JPS5545236A - Multiplex broadcast receiving unit - Google Patents

Abstract

PURPOSE: To make it possible to receive multiple signals stably for a weak electric field and temperature change by providing a timing generation means, which generates sampling pulses throughout a prescribed horizontal scanning time, and controlling a multiple signal sampling means.

CONSTITUTION: TV video signals from terminal 9 are applied to synchronizing signal generation circuit 1 to generate horizontal synchronizing signal HD, vertical synchronizing signal VD and sub-carrier SC and are outputted to clock generation circuit 2 and display timing generation circuit 3. In circuit 3, horizontal synchronizing signals are counted to generate pulse b which becomes H-level in the period from the (n-α)th horizontal scanning time to the (n+α)th horizontal scanning time, and clocks from circuit 2 are counted to apply signal d, which is gated by signal c which becomes H-level during the multiple information existence period, to multiple signal sampling circuit 4, thereby sampling multiple signals. Since this sampling period is wider than the multiple signal existence horizontal scanning time, errors of multiple signal sampling are small even for a weak electric field. Signals from circuit 4 are converted to parallel signals and are outputted through code signal detection circuit 6 and gate circuit 8.

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