| 摘要 |
PURPOSE:To allow the equalization characteristics of a digital signal to meet a pulse mask by cascading a phase linear type low-pass filter to an equalizing circuit. CONSTITUTION:The digital signal of a digital transmitter 5 is converted by an U/B converting circuit 9 into a bipolar signal. This bipolar signal is passed through the phase linear type low-pass filter LPF10 with cutoff characteristics of the pulse frequency f0 of the signal to remove components higher than the frequency f0, equalized preliminarily by a next-stage waveform equalizing circuit 8, and sent out to a cable 6 through a terminal 7. In this case, even when the transmission characteristics of the cable 6 deteriorate at the high frequency side, they are approximated to standard characteristics and the equalized pulse meets the prescribed pulse mask. |
