INTRODUCTION TO DIGITAL SIGNAL PROCESSING

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INTRODUCTION TODIGITAL SIGNAL PROCESSING

• Dr. Hugh Blanton
• ENTC 4347

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TOPICS

1. Impact of DSP
2. Analog vs. digital why, what how
3. Digital system example
4. Sampling aliasing
5. ADCs performance choice
6. Digital data formats

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Digital vs Analog
Digital Signal Processing
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Impact of DSP on Modern Living
Cellular/mobile telephony Speech and channel
coding Voice and data processing Power
management Multipath equaliztion
Digital audio Stereo and surround
sound Audio equalization and mixing
Electronic music
Medical electronics Critical/intensive care
monitors Digital X-rays
ECG analyzers
Cardiac monitors
Medical imaging
Automotive Digital Audio
Digital Radio
Personal communication systems
Active suspension
Personal computer Sound cards
Data storage and retrieval Error
correction/concealment Multimedia
Modems
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Analog digital signals
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DSP aim tools
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Digital system example
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Digital system implementation
KEY DECISION POINTS Analysis bandwidth, Dynamic
range
Pass / stop bands.

• Sampling rate.

No. of bits. Parameters.
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Sampling
How fast must we sample a continuous signal to
preserve its info content?
Why?
Frequency misidentification due to low sampling
frequency.
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Sampling - 2
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The sampling theorem
A signal s(t) with maximum frequency fMAX can be
recovered if sampled at frequency fS gt 2 fMAX .
Theo
Multiple proposers Whittaker(s), Nyquist,
Shannon, Kotelnikov.
Naming gets confusing !
Nyquist frequency (rate) fN 2 fMAX or fMAX or
fS,MIN or fS,MIN/2
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Frequency domain (hints)

• Time frequency two complementary signal
  descriptions. Signals seen as projected onto
  time or frequency domains.

Warning formal description makes use of
negative frequencies !
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Sampling low-pass signals
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Antialiasing filter
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Under-sampling (hints)
Using spectral replications to reduce sampling
frequency fS reqments.
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Over-sampling (hints)