Saw transition detector for psk signals

Abstract

A phase transition detector for PSK signals which utilizes a dual channel SAW differential delay line to achieve a required delay. Each channel or path of the SAW device comprises an input and an output transducer. The two channels provide a predetermined differential delay (T) inasmuch as they are of different lengths. A PSK input signal is delivered to a power splitter, with the output therefrom coupled to the pair of input transducers of the SAW device. The output transducers are coupled to a multiplier which serves to detect phase transitions in the input PSK signal. The multiplier output is coupled to an output terminal via a low pass filter which provides harmonic repression. In another embodiment a SAW device comprises a bank of dual channel differential delay lines with each dual channel set to a different predetermined delay (T) so that a plurality of PSK signals of different chip rates can be separated out and detected. The PSK input signals are delivered to a power splitter, with the output therefrom coupled to a pair of input transducers of the SAW device. Output transducers are spaced predetermined distances from one or the other of said input transducers. Parallel sets of multipliers and low pass filters are coupled to predetermined SAW output transducers. Each multiplier serves to detect the phase transitions in one, and only one, PSK input signal. The input transducer(s) can be placed near the center of the SAW device, with the output transducers placed on the same, or either, side of the input transducer(s).