Home  About us  Contact
 

Quadrature Amplitude Modulation (quadrature + amplitude_modulation)

Distribution by Scientific Domains
Engineering100%

Selected Abstracts

On the effects of interpolator window shape and symbol location on the BER of diversity PSAM 16-QAM

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 4 2007
Lingzhi Cao
We consider pilot symbol assisted modulation (PSAM) implemented with a sinc interpolator. The sensitivity of the error rate performance to different window functions applied to the sinc interpolator is investigated. The bit error rates (BERs) for diversity M -ary quadrature amplitude modulation (MQAM) with different window functions applied to the sinc interpolator are compared. The Kaiser window is found superior to the other windows considered. A thorough discussion of the dependency of the BER performance on the symbol location is also given. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Angle differential-QAM scheme for resolving phase ambiguity in continuous transmission system

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 6 2008
Jeng-Kuang Hwang
Abstract An angle differential quadrature amplitude modulation (ADQAM) scheme is proposed to solve phase ambiguity problem in non-data-aided continuous transmission system with square QAM constellation. Starting from the 16-ADQAM case, we derive differential encoding and decoding schemes in terms of two differential angles and use a solar system analogy for explanation. The 16-ADQAM system incurs only about 0.5-dB performance degradation compared with the coherent 16-QAM system under AWGN channel. Generalization of flat fading channel and higher-level ADQAM is straightforward. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Performance evaluations of microwave power amplifiers with single- and multi-carrier quadrature amplitude modulations

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2006
Chien-Chang Huang
Abstract This article presents the performance evaluations of microwave power amplifiers (PAs) for different kinds of quadrature amplitude modulation (QAM) schemes including ,/4-DQPSK and 16-QAM for single-carrier formats and orthogonal frequency division multiplexing (OFDM) for multi-carrier configuration, by using the time-domain signal processing technique and the hybrid Volterra analysis. The influences due to various peak-to-average power ratios (PAPRs) of the modulation signals for the PA performances such as output powers, adjacent channel power ratios (ACPRs), and error vector magnitudes (EVMs) are shown with experimental verifications. A figure-of-merit of PAs based on linearity and efficiency is presented to establish a criterion for choosing the best working condition. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2375,2378, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22020 [source]