Half-band Finite Impulse Response Filters Research Articles

Effects of Sampled-Values Data Quality on Responses of Time-Frequency Based Digital Relays

Time-frequency based digital protective relays can offer several advantages of high accuracy, improved reliability, and fast response over other protective relays. These protective relays employ half-band digital finite impulse response (FIR) filters to process currents and/or voltages to extract fault signatures, which facilitate accurate detection and identification of fault events. Coefficients of the employed half-band digital FIR filters are determined by wavelet or phaselet functions. The signal processing part in a time-frequency based digital protective relay processes samples of measured currents and/or voltages. As a result, attention has to be paid to the measurement, digitization, and communication of current and voltage data. Power systems utilize the IEC 61850 standard to implement data communication between measurement, control, and protection devices. This paper assesses the impacts of the IEC 61850 sampled values on the accuracy and response speed of time-frequency based digital protective relays. The presented assessment is conducted for two sample cases; the transformer differential protection and arcing current fault detection and identification. Test results show that the accuracy and response speed of time-frequency based digital protective relays are maintained, when measured currents and voltages are communicated using the IEC 61850 sampled values.

Ambient intelligence architecture of MRPM context based 12-tap further desensitized half band FIR filter for EEG signal

The half band filter constructed with cascade structure of FIR filter reduces the insensitivity of frequency response due to coefficient quantization. The coefficient insensitivity can be further reduced by desensitized half band FIR filter. A digital desensitized filter incorporates a first and a second half band filter joined in a cascade between an input and the output of the digital filter. The design for analyzing the electroencephalogram (EEG) signals with the half band finite impulse response (FIR) filter architecture. In this work the 12-tap further desensitized FIR half band employs an efficient modified Russian peasant multiplier (MRPM) with a square root carry select adder (SQRT CSLA) stage has been used to reduce the hardware in multiplier and accumulate (MAC) unit. The proposed filter design is used to analyze the EEG signals with reduced hardware in the health care monitoring for ambient environment. The proposed method offers 38.5% reduction in No. of LUTs, 47.49% reduction in No. of slices, 8.16% reduction in delay (ns) and 29.80% reduction in power (mw).

Multirate Processing Technique for Obtaining Integer and Fractional-Order Derivatives of Low-Frequency Signals

This paper proposes a multirate processing technique for obtaining integer and fractional derivatives of digital signals with an improved signal-to-quantization noise ratio. The technique consists of an oversampling analog-to-digital conversion unit with a dithering process and multistage down sampling process followed by an half-band finite impulse response (FIR) differentiator with high performance cascaded using a decimator with a factor of two. In the cascaded multistage processing, each stage contains a simple half-band low-pass FIR filter followed with decimation by two. The proposed technique uses an extremely small size for each half-band low-pass filter, hence requiring much less memory and computational complexity in comparison with the single-stage process. Computer simulations and experimental data processing demonstrate the effectiveness of the proposed method.

Equiripple Approximation of Half-Band FIR Filters

A novel design procedure of equiripple (ER) half-band (HB) finite-impulse-response (FIR) filters is developed. A solution to the approximation problem in terms of generating function and zero-phase transfer function for the ER HB FIR filter is presented. The ER HB FIR filters are optimal in the Chebyshev sense. The closed-form solution provides an efficient computation of the impulse response of the filter. One example is included.

Low-power decimator design using approximated linear-phase N-band IIR filter

This correspondence presents a new design of a low-power decimation filter, which consists of a poly-phase finite-impulse-response (FIR)-4 comb filter, an approximate linear-phase one-third-band infinite-impulse-response (IIR) filter, and a half-band FIR filter. A poly-phase FIR-4 comb filter architecture was designed, which consumes 75% less power than the recursive comb filter architecture. New general equations were derived for the design of 1/N-band IIR filters, and these equations were used to design a novel approximate linear-phase one-third-band IIR filter. The decimation filter is designed using Simulink and DSP Blockset, and Matlab simulations are performed to verify the phase linearity and magnitude response of the designed filter. The group delay for the passband region of one-third-band IIR filter has a negligible error of 0.009%. The resulting decimation filter has 60% less hardware and consumes 67% less power than the comb-FIR-FIR decimation filter.

Algebraic Design of Some Equiripple Linear-Phase Half-Band FIR Filters

Summary A closed form solution for the approximation of a linear-phase FIR (finite impulse response) filter with equiripple magnitude responsein the passband and stopband was not known. In this letter we present a closed form solution of some equiripple linear-phase half-band FIR filter approximation.

通過域等リップルハーフバンドＦＩＲフィルタの一設計法

A new algorithm for designing half-band FIR (Finite Impulse Response) filters with equi-ripple passband amplitude is developed. This algorithm is an analytical design method with which tap-gain coefficients of FIR filters are obtained by non-iterative calculation. The minimum stopband attenuation can be reduced within the limits of appropriate quantity by permitting equi-ripples in the passband without extending the transition width of FIR filters. A method to reduce the level of equi-ripples is also mentioned.

ハーフバンドＦＩＲフィルタの設計に関する一考察

The problems with conventional designing conditions and design methods for Half-band FIR (Finite Impulse Response) filters are discussed first. Then a new design method and the qualitative formation of a new designing condition are explained. This new method can be applied to not only low-pass filters but also bandpass filters, band eliminating filters, and Mth-band filters.