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I need help with telecommunications homework problem?
It is necessary to transmit the human voice using a frequency range from 300 Hz to 3.5 kHz using a digital system.
(a) What is the minimum required sampling rate, according to theory?
(b) Why would a practical system need a higher rate than the one you calculated in part (a)?
2 Answers
- RickLv 78 years agoFavourite answer
a) 7 kHz
b) 7 kHz is the theoretical minimum, but that would only give you two sample points at 3.5 kHz, so the resoulting waveform would be very badly distorted. Even with 10 samples per cycle it would have quite a bit of distortion. This is why digital audio uses something like 44 kHz minimum.
- ChuckLv 68 years ago
Before sampling you must band-limit the input signal to avoid producing artifacts from frequency components above 2x Fmax. Since filters are not perfect you would need to set the low pass filter to roll off around 3.5 KHz and set the sample rate higher than 2 x 3.5 KHz to avoid producing in-band artifacts. 8 KHz is a typical sample rate for telephony.
Source(s): MSEE
