Förfarande för åstadkommande av ett syntesfilter för långtidsintervall samt syntesfilter för talkodrar

摘要

The description pertains to a synthesis filter, which models the effect of the fundamental frequency of speech, for digital speech coders operating on the analysis-by-synthesis principle. By means of the invention it is possible also to model such high fundamental frequencies as have a shorter corresponding cycle length than the frame length employed in the analysis-by-synthesis method. The filter construction according to the invention furthermore involves the use of a number of parallel separately adaptable synthesis memory blocks. This permits the use as an excitation signals that have been stored in memory several frames earlier.