Communications system having quantiser coder - with code words from word pool assigned to quantisation levels depending on input signal

摘要

The communications system quantises the difference dX between input signal XE and a predicted input sinal X' using a quantiser/coder. The quantised difference is digitally coded, transmitted and decoded at the receiver and the original signal reconstructed. The quantiser/coder has a code word pool of m words and is controlled by the input sinal XE, or by a variable X" dependent on the input signal, such that at least one of the words is assigned one or more quantisation levels depending on XE or X". The number n of the total possible quantisation levels is greater than m. The receiver's decoder converts the receivd words in the quantisation levels associated with these words.