companies, Inc. All rights reserved. Electronics Principles & Applications...
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
ElectronicsElectronics
Principles & ApplicationsPrinciples & ApplicationsSeventh EditionSeventh Edition
DSP Audio Examples(Ch. 16 supplement)
Charles A. Schuler
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
The audio examples in this presentation were preparedusing the GoldWave digital audio editor version 4.26.
(www.goldwave.com)
Click this icon to verifythat your sound works.
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
Square wave before filtering
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
Square wave after low-pass filter
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
The GoldWave Device Controls panel
Spectrum(1 kHz square wave)
Spectrum(1 kHz sine wave)
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
HPF(2.7 kHz)
LPF(500 Hz)
400 HzSquarewave
Filtered wave(sine)
Audio example (square wave and filters)
Click the speaker icons to hear the sounds.
The low-pass filter attenuates all harmonicshigher than the 1st (the fundamental).
Filtered wave
The high-pass filter passes the 7th harmonicand all those above.
BPF(2.0 kHz)
Filtered wave(sine)
The band-pass filter passes the 5th harmonic
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
LPF(2 kHz)
Voice Filtered Voice
Audio example (voice and low-pass filter)
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
HPF(500 Hz)
Voice Filtered Voice
Audio example (voice and high-pass filter)
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
BPF0.5 - 2kHz
Voice Filtered Voice
Audio example (voice and band-pass filter)
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
Voice Voice with echo
Audio example (echo effect)
An echo effect is created by addingdelayed samples to the original signal.
Delay Delay
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
ReverseVoice Reversed Voice
Audio example (voice and reverse effect)
The reverse effect flips the end ofthe sampled signal with the beginning
(thus it plays backwards).
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
Voice
Noise
Voice + Noise
Audio example (voice + noise)
LPF(2 kHz)
The noise is broad band and a LPF only helps a little.
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
The importance of signal-to-noise ratio
Very poor
Very good
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
Voice
Clicks
Voice + Clicks
Audio example (voice + clicks)
ClickDSP
The removal of clicks with DSP works very well.
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
BSF(1 kHz)
Voice
1 kHz sine
Voice + 1 kHz sine
Audio example (voice + 1 kHz sine)
The removal of an interfering tone with a band-stopfilter works very well but there is some ringing.
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
Pitchhigher
Voice Altered Voice
Audio example (voice and special effects)
Pitchlower Altered Voice
The pitch is changed by clocking the datato the D/A converter at a faster or slower rate.
©2008 The McGraw-Hill Companies, Inc. All rights reserved.
SE #1400 Hz
square wave
Audio example (400 Hz square wave and special effects)
SE #2
SE #3
SE #4
If you can imagine it, DSP can probably do it!
