Abstract: A multi-channel digital random access recorder-player receives an analog audio signal, converts the audio signal into a digital signal, and stores the digital signal in a memory for random access. The memory includes sixteen channels, each channel having sixteen memory boards, each channel and each memory board being assigned a unique four bit binary address by an address counter. An external control is provided by which the user selects an address for recording or playback and a comparator compares the selected address with the addresses of the memory. When the memory address corresponding to the selected address is detected, that memory board is enabled so that data can be recorded on the memory board or retrieved from the memory board for playback through an audio output device such as a loudspeaker. The recorder-player thereby provides random access to a memory. Also provided is a system in which several modules, each with a logic board and a memory, are combined into a single system.

Abstract: The invention is a digital record/playback apparatus including an input digital filter, and A/D converter, a solid state memory, a D/A converter and an output digital filter. The entire system is driven off a single clock source which allows the frequent response of the filters to be modified simultaneous with the sampling frequency of the A/D and D/A converter. This allows the record/playback apparatus to record low frequency signals, such as medical data, as well as relatively high frequency signals such as voice, by simply changing the frequency of the clock source. In addition, the apparatus includes an expandable memory which allows recording of up to one hour or more of program material.