Automatic channel selection apparatus

DETAILED DESCRIPTION What is claimed is 1.
An automatic channel selection apparatus comprising: an electronic tuner having a local oscillator an oscillation frequency of which is controlled in accordance with an applied voltage; a voltage sweep circuit for sweeping the voltage to be applied to said local oscillator; means for deriving from an output of said local oscillator, signals of different phases and combining said signals; a detector for envelope-detecting an output of said meas; and means for counting the number of the output signals of said detector which changes periodically each time the oscillation frequency of said local oscillator changes by a given amount which is inversely proportional to the phase difference between said signals to stop the voltage sweep of said voltage sweep circuit when the count reaches a specified count.
2.
An automatic channel selection apparatus comprising: an electronic tuner having a local oscillator an oscillation frequency of which is controlled in accordance with an applied voltage; a voltage sweep circuit for sweeping the voltage to be applied to said local oscillator; means for deriving from an output of said local oscillator, signals of different phases and combining said signals; a detector for detecting a combined signal from said means to produce a signal which changes at a cycle period which is inversely proportional to the phase difference between said signals; a channel number entry device; a counter for counting up the output of said detector by the number corresponding to a channel number entered by said channel number entry device and producing an end of count signal when the counting operation is completed; and means responsive to said end of count signal from said counter for stopping the voltage sweep of said voltage sweep circuit.
3.
An automatic channel selection apparatus according to claim 2 further comprising a switch connected to apply the output of said detector to an input terminal of said local oscillator and being adapted to be turned on by said end of count signal, whereby said output signal of said detector is supplied to said local oscillator at the time of the completion of the counting operation to carry out automatic frequency control