This correspondence introduces a new class of infinite impulse response (IIR) digital filters that unifies the classical digital Butterworth filter and the well-known maximally flat FIR filter. New closedform expressions are provided, and a straightforward design technique is described. The new IIR digital filters have more zeros than poles (away from the origin), and their (monotonic) square m...

in this paper, a novel decision based median (dbm) filter for enhancing mr images has been proposed. the method is based on eliminating impulse noise from mr images. a median-based method to remove impulse noise from digital mr images has been developed. each pixel is leveled from black to white like gray-level. the method is adjusted in order to decide whether the median operation can be appli...

A rapid method for calculating the nearfield pressure distribution generated by a rectangular piston is derived for time-harmonic excitations. This rapid approach improves the numerical performance relative to the impulse response with an equivalent integral expression that removes the numerical singularities caused by inverse trigonometric functions. The resulting errors are demonstrated in pr...

Leveraging the relationship between Wiener filtering and the coherence function, a version of coherence is defined that captures the causal relationship between WSS processes. This causal coherence is interpreted in a modeling context and used to demonstrate what a frequency dependent measure for causality both can and can’t represent. To understand how well frequency dependent coherence spectr...

Lightning impulse measurements can be highly influenced by measurement arrangement, characteristics of high voltage divider, digitizer (transient recorder) performance, and algorithms used for parameter evaluation. The main sources of measurement errors are the non-ideal step responses of digitizer and voltage divider. This paper discusses the use of deconvolution to correct for the non-ideal s...

We consider adaptive periodic IIR ltering and present an extension of the Hyperstable Adaptive Recursive Filter (HARF). We give conditions for convergence of the parameter estimate error, involving passivity of certain operators in the identi cation loop, identi ability of the system parameters, and persistent excitation (pe). A necessary and su cient condition for identi ability is given and s...

We address the problem of optimizing the latency time for transmit filters which can have FIR or block structure. When we allow the transmission system to have latency time, we gain an additional degreeof freedom which can be exploited to improve the performance substantially. Contrary to the latency time optimization for FIR filters, the optimization for block transmit filters is very complex....

This paper derives su cient time-varying bounds on the maximum variation of the coe cients of an exponentially stable, linear, time-varying and recursive lter. The stability bound is less conservative than all previously derived bounds for time-varying IIR systems. The bound is then applied to control the step size of output error adaptive IIR lters to achieve exponentially stable operation. Ex...

This communication presents a new approach to blind equalization of a FIR channel. It is based on a boundederror assumption and takes into account the fact that the input signal is in a nite alphabet. We show that even in the noisy case, identi ability can be guaranteed in nite time, provided that the support of the noise density is suitably bounded.

The concept of cyclic filter banks was introduced independently in Ref. [1] and [2], though in [1], a different nomenclature was used. “Cyclic filter banks” is a superset of the traditional non-cyclic filter banks, and readily suggest implementation of subband filtering through DFT. In this paper we show that the DFT implementation is also advantageous for the conventional FIR filter banks. The...