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Sampling frequency

Signals must be filtered prior to sampling. Theortically the maximum frequency that can be represented is half the sampling frequency. In practice a higher sample rate is used to allow for non-ideal filters.

The signal is now represented at multiples of the sampling period, T, as s(nT) which is also written tex2html_wrap_inline2787.

Telephone speech is sampled at 8 kHz. 16 kHz is generally regarded as sufficient for speech recognition and synthesis. The audio standard is a sample rate of 44.1 kHz (Compact Disc) or 48 kHz (Digital Audio Tape) to represent frequencies up to 20 kHz.

Speech Vision Robotics group/Tony Robinson