Write a short note on Subband coding.
1 Answer

Subband coding :

  • In subband coding the input signal is first split into numberof non overlapping frequency bands by band pass filters.
  • The output of each band pass filter is decimated or down sampled by a factor M.
  • This can be achieved by retaining every M$^{th}$ sample of the filter output and discarding M-1 samples.
  • The output of decimator is quantized using the technique like PCM, DPCM, etc.and transmitted.
  • At the receiver and inverse sequence of events takes place.
  • The subbands are demultiplezed and decoded and theneach subband signal is interpolated by inserting zeros to replace the samples discarding during decimation at the transmitter.
  • The output of the interpolator is applied to band pass filter.
  • All bandpass filter output are summed together to reproduce the original signal.
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