Results 191 to 200 of about 14,247 (230)

Optimization of Linearly Equalized QAM

IEEE Transactions on Communications, 1987
A QAM signal transmitted over a channel with linear distortion and additive white Gaussian noise can be linearly equalized at the receiver to eliminate intersymbol interference. If the QAM signal is power constrained and a given symbol error rate is required, we show that it is possible to maximize the bit rate of this system by optimizing the symbol ...
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FPGA QAM Demodulator Design

2002
Bandwidth efficient communication systems employ highorder modulation schemes like M-ary QAM modulation for reasons of spectral efficiency. Many sophisticated signal processing algorithms are implemented in a QAM demodulator, including adaptive equalization, timing recovery, carrier recovery, automatic gain control and digital down conversion to name a
Chris Dick, Fred Harris 0001
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A multicarrier QAM modulator

IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, 2000
A multicarrier quadrature amplitude modulation (QAM) modulator has been developed and implemented with programmable logic devices. The multicarrier QAM modulator contains four CORDIC-based QAM modulators. A conventional QAM modulator needs two multipliers, one adder, and sine/cosine ROM's.
J. Vankka, M. Kosunen, I. Sanchis, K.A.I. Halonen   +3 more
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Error statistic of QAM channel in AM/QAM hybrid optical transmission

IEEE Photonics Technology Letters, 1996
The error statistic of the QAM channel in an AM/QAM hybrid optical transmission system is measured. Errors occur randomly in optical transmission without clipping. However, errors are found to occur in bursts when the impulsive noise due to clipping degrades the QAM signal's BER.
K. Maeda, K. Utsumi, K. Fujito
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Phase noise effects in QAM systems

Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97, 2002
The effects of oscillator phase noise on the performance of digital transmission systems employing QAM are investigated. The model used for the phase noise is a Wiener-Levy process which allows a moment characterization of the filtered phase noise.
CORVAJA, ROBERTO, PUPOLIN, SILVANO
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Performance of block turbo coded 16-QAM and 64-QAM modulations

Proceedings of GLOBECOM '95, 2002
We present the results of our investigation concerning the performance of block turbo codes associated with high spectral efficiency QAM modulations. By using a pragmatic approach, simulation results show that all the block turbo coded QAM modulations we have tested are at 2.9/spl plusmn/0.2 dB of their Shannon's limit.
R. Pyndiah, A. Picart, A. Glavieux
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Further Results on Adaptive Equalizer Improvements for 16 QAM and 64 QAM Digital Radio

IEEE Transactions on Communications, 1986
Channel distortions due to multipath fading are a principal source of outage for high-capacity digital radio. Time domain equalization is increasingly becoming an effective means to compensate for fading induced ISI. This paper compares the performance of transversal and decision feedback equalizers used for 16 QAM and 64 QAM digital radio systems. The
Mansoor Shafi, David J. Moore
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1024-QAM and 256-QAM Coded Modems for Microwave and Cable System Applications

IEEE Journal on Selected Areas in Communications, 1987
Low redundancy FEC coded 1024-QAM modems, staggered 1024-QAM, and 256-QAM modems for spectrally efficient (up to 8.84 bits/s/Hz) microwave and cable systems applications are described. Such a high spectral efficiency is required for CEPT-1 (2.048 Mbit/s) rate digital transmission in a single analog supergroup (SG` band as well as for other emerging ...
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NLA-QAM: A Method for Generating High-Power QAM Signals Through Nonlinear Amplification

IEEE Transactions on Communications, 1982
A generalized technique for generating quadrature amplitude modulated (QAM) signals that permits nonlinear amplification is presented. With this technique a high-power 2^{2n} -state QAM signal is generated by combining n unfiltered, nonlinear amplified, QPSK signals, n being a positive integer.
Douglas H. Morais, Kamilo Feher
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Statistics of companding noise for QAM transmission

IEEE Transactions on Communications, 1996
In modern voiceband data communication, the received signal is subject to nonlinear quantization noise due to companding. Under certain conditions, this quantization noise may become dominant and cause serious degradation in performance. In order to design better signal constellations for this environment, it is of interest to characterize this noise ...
Jeffrey Davidson, Irving Kalet
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