| 摘要 |
PURPOSE:To obtain an automatic interference wave canceling circuit excellent in interference wave canceling effect even when there is a time zone in which a desired wave becomes off by supplying a signal generated when the first detecting device detects the absence of the desired wave and the second detecting device detects the presence of the interference wave as the second controlling signal of a sampling holder. CONSTITUTION:When a signal that indicates the absence of the desired wave signal and the presence of all interference waves is generated by a signal off detecting device 14, a signal on detecting devices 15-1-15-n and an AND device 16, it is supplied to sampling holders 22 of error detecting controlling circuits 13-1-13-n as a sample signal SMPL. While the sample signal SMPL of the sample holder 22 is in the state of on, the output of a correlation detector 21 is inputted to a low pass filter as it is, and when the sample signal SMPL becomes the state of off, the output voltage of the sample holder 22 at the moment is maintained at constant in sufficiently long period. Detection of on and off state of the signal is made by the envelope detection of each IF signal and the threshold detection of the detection output. |
