A study of digital techniques for signal processing

Analysis and definition of digital techniques for signal processin

Improving QPSK Transmission In Band-Limited Channels With Interchannel Interference Through Equalization

This paper describes the use of equalization in conjunction with channel filtering to improve QPSK transmission subject to both InterSymbol interference (ISI) and interchange interference (ICI). Performance bounds are computed using the nonclassical Gauss-quadrature rule (GQR) method. The signal-to-noise ratio (SNR) gain due to linear equalization over Non equalization is thereby obtained and presented. The performance of a linear equalizer thus obtained is compared with the Viterbi algorithm sequence estimator (VASE). In the absence of bounds for the VASE receiver under the channel conditions considered, simulation results are used to make the comparison. With a possible difference in the accuracies of the performance thus obtained it is shown that the VASE provides improved performance over the linear equalizer under the channel conditions considered. Copyright © 1977 by The Institute of Electrical and Electronics Engineers, Inc

Weyl-Heisenberg Spaces for Robust Orthogonal Frequency Division Multiplexing

Design of Weyl-Heisenberg sets of waveforms for robust orthogonal frequency division multiplex- ing (OFDM) has been the subject of a considerable volume of work. In this paper, a complete parameterization of orthogonal Weyl-Heisenberg sets and their corresponding biorthogonal sets is given. Several examples of Weyl-Heisenberg sets designed using this parameterization are pre- sented, which in simulations show a high potential for enabling OFDM robust to frequency offset, timing mismatch, and narrow-band interference

A study of digital techniques for signal processing Semiannual status report, 1 Feb. - 31 Jul. 1970

Adaptive array processing, dynamic programming, digital data transmission, recursive adaptive equalizers, and finite memory communication system

Performance of optimum detector structures for noisy intersymbol interference channels

The errors which arise in transmitting digital information by radio or wireline systems because of additive noise from successively transmitted signals interfering with one another are described. The probability of error and the performance of optimum detector structures are examined. A comparative study of the performance of certain detector structures and approximations to them, and the performance of a transversal equalizer are included

Communication sciences Semiannual report, 1 Jul. - 31 Dec. 1965

Statistical communication theory for learning and adaptive system programs, and signal desig

Ripple distribution for nonlinear fiber-optic channels

We demonstrate data rates above the threshold imposed by nonlinearity on conventional optical signals by applying novel probability distribution, which we call ripple distribution, adapted to the properties of the fiber channel. Our results offer a new direction for signal coding, modulation and practical nonlinear distortions compensation algorithms

Algorithmic Computability of the Capacity of Gaussian Channels with Colored Noise

Designing capacity-achieving coding schemes for the band-limited additive colored Gaussian noise (ACGN) channel has been and is still a challenge. In this paper, the capacity of the band-limited ACGN channel is studied from a fundamental algorithmic point of view by addressing the question of whether or not the capacity can be algorithmically computed. To this aim, the concept of Turing machines is used, which provides fundamental performance limits of digital computers. t is shown that there are band-limited ACGN channels having computable continuous spectral densities whose capacity are non-computable numbers. Moreover, it is demonstrated that for those channels, it is impossible to find computable sequences of asymptotically sharp upper bounds for their capacities