| 摘要 |
PURPOSE:To obtain a digital filter completely free from delay by forecasting the succeeding sampled signal almost accurately from the current and past sampled input signals by using the digital filter having a specific transmission function and outputting the forecasted signal. CONSTITUTION:A sampled signal inputted from an input terminal 200 is delayed by delay circuits 201(2)-201(N) every sampling period, multiplied by factors in factor circuits 202(1)-202(N) and then synthesizing respective outputs of the circuits 202(1)-202(N) by an adder 203 to output the added signal from an output terminal 204. The digital filter is provided with a transmission function shown in the formula II when a digital filter having a transmission factor shown in the formula I having the minimum phase transition characteristics having no zero point except a unit circle on the plane (z) has characteristics for suppressing a signal in a prescribed band. Consequently, the succeeding sampled signal can be almost accurately forecasted and outputted from the current and past sampled input signals. Namely, the input signal can be advanced by one sampling period, so that the digital filter completely free from delay can be obtained and the feedback type filter can be formed by a circuit element having a comparatively low operation speed.
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