Time delay digital tanlock loop with linearized phase detector

Abstract

This paper presents a time delay digital tanlock loop with a linearized phase detector (TDTL-LPD) architecture. This is achieved through replacement of the time delay unit of the TDTL by a variable delay whose phase error is controlled by a feedback mechanism driven by the output of the inverse tan phase detector. The change in this output is proportional to the changes in the input signal frequency of the system. This results in keeping the quadrature relationship between the two channels that make up the TDTL. This linearization of the phase error detector results in the improvement of the system performance when used in communication system applications such as FSK (frequency shift keying) demodulation.