Introduction Active notch filters have been used in the past for applications like elimination of 50and 60-Hz hum components. They have proven to be somewhat problematic from the standpoints of center frequency (f0) tuning, stability, and repeatability. The advent of high-speed amplifiers opens the possibility of higher-speed notch filters—but are they actually producible? This article will sho...

A new method for the design of multiple notch filters is presented using an all-pass filter of order 2N, N being the number of notch frequencies. The all-pass filter is realized as a cascade of N second-order all-pass sections. Besides meeting the notch frequency specifications exactly, the method ensures that the realized 3-dB bandwidths are lower than those specified. Illustrative examples ar...

A new IIR adaptive notch filter (ANF) with fast convergence rate, accurate estimation of notch frequencies, and modest realization complexity is presented in this paper. The problem of obtaining a notch filter from a given signal containing multiple sine waves in noise is first formulated as the conventional problem of system identification. Then the new ANF is developed via the algorithm of St...

In signal processing it is often required to have multiple-notch filters which simultaneously possess a very selective magnitude response and a transient response of short duration. Multiple-notch filters are usually used to remove the powerline hum and its harmonics. It is known, that sharper notches are obtained by either using more coefficients in FIR filters, or by placing the pole closer t...

Radio Frequency Interference (RFI) suppression is an important technique in the ultra-wideband synthetic aperture radar (UWB SAR). In this paper, we mainly analyze the performance of a notch filter for RFI suppression. The theoretical output from notch filter is presented based on RFI signal’s narrowband property. The research conclusion shows that the notch filter has significant effect on sid...

Two novel adaptive notch filters are presented. The updating algorithms are based on the Steiglitz-McBride error criterion minimization and the basic realizations of the notch filters are all-pass based lattice filters. The proposed realizations represent an extension of a previous ad-hoc scheme for adaptive notch filtering and avoid finding the roots of a high order polynomial to obtain the un...

Chaotic motion can sometimes be desirable or undesirable, and hence control over such a phenomenon has become a topic of considerable interest. Currently available methods involve making systematic time-varying small perturbations in the system parameters. A new method is presented here to achieve control over chaotic motion using notch filter output feedback control. The notch filter controlle...

In this paper we propose the use of a lattice based second order infinite impulse response (IIR) notch filter with a simplified adaptation algorithm for removal of power line frequency from ECG signals. The performance of this filter is better as compared to a second order infinite impulse response (IIR) notch filter for a real time ECG recording systems where the frequency of line varies over ...

We demonstrate a highly tunable deep notch filter realized in a liquid-crystal photonic-bandgap (LCPBG) fiber. The filter is realized without inducing a long-period grating in the fiber but simply by filling a solid-core photonic-crystal fiber with a liquid crystal and exploiting avoided crossings within the bandgap of the LCPBG fiber. The filter is demonstrated experimentally and investigated ...

This paper investigates an H-fractal wideband microstrip filter with multi-passbands and a tuned notch band for wireless communication frequencies. The four different filter configurations explored are: symmetric with zero offset, symmetric with nonzero offset, asymmetric with zero offset, and asymmetric with nonzero offset. The effect of H-fractal iterations, fractal scaling parameters, and st...