Modulating/demodulating circuit for multiplex recording/playback of data in a magnetic recording/playback system
AssigneeFuji Photo Film Co., Ltd.
InventorsYoshiki Iwase, Katsuo Nakadai, Izumi Miyake, Kiyotaka Kaneko, Kazuya Oda
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Abstract
A data signal is modulated by an exclusive-OR operation applied to a carrier signal and a data signal to be recorded. Demodulation is similarly performed by an exclusive-OR operation applied to the carrier signal and signal indicative of read data. This makes it possible to construct the modulating/demodulating circuit in the form of a digital circuit.
Claims6
A modulating/demodulating circuit for multiplexed recording/playback of data and a video signal having a horizontal synchronizing signal to/from a magnetic storage medium in a magnetic recording/playback system, comprising:
- carrier signal generating means for generating a carrier signal for multiplexed recording/playback of data, and
- an exclusive-OR circuit, receiving a signal representing data to be recorded on the magnetic storage medium, or a data signal read from a magnetic storage medium and said carrier signal,
- said carrier signal generating means including,
- a counter for counting a high frequency clock signal to produce said carrier signal,
- and counter reset means, synchronized to said horizontal synchronizing signal, for generating a reset signal applied to said counter to reset the count produced thereby, said carrier signal produced by said counter being thereby synchronized to said horizontal synchronizing signal.
Dependencies are inferred from the claim text.