A novel A/D converter utilizing phase modulation

This paper describes a novel A/D conversion architecture suitable for high-speed operation. The basic idea is to convert the amplitude of an analog input into the phase rotation of a carrier signal, comparing the rotation angle to that of the carrier. At that point, by weighing the phase conversion range in a binary manner, the digital code corresponding to the analog input can be obtained. An A/D converter utilizing the concept above has been built out of components on the market. Its resolution is four bits and the carrier frequency is 870 MHz. It successfully converts an input signal into 14 steps of digital code. Also the converter operates up to 80 MHz, which is close to the theoretical limit of 108 MHz