CHANNEL SELECTION POSITION DETECTOR

摘要

PURPOSE:To realize selection for the channel selection position at the end of selection in a simple method by counting the number of the external pulses required to reach the channel selection position with the channel selection position used as the reference position. CONSTITUTION:The voltage of the channel selection position of channel selection switches SW1-SW12 is applied to position-up pulse generator circuit 36. And the free-running clock signal of circuit 36 is selected, and the output Q is applied to control circuit 22 of selection integrated circuit 20 as well as to position-up-counter 37 for counting the pulse row. The count number of circuit 37 is memorized in memory part 38, and furthermore gate circuit 40 is controlled by the count value. And the output of circuit 40 is applied to position-down pulse generator circuit 39, and the channel selection position at the end of selection and sent from circuit 39 is applied to circuit 22 to control electronic switches S1-S12 and then to operate tuner 1.