Performance of a Conventional Costas Loop having a Phase Imbalance between In-phase and Quadrature Arms

Abstract

The present paper examines the effect of having a quadrature arm signal with relative phase—(90+α)° to the in-phase arm signal in a Costas loop. Here the additional phase shift a, is a nonzero, positive or negative quantity, arising due to the imperfect design of the phase shifter used in the practical system. First, the tracking response of such a non-ideal Costas loop is examined for a noise-free input. Next its acquisition behavior is studied in the delayed case. Lastly, performance of the loop is examined in the face of noisy inputs.

Indexing terms:

• Costas loop
• 90° phase shifter
• False-locking squaring loss parameter

Additional information

Notes on contributors

R Hati

R Hati was born on 16 February, 1967. She received both her BSc (Hons) and MSc degrees in Physics from the University of Burdwan in 1989 and 1992 respectively. She joined the Department of Physics, Burdwan University, as a research fellow in January, 1995 and is presently working on non-linear dynamical problems related to coherent receivers.

B C Sarkar

B C Sarkar was born in February 1954, in India. He obtained his BSc (Hons), MSc and PhD degrees in Physics, all from University of Burdwan, in the years 1973, 1975 and 1985 respectively. He joined the Post-graduate Faculty of Physics, Burdwan University, in the year 1980 as a lecturer and subsequently became a reader in the same Department in the year 1987. Along with his teaching assignments, Dr Sarkar is actively engaged in research in the field of Synchronous Communication Systems, Non-linear Oscillations, Digital Signal Processing etc. He is supervising research work of his students for their PhD degrees. He has acted as a reviewer of the technical papers submitted to the transactions of IEEE (USA), IEE (UK), IJE (UK). He has published more than 50 papers in different inland and foreign journals and contributed to different national and international symposia.