An A/D Converter with 10 Bits/Sample by 20 MHz Sampling Rate

An A/D converter circuit system with a very high bit-rate has been developed. It is a series-parallel type, and the input of the last A/D stage is equivalently ac-coupled. This can be allowed by the statistical charactertstics of input signals. A prototype of this A/D converter has the following characteristics: 1) dc coupled analog input-able to accept almost all analog signals as well as television signals; 2) sampling frequency up to 20 MHz; 3) linear coding scheme with 10 bits per sample; 4) linearity error of less than one third of quantizing level; 5) differential gain and differential phase of 0.4% and 0.25°, respectively; and 6) operating temperature range of from 0° to 50°C.