Patent US 4,926,482

High speed computing apparatus for performing real time data compression of analog voice data or digital data to be transmitted over a data link. The incoming data stream is divided into blocks of digital data and the blocks are subdivided into digital samples or elements to be compressed. Each sample is analyzed individually to determine its estimated variance and the marginal return to be gained by alloting the sample one or more of the bits to be employed to define the block of digital data. The bits are assigned samples having the highest estimated variance factor so that an optimum allocation of bits to individual samples is achieved with variable ratio data compression. The allocated bits are employed to encode the samples during real time data compression and transmission.