| 摘要 |
PURPOSE:To output a synchronizing signal having the same polarity irrespective of the polarity of a synchronizing signal being input, by discriminating the polarity of a synchronizing signal which is input, outputting it as it is in case of the polarity required, and outputting if after reversing its polarity by a polarity reversing circuit in case when the polarity is opposite. CONSTITUTION:A synchronizing signal from the input terminal 1a is provided to the waveform shaping circuit 1, the synchronizing signal which has been waveform- shaped by the circuit 1 is provided to the polarity inverting circuit 2 for inverting the polarity, and also it is input to the first voltage generating circuit 3 for generating the voltage according to the output of the circuit 1. The outputs of these respective circuits 2, 3 are provided to the first and second switching means of the pulse switching circuit 4. And, the transistors TR43, 53 and 56 which constitute the first and second switching means are made conducting or nonconducting by the polarity of the synchronizing signal of the input terminal 1a, the polarity of the synchronizing signal is discriminated, and when the input has the negative polarity, the TR56 is made conducting, the output of the circuit 3a is output from the output terminal 1b, and when it has the positive polarity, a signal having the negative polarity which has been inverted by the circuit 2 is output. |
