| 摘要 |
PURPOSE:To improve the shortening and equalizing accuracy of a leadingin time even when a system with a low bit rate is used by allowing an artificial BET detecting circuit or the like to artificially detect the quantity of waveform distortion generated by fading, and even if fading is generated and errors are increased, switching an integration time constant in each case. CONSTITUTION:The inverted input side of an operation amplifier 218 is connected to the input terminal 211 of an integrating circuit 104 through an input resistor 212. A parallel circuit consisting of an amplifying resistor 217 and integrating capacitors 213, 216 is connected between the inverted side input terminal and output terminal of an operational amplifier 218, a switch 215 is connected to an integrating capacitor 213 in series, and an integration time constant is switched by turning on/off the switch 215. The integration time constant of the integrating circuit is set up so as to sufficiently maintain the accuracy even in a low bit rate normally as a long time constant, and when the influence of fading starts to appear, the time constant is switched to a short integration time constant. Consequently, highly accurately equalization can be attained even in the case of a low bit rate and the equalizer can sufficiently follow up also the changing speed of fading. |
