摘要 |
In response to changes in an input binary digital signal, a 3rd order cosine pulse waveform, which, when it is changed in the increasing direction, has "0" level in a first period of T/12 (T corresponding to one-half cycle of the binary digital signal), is changed as a waveform of (h/2)(1+cos(3pit/T)+pi/4) in the next period of 4T/12 (-5T/12<=t<=-T/12) and has an h (constant) level in the remaining period of T/12, and when it is changed in the reducing direction, has the h level in the first period of T/12, is changed as a waveform of (h/2)(1+cos(3pit/T)-pi/4) in the next period of 4T/12 (T/12<=t<=5T/12) and also has "0" level in the remaining period of T/12. By using this pulse wave, a flat part is generated in a time width of T/12 with respect to a judgment point. It is thus possible to improve the immunity to the effects of digital signal jitter, obtain change judgment with a sole single pulse and reduce the circuit scale and the power consumption.
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