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US 5,353,168 AGranted
Recording and reproducing system using time division multiplexing
AssigneeRacal Recorders Limited
InventorNeil M. Crick
Life of this patent
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Abstract
A system for recording analogue and/or digital signals (especially analogue voice signals) on magnetic tape has a plurality of individual input channels and a time division multiplexing circuit which samples the analogue signals in the input channels cyclically, in a pre-arranged sequence. The samples are output to a single output channel for recording on a standard VHS magnetic tape. In the replay mode, recorded signals are distributed to respective output channels by a demultiplexing circuit.
Claims3
A recording and reproducing system comprising,
- a plurality of individual input channels for receiving respective input signals having respective levels;
- time division multiplexing means for sampling the respective input signals cyclically, according to a predetermined sequence of the input channels and for outputting a succession of samples occupying respective time slots, each sample representing a level of an input signal received in a respective input channel during a respective time slot, the samples derived from one of the input channels being used as synchronisation signals;
- frequency modulation means for frequency modulating the succession of samples output by said time division multiplexing means to produce frequency-modulated samples;
- means for recording the frequency-modulated samples, as an analogue signal, on magnetic recording tape;
- means for reading the frequency-modulated samples from the magnetic recording tape;
- frequency demodulation means for demodulating the frequency modulated samples read by the reading means to produce a succession of frequency-demodulated samples,
- a plurality of output channels, each output channel corresponding to a respective input channel;
- time division demultiplexing means for distributing the frequency-demodulated samples output by said frequency-demodulation means to respective output channels;
- and
- synchronisation signal detection means for detecting the frequency-demodulated samples that are used as synchronisation signals, the time division demultiplexing distributing the frequency-demodulated samples output by said frequency demodulation means to respective output channels in accordance with the timing of the detected synchronisation signals.
7 more elements
Dependencies are inferred from the claim text.