W. C. Lindsey

Bio: W. C. Lindsey is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 77 citations.

A bibliography of the theory and application of the phase-lock principle

Abstract: A literature search was conducted in an effort to collect and compile as many references on the phase-locked loop as possible. Although not all inclusive, a comprehensive listing of approximately 800 references covering the past two decades of work reported throughout the world are presented. The compilation is given in two parts: first by categories, and then alphabetically by authors.

An Improved Adaptive Power Line Interference Canceller for Electrocardiography

Abstract: Power line interference may severely corrupt a biomedical recording. Notch filters and adaptive cancellers have been suggested to suppress this interference. We propose an improved adaptive canceller for the reduction of the fundamental power line interference component and harmonics in electrocardiogram (ECG) recordings. The method tracks the amplitude, phase, and frequency of all the interference components for power line frequency deviations up to about 4 Hz. A comparison is made between the performance of our method, former adaptive cancellers, and a narrow and a wide notch filter in suppressing the fundamental power line interference component. For this purpose a real ECG signal is corrupted by an artificial power line interference signal. The cleaned signal after applying all methods is compared with the original ECG signal. Our improved adaptive canceller shows a signal-to-power-line-interference ratio for the fundamental component up to 30 dB higher than that produced by the other methods. Moreover, our method is also effective for the suppression of the harmonics of the power line interference

Hold-In, Pull-In, and Lock-In Ranges of PLL Circuits: Rigorous Mathematical Definitions and Limitations of Classical Theory

Abstract: The terms hold-in, pull-in (capture), and lock-in ranges are widely used by engineers for the concepts of frequency deviation ranges within which PLL-based circuits can achieve lock under various additional conditions. Usually only non-strict definitions are given for these concepts in engineering literature. After many years of their usage, F. Gardner in the 2nd edition of his well-known work, Phaselock Techniques, wrote “There is no natural way to define exactly any unique lock-in frequency” and “despite its vague reality, lock-in range is a useful concept.” Recently these observations have led to the following advice given in a handbook on synchronization and communications: “We recommend that you check these definitions carefully before using them.” In this survey an attempt is made to discuss and fill some of the gaps identified between mathematical control theory, the theory of dynamical systems and the engineering practice of phase-locked loops. It is shown that, from a mathematical point of view, in some cases the hold-in and pull-in “ranges” may not be the intervals of values but a union of intervals and thus their widely used definitions require clarification. Rigorous mathematical definitions for the hold-in, pull-in, and lock-in ranges are given. An effective solution for the problem on the unique definition of the lock-in frequency, posed by Gardner, is suggested.

Performance of Phase-Locked Loops in the Presence of Fading Communication Channels

Abstract: An approach is presented for the analysis of phase-locked loops whose input signal has passed through time-varying channels. The specific channels considered in detail are the Rice-Nakagami, Rayleigh, and lognormal fading channels. Loop performance is characterized in terms of the steady-state probability density function of the reduced phase error process. The basic parameters which characterize performance include the loop signal-to-noise ratio (SNR) and the variance and bandwidth of the fading components introduced by the channel. Particular channel models are used to illustrate the theory for the firstorder loop. The results are also applied to the analysis of the PSK noisy reference problem in the presence of these time-varying channels.

Phase synchronizing, a nonrigid, distribution transmit-receive radar antenna array

Abstract: A means is described for self-organizing a nonrigid, distributed, transmit-receive antenna array for use in airborne radar. The techniques are applicable to ground-based or shipborne radar as well. Methods are described for initializing the array using various primary microwave illuninators. The description of phase conjugation techniques and means for distributing phase reference to all elements in the array are the central parts of the paper.