| 摘要 |
PURPOSE:To attain quick and accurate transmission for data code with simple and inexpensive constitution by applying PLL detection to a received FSK modulation signal to form an FSK demodulation signal, forming an input presence detecting signal during the input period of the FSK modulation signal and decoding and forming the received data code. CONSTITUTION:A demodulation section 13 consists of an integrated circuit 13b forming an input presence detecting means of an FSK modulation signal together with a PLL detection means and an AND gate 13g gate 13g decoding and forming the control code through the logical combination between the FSK demodulation signal formed by the detection of the PLL detection means and the input presence detecting signal of the input presence detecting means. Thus, even is the PLL detecting means executed mis-detection even with a weak FSK modulation signal received, if the input presence detection signal of the input presence detecting means is not outputted, the control code is not decoded and the control code is decoded accurately. Then the received FSK modulation signal is demodulated quickly and the received control code is decoded accurately, the quick and accurate control is applied based on the control code and the constitution is simplified with low cost by omitting the lockup time. |
