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ANALOG-TO-DIGITAL
CONVERSION

The Pulse Code Modulation (PCM) Technique

By Dr. Ernest Simo


1.0 Nyquist Sampling
Analog to Digital Conversion





An Analog to Digital Converter transforms an analog signal to a digital signal. This process has three steps:
  • Sampling: makes the signal discrete in time.
  • Quantization: makes the signal discrete in amplitude.
  • Source Encoding: represents the quantized levels as a sequence of digital bits.
Sampling does not introduce distortion if the analog input signal is bandlimited and the sample rate is sufficiently high.

Quantization does introduce distortion, and in many cases, contributes as a limiting factor in the quality of the overall system.



ANALOG-TO-DIGITAL CONVERSION
The Pulse Code Modulation (PCM) Technique
© 1999 DR. ERNEST SIMO - SPACE2000
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