signal waveform delays differs depending on the condition of the signal transmission channel and the maximum number of the required taps of each of the equalizers 33 and 34 differs also depending on the condition of the signal transmission channel suppose now that the impulse response of the signal transmission channel is for example as shown in fig2 in such a case the waveform components 23 to 26 are delayed by 4t from the main waveform component 22 relative to time and the waveform component 21 is advanced by 1t from the main waveform component 22 relative to time in this case the fir type digital filter having 2 taps and the iir type digital filter having 4 taps can satisfactorily deal with the latter half data part of the burst signal while the fir type digital filter having 5 taps and the iir type digital filter having 1 tap can satisfactorily deal with the former half data part of the burst signal this is because in the case of the equalizer used for equalizing the latter half data part of the burst signal in the order of from the reference signal part to the latter half data part in the direction of the arrow b in fig1 the fir type digital filter which is effective for cancelling the waveform component 21 appearing before the main.