APPARATUS FOR QUANTIZING AN INPUT GROUP OF DATA SAMPLES INTO ONE OF N QUANTIZED GROUPS OF DATA VIA A PROCESS ON LESS THAN N/2 REFERENCE GROUPS OF DATA SAMPLES

A quantizer, which converts an input group of data samples into one of N quantized groups of data samples, does so by performing several dot products and compares. Each dot product is between the input group of data samples and a reference group of data samples u.sub.x, and each compare is with the dot product result and a constant k.sub.y. All of the reference groups of data samples and all of the constants are stored in a memory. This memory holds only N-1 constants and less then N/2 reference groups of data samples. A memory saving of several thousand percent is achieved by limiting the memory to hold no more then 2r reference groups of data samples where r is the number of samples in the input group, or no more then 2 log.sub.2 N reference groups of data samples.