Results 231 to 240 of about 1,202 (266)

False-Lock Performance Improvement in Costas Loops

IEEE Transactions on Communications, 1982
A technique is described to reduce the probability of false-lock in Costas loops. This is where a frequency offset arises at a multiple of half the incoming data rate due to finite bandwidth of the arm filters. A modification is described to process components of this offset so as to augment the feedback control voltage. The performance is analyzed and
Amir H. Makarios, Timothy C. Tozer
openaire   +1 more source

An Improved Lock Detection Algorithm for Costas Loop

2012 IEEE 14th International Conference on High Performance Computing and Communication & 2012 IEEE 9th International Conference on Embedded Software and Systems, 2012
The Costas loop is the most common carrier synchronization structure in receiver using BPSK modulation. Reliable detection of carrier lock condition is important to the BPSK receiver. In this paper, an improved lock detection algorithm for Costas loop is proposed.
Nan Zhu, Wenquan Feng, Shilong Zhang, Suxiao Liu   +3 more
openaire   +1 more source

False Lock and Bifurcation in Costas Loops

SIAM Journal on Applied Mathematics, 1989
Summary: New results are given on the phenomenon of data-related false lock in a Costas loop that contains a perfect integrator in its loop filter. The input carrier to the loop is assumed to be bi-phase modulated with a \(T'\) periodic binary sequence constructed from Manchester symbols; there are p symbols per period.
openaire   +1 more source

Modified Costas Loop for BPSK

2017
This chapter describes the modified Costas loop for BPSK. While the conventional Costas loop operated with real signals, the modified circuit works with the so-called pre-envelope signal. This is a complex signal, also referred to as “analytical signal.” The real input signal of this Costas loop is converted to the pre-envelope signal using a Hilbert ...
openaire   +1 more source

False lock in Costas loops

[1988] Proceedings. The Twentieth Southeastern Symposium on System Theory, 2003
Results are given on the phenomenon of data-related false lock in a Costas loop which contains a perfect integrator in its loop filter. The input carrier to the loop is assumed to be biphase-modulated with a T' periodic binary sequence constructed from Manchester symbols; there are p symbols per period.
openaire   +1 more source

The design and implementation of Biphase Costas Loop

Journal of the Chinese Institute of Engineers, 1982
Abstract At present, transmitting data or digital message in carrier band via digital modulation such as digital radio has become more and more popular, and the various digital modulation techniques most oftenly employed almost invariably involve changing the carrier phase in some particular way according to the baseband message entering the modulator.
Hen‐Wai Tsao, Lee‐Chuan Chang
openaire   +1 more source

Alias Lock Behavior of Sampled-Data Costas Loops

IEEE Transactions on Communications, 1980
The potential false lock problem associated with the sampled data type of Costas loop implementation is addressed in this paper. The term "alias lock" is used here to differentiate this type of false lock behavior from the data sideband false lock behavior of analog Costas loops [1]-[8].
Marvin K. Simon, Kai T. Woo
openaire   +1 more source

Analysis and Implementation of Modified Costas Loop for QPSK

2015 International Conference on Intelligent Networking and Collaborative Systems, 2015
This paper proposed a new Modified Costas loop to achieve carrier wave synchronization for QPSK with equal prior probability, as the conventional PLL can't make it due to the absence of the carrier partition. Models about phase detector, loop filter, and voltage controlled oscillator are designed in Simulink, and System Generator is also used to ...
openaire   +1 more source

Tracking-Loop Bias Due to Costas Loop Arm Filter Imbalance

IEEE Transactions on Communications, 1982
An expression is derived which shows that when the bandpass filter preceding a Costas loop is not symmetric and the arm filters are not balanced, a static phase error, which becomes larger as the SNR decreases, can occur due to noise. Conversely, if either condition does not apply, then no noise-induced phase error bias will exist.
openaire   +1 more source

Conventional Costas Loop for QPSK

2017
The operating principle of the conventional Costas loop for QPSK is explained (other types of Costas loops for QPSK are discussed in Chaps. 6 and 9). Dynamic behavior of the loop is described using a novel mathematical model developed by the author. This new model allows the designer of a Costas loop to explicitly compute important key parameters (lock
openaire   +1 more source