Design of High Speed Analog-tかDigitalConverters

In order toalleviate the effect of the settling time of an operational amplifier used in a serial A-D converter， the following two methods are proposed : 1. The m most significant bits are obtained by a parallel converter， the remaining bits being obtained by a serial converter. 2. The m most significant bits are obtaned by direct use of a high speed comparator instead of the operational amplifier. Conversion errors incurred due to the poor gain of the comparator are corrected for during the succeeding conversion process using the operational amplifier