| 摘要 |
PURPOSE:To search frequencies in a short time by controlling optionally the continuous changing speed of the receiving frequency of a tuner. CONSTITUTION:A control key 30 gives instructions to a step counter 31 and a pulse width modulation data output circuit 28. The counter 31 counts continuously the clock signals sent from a clock selecting circuit 33 while the key 30 is pushed and changes the pulse width demodulation output data when the counter 31 has an overflow to change the output of a pulse width modulation circuit 27. The clock signals counted by the counter 31 are equal to the output of a reference oscillator 29 or the output obtained by dividing the output of the oscillator 29 by a divider 32. This output is selected by a clock selecting circuit 33 with the output of a holding circuit 36. The circuit 36 holds the deciding output given from a signal deciding circuit 25 or releases said holding state by a control circuit 35.
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