PURPOSE: To make it unnecessary for a person in charge of maintenance to adjust a reception-time timer while eliminating the need to use an expensive reception-time timer, by correcting the reception-time timer by use of a time commercial message.
CONSTITUTION: At the time of a commercial message (CM) broadcast delivered from a TV station, a CM discrimination signal and a CM decision signal that indicates the discrimination signal are broadcasted being superposed in audio bands of channels CH1∼CH3. In this CM broadcast, a synchronizing sound generated a certain time after the start of a screen is previously included and channels CH1∼CH3 of this CM broadcast are discriminated by BPF31∼33 of a signal receiving circuit and applied to A/D converters 37∼39 so as to discriminate a CM decision signal by the signal of sampling timer 40, thereby applying the signal to microprocessor 41. Then, the broadcast time and received CM broadsast are compared by processor 41 to the kinds of CM broadcasts previously recorded in memory 8 and on the basis of the comparison result, the time of reception-time timer 9 is adjusted.
SATOU YASUO
SHIRATORI HIDEKAZU
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