Limitations
There are potential sources of impairment implicit in any PCM system:
- Choosing a discrete value that is near but not exactly at the analog signal level for each sample leads to quantization error.
- Between samples no measurement of the signal is made; the sampling theorem guarantees non-ambiguous representation and recovery of the signal only if it has no energy at frequency fs/2 or higher (one half the sampling frequency, known as the Nyquist frequency); higher frequencies will generally not be correctly represented or recovered.
- As samples are dependent on time, an accurate clock is required for accurate reproduction. If either the encoding or decoding clock is not stable, its frequency drift will directly affect the output quality of the device.
Read more about this topic: Pulse-code Modulation
Famous quotes containing the word limitations:
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—Raymond Chandler (1888–1959)
“The only rules comedy can tolerate are those of taste, and the only limitations those of libel.”
—James Thurber (1894–1961)
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—Lawrence Balter (20th century)