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Notch filter designer5/16/2023 ![]() An improved time-varying pole radius IIR notch filter was proposed in . This resulted in a wide notch width during the first few samples and as the transient becomes minimal, notch width becomes narrower. Starting with a small pole radius value, a function, varying in time, was used to gradually increase the pole radius to the desired value. Piskorowski proposed a solution in order to suppress the initial transient by varying the notch bandwidth with time . The narrower the IIR notch filter bandwidth is, the longer is the transient response . The duration of the transient response is dependent on the filter order hence the low-order notch filter is the preferred choice of designer. However, the IIR notch filter exhibits a transient response which may corrupt the initial portion of the processed signal. In order to reduce computational complexity and signal process delay, an IIR notch filter is preferred over FIR. The digital notch filter can be designed using the finite impulse response (FIR) or the infinite impulse response (IIR) form. In the global navigation satellite system, the notch filter is a part of the interference detection unit, where it determines the disturbing signals for improving positional accuracy . The notch filters are also used in power electronics devices for extracting fundamental frequency component of the load current . The notch filters are employed to obtain enhanced ECG signals after measurement . Due to low amplitude and frequency range, noise is induced from a power line in such signals. The bioelectrical signals, such as ECG, gets corrupted during the data acquisition stage. It is mainly used to remove a specific frequency component from the signal. The suggested LWDNF is then implemented on a field-programmable gate array using a Xilinx system generator for the DSP design suite.Ī narrow bandwidth band-stop filter whose magnitude response takes the shape of a notch is termed as a notch filter. Thus, the proposed lattice wave digital notch filter (LWDNF) produces better results compared to the existing literature in terms of error analysis. Moreover, the LWDF is less sensitive to the word-length effects. Therefore, the number of memory locations required to implement the proposed design is reduced by half. The advantage of using a LWDF structure is that only one coefficient has variable values to vary the notch width with time. Such a filter requires two variable coefficients for varying the notch width with time. Previously, the IIR structure has been used for implementing the time varying bandwidth notch filter. This results in minimised transient duration notch filter with a sufficiently high-quality factor. As time moves forward, the notch bandwidth reduces to attain the possible minimum width. During the initial samples, the notch filter has a wide bandwidth in order to diminish signal transient. For reducing the initial signal transient, the variable notch bandwidth filter is designed. In this study, the design and field-programmable gate array (FPGA) implementation of the digital notch filter with the lattice wave digital filter (LWDF) structure is presented. IET Generation, Transmission & Distribution.IET Electrical Systems in Transportation.IET Cyber-Physical Systems: Theory & Applications.IET Collaborative Intelligent Manufacturing.CAAI Transactions on Intelligence Technology.
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