| 摘要 |
PURPOSE:To generate various confirming sounds, by frequency-dividing an output of a frequency-divider at prestage to an audible frequency signal, turning on the frequency-divider for a prescribed period when a channel changeover switch is operated and introducing the output of the frequency-divider from a speaker. CONSTITUTION:An audible frequency generating circuit 8 is provided in place of an astable multivibrator in comparison with conventional channel selectors. This circuit 8 consists of a frequency-divider 81 and a 2-input AND gate 82. An output terminal of a prestage frequency-divider 22 of a PLL 2 is connected to an input terminal of the frequency divider 81. The output terminal of the frequency-divider 81 is connected to one input terminal of the AND gate 82. To another input terminal of the AND gate 82, an output terminal of monostable multivibrator 4 gated with a reset pulse at the application of channel changeover switches 111-116 is connected. As a result, the confirming tone different in tone scale is obtained for each channel with simple constitution and the articulation at confirmation can be improved. |
