| 摘要 |
PURPOSE:To detect an interference wave level even if it is larger than a desired wave by utilizing it that a frequency difference in interleave channel interference wave and desired wave is sufficiently larger than the maximum frequency shift of a signal. CONSTITUTION:A level deciding circuit 25 decides whether or not an output of a frequency detector 23 is the maximum frequency shift of a signal or a value or over decided with some margins. A demodulation signal at the frequency region is over a prescribed value only when the level of the interleave channel interference wave exceeds a desired wave level. In giving the average number of times where the desired wave versus interference wave are inverted, the average value of the inverted duration time and the average value of the desired wave versus interference wave ratio as the inverted time rate to the desired wave and interference wave subjected to Rayleigh fluctuation, the inverted time rate is decided definitely. Thus, the mean value of the desired wave versus interleave channel interference wave ratio of an input signal, that is, the quantity of interference is obtained. |
