| 摘要 |
PURPOSE:To attain control identification to an equalized waveform by providing a sampling pulse before and after the central point of time of a eye pattern, supervising the aperture of the eye before and after the central point of time and correcting it automatically if the self-timing is deviated from the central point of time of the eye pattern. CONSTITUTION:The aperture of the eye calculated by eye aperture detection circuits 19, 20 by using sampling signals A, C is inputted to inputs A, B of a comparator 17. When A>B, the output of the comparator 17 goes to a high level and in other cases, the output goes to a low level. When A>B, the output of a counter 118 is decremented by 1 by an input clock from a shift register 16, and when A<B conversely, the output is incremented by 1. Thus, sampling signals, A, B, C are lefted to the right/left by the comparison of the eye aperture calculated by the eye aperture detection circuits 19, 20. Thus, the sampling signal B is sampled at the center of the eye pattern of an output signal of full wave rectifier circuit 2 at S/H circuit 10. |
