| 摘要 |
PURPOSE:To obtain an automatic switching voice detector circuit in a multi system CTV by providing a voice frequency converter, a voice carrier detector and a voice detector circuit frequency switching circuit. CONSTITUTION:When a voice carrier is 5.5MHz, 6.5MHz, 6MHz is outputted by beat component of 0.5MHz, and in case of 6MHz, 6MHz is outputted. This is inputted to a discriminating circuit 6, and H is outputted when 6MHz is inputted, and L is outputted in other cases. SW7 and an FM detector 5 are switched to 4.5MHz and 6.0MHz by the output. That is, when input is 4.5MHz, SW7 is switched to L side, and 4.5MHz goes to the center frequency of the detector 5, and FM detection output is obtained. In the case where input is other than 4.5MHz, SW7 goes to 6MHz side, and 6MHz goes to the center frequency of the detector 5, and FM detection output is obtained similarly.
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