| 摘要 |
PURPOSE:To reduce remarkably signal selection processing time by extending a control time when a selection output of a variable filter exists and transiting the control to the succeeding control without extending the control time when the selection output does not exist. CONSTITUTION:As a signal varying the selection central frequency of a variable filter 6, the duration time of signals fc1-fcn is extended from a time T to a time (T+ T) when the selection output of the filter 6 is present, where T is the duration time of the signals fc1-fcn given from a control section 7 to the filter 6. When the selection output of the filter 6 is absent at the time T, the next control signal is scanned. Thus, the presence of signal is decided when the output signal of the filter 6 is durated for a sufficiently long period and since mis-detection by a transient pseudo signal due to noise or the like is prevented, the information reliability of the signal is improved. Since the scanning is applied to the succeeding control signal at the time T in the absence of the selection output, the scanning time is reduced. |
