Showing papers by "Kenneth Steiglitz published in 1992"

Suppression of near- and far-end crosstalk by linear pre- and post-filtering

Abstract: Full-duplex data communication over a multi-input/multi-output linear time-invariant channel is considered. The minimum mean square error (MMSE) linear equalizer is derived in the presence of both near- and far-end crosstalk and independent additive noise. The MMSE equalizer is completely specified in terms of the channel and crosstalk transfer functions by using a generalization of previous work due to Salz (1985). Conditions are given under which the equalizer can completely eliminate both near- and far-end crosstalk and intersymbol interference. The MMSE transmitter filter, subject to a transmitted power constraint, is specified when the channel and crosstalk transfer functions are bandlimited to the Nyquist frequency. Also considered is the design of MMSE transmitter and receiver filters when the data signals are arbitrary wide-sense stationary continuous or discrete-time signals, corresponding to the situation where the crosstalk is not phase-synchronous with the desired signal. >

METEOR: a constraint-based FIR filter design program

Abstract: It is proposed to specify a filter only in terms of upper and lower limits on the response, find the shortest filter length which allows these constraints to be met, and then find a filter of that order which is farthest from the upper and lower constraint boundaries in a minimax sense. The simplex algorithm for linear programming is used to find a best linear-phase FIR filter of minimum length, as well as to find the minimum feasible length itself. The simplex algorithm, while much slower than exchange algorithms, also allows the incorporation of more general kinds of constraints, such as concavity constraints (which can be used to achieve very flat magnitude characteristics). Examples are given to illustrate how the proposed and common approaches differ, and how the proposed approach can be used to design filters with flat passbands, filters which meet point constraints, minimum phase filters, and bandpass filters with controlled transition band behavior. >

Error detection in arrays via dependency graphs

Abstract: This paper describes a methodology based on dependency graphs for doing concurrent run-time error detection in systolic arrays and wavefront processors. It combines the projection method of deriving systolic arrays from dependency graphs with the idea of input-triggered testing. We call the method ITRED, forInput-driven Time-Redundancy Error Detection. Tests are triggered by inserting special symbols in the input, and so the approach gives the user flexibility in trading off throughput for error coverage. Correctness of timing is proved at the dependency graph level. The method requires no extraPEs and little extra hardware. We propose several variations of the general approach and derive corresponding constraints on the modified dependency graphs that guarantee correctness. One variation performs run-time error correction using majority voting. Examples are given, including a dynamic programming algorithm, convolution, and matrix multiplication.

Run-time error detection in arrays based on the data-dependency graph

Abstract: ITRED (input-driven time-redundancy error detection), a methodology based on dependency graphs for doing concurrent run-time error detection in systolic arrays and wavefront processors, is described. It combines the projection method of deriving systolic arrays from dependency graphs with the idea of input-triggered testing. Tests are triggered by inserting special symbols in the input, and so the approach gives the user flexibility in trading off throughput for error coverage. Correctness of timing is proved at the dependency graph level. The method requires no extra processing elements and little extra hardware. The general approach is presented, and corresponding constraints on the modified dependency graphs that guarantee correctness are derived. >