| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve same code continuity resistance, reduction of response time, and suppression of residual offset voltage, at the same time. <P>SOLUTION: For a burst head, a feed-forward offset compensation circuit instantaneously compensates for offset, and a feed-back type offset compensation circuit then compensates for long time offset variation incurred in the feed-forward offset compensation circuit. When compensating for offset in the burst head by means of the feed-forward offset compensation circuit, an analog switch 41 is turned off and an analog switch 42 is turned on in the feed-back offset compensation circuit, and a low-pass filter 22 whose time constant is small is speedily charged to the required voltage. In timing when speedy charging to a capacitor of the offset compensation circuit is completed thereafter, the analog switch 41 is turned on to input an output voltage of the low-pass filter 22 to a differential amplifier 13, and a low-pass filter 21 whose time constant is great is added to a feedback loop. <P>COPYRIGHT: (C)2010,JPO&INPIT |
