A Novel High Speed A/D Conversion Technique using a Voltage Controlled Oscillator and a Microwave Digital Discriminator

A very high speed A/D conversion teahnique potentially suitable for video and radar applications is described [1]. The new teahnique combines two existing microwave components, a voltage-controlled oscillator and a digital frequency discriminator. The digital discriminator output gives parallel bits directly in Gray code form, eliminating the costly and complex encoding logic circuits of conventional fast AID conversion techniques. Only n comparators are required for an n-bit word and the basic advantage of the teahnique is that the complex logic operations of the parallel (or flash) baseband approaah are eliminated. Experimental performance of a 4-bit A/D converter using the new teahnique at a low frequency is given confirming the validity of the principle.