AN OVERSAMPLING DELTA-SIGMA FREQUENCY-DISCRIMINATOR

A circuit technique for performing oversampled A/D conversion on the p hase/frequency information of an angle modulated signal is presented. It is shown that the technique is equivalent to a classic delta-sigma data conversion with instantaneous frequency as the input variable. De tails of first and second-order implementations of the technique are p resented, and suitability of the technique is discussed for applicatio ns such as in the rapidly evolving personal communications field. The most immediate application will be at the IF stage of a receiver where the discriminator input signal is bandlimited by the IF filter, and w here sufficient amplification has occurred to provide the input signal levels required by the discriminator.