Abstract: A method and apparatus for providing mass storage of vocal information by means of a digital communication system for use with a training simulator is disclosed. Unlike prior art analog records and playback systems, such as tapes, etc., the inherent advantages and flexibility available with respect to a digital system including randomly accessible voice messages, convenience of editing the stored data, and management and control by the computational system of the training simulator are available with the present invention. In general, the system of this invention comprises an input device, such as a microphone (30), an encoder (54) for encoding the analog information from the microphone (32) to digital format, a digital processing controller or computer (20) for processing the digital communication data in response to a stored program such that it is suitable for use with the computational system, and a mass storage media (38) for storing the processed digital data.

Abstract: A data compression apparatus is described having an encoder and a decoder. Data in the form of an N-bit data message from an external data source is received in the encoder and stored in an N-bit memory. Coupled to the memory is a "one's" detector and three arithmetic units. The "one's" detector counts the number of logical "one's" in the N-bit message irrespective of their position in the memory for generating a number Q. The three arithmetic units sum columns of the contents of the memory in three predetermined sequences for generating three numbers A, B and C. The numbers A, B, C and Q are then used to form a P-bit data message, where P is less than N for a sufficiently large N - e.g., for N=256, N/P is approximately 2.8 - for transmission to the decoder. The decoder is provided with an N-bit memory, three arithmetic units and a comparison circuit. Upon receipt of the P-bit data message, Q logical "one's" are stored in the decoder memory.