An adaptive, high-order, notch filter using all pass sections (original) (raw)

Multiple fully adaptive notch filter design based on allpass sections

IEEE Transactions on Signal Processing, 2000

We develop a canonical, adaptive cascade-structure IIR notch filter to detect and track multiple time-varying frequencies in additive white Gaussian noise. The algorithm uses allpass frequency transformation filters and a truncated gradient. Simulations indicate that our algorithm is computationally simple, converges rapidly, and has good frequency resolution

Tracking analysis of a generalized adaptive notch filter

IEEE Transactions on Signal Processing, 2000

The paper presents results of local performance analysis of a generalized adaptive notch filter (GANF). GANFs are used for identification/tracking of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. The tracking properties of the algorithm are studied analytically using a direct averaging approach and an approximating linear filter technique. Even though restricted to a single-frequency case, the presented analysis provides valuable insights into the tracking mechanisms of GANF, including the associated speed/accuracy tradeoffs, the achievable performance bounds, and tracking limitations. In addition, it allows one to formulate some useful rules of thumb for choosing design parameters.

Generalized adaptive notch filters with improved tracking capabilities

14th IFAC Symposium on System Identification, 2006, 2006

Bias (lag) errors seriously limit tracking capabilities of adaptive filters. We show that frequency biases, which arise in generalized adaptive notch filtering algorithms, can be reduced if the frequency estimates are appropriately filtered. This allows one to build estimation schemes with improved tracking capabilities.

Adaptive IIR Notch Filters for tracking of quasi-harmonic signals

2012 Proceedings of the 20th European Signal Processing Conference, 2012

In this paper, a new procedure for the design of a cascade of IIR Adaptive Notch Filters (ANFs) is presented. The cascade is composed by second-order sections of modified Nehorai Constrained ANFs, with coefficients modeled by a single polynomial of arbitrary order. This approach allows for a design with less parameters to control notch positions than the number of cascaded sections. The resulting structure is particularly suitable for tracking components of quasi-harmonic signals. An example shows that the coefficient modeling can tackle the inherent inharmonicity of the notes emitted by a string instrument. Finally, a complete adaptation algorithm for the model parameters, derived from Nehorai's ANF recursive prediction error algorithm, is described.

Frequency tracking using constrained adaptive notch filters synthesised from allpass sections

1990

New constrained adaptive notch filter structures are proposed. These structures are synthesised from allpass filter sections, which are realised as structurally lossless bounded real functions with a minimum number of delay elements and multipliers. Both structures admit orthogonal tuning of their notch frequency and bandwidth. Frequency tracking is achieved simply by the evaluation of a function of a filter parameter. Connections are shown with the structures used by other workers. Signal enhancement outputs are obtained from both structures and their signal-tonoise improvement ratios are given. The mirrorimage pair of polynomials present in a real allpass transfer function is shown to provide a significant simplification in the generation of the necessary gradient terms used in parameter adaptation. Simulations are included to verify the performance of these structures when they are used to track both single and multiple sinusoids in additive broadband noise.

Signal tracking properties of a class of adaptive notch filters

2005 13th European Signal Processing Conference, 2005

The signal tracking properties of two adaptive notch filtering algorithms are studied analytically using a linear filter approximation technique. Even though restricted to a single frequency case, the presented analysis provides valuable insights into the tracking mechanisms, including the speed/accuracy tradeoffs, the achievable performance bounds, and tracking limitations of the analyzed algorithms. Additionally, it allows one to formulate some useful rules of thumb for choosing design parameters.

Analysis and performance evaluation of an adaptive notch filter

IEEE Transactions on Information Theory, 1984

adaptive notch filter is derived by using a general prediction error framework. The proposed infinite impulse response filter has a special structure that guarantees the desired transfer characteristics. The filter coefficients are updated by a version of the recursive maximum likelihood algorithm. The convergence properties of the algorithm and its asymptotic behavior are discussed, and its performance is evaluated by simulation results.

Direct frequency estimation based adaptive algorithm for a second-order adaptive FIR notch filter

Signal Processing, 2008

This work deals with the problem of the frequency estimation of a sinusoidal signal corrupted by broad-band noise. The direct frequency estimation based adaptive algorithm for a second-order adaptive finite impulse response (FIR) notch filter (AFNF) is thus proposed. The proposed algorithm employs the bias removal technique to remove the bias existing in the estimated parameter. The performances including the rate of convergence and the mean square error (MSE) can be easily controlled by using only one parameter, i.e., step size parameter. Moreover, the proposed filter is simple to implement and suitable for real-time applications. In addition, the difference equations for the convergence in the mean and mean square, and the closed form expressions for the steady-state estimation bias and MSE are also carried out. Finally, the simulation results are provided to confirm the theoretical analysis. r

A minimal parameter adaptive notch filter with constrained poles and zeros

ICASSP '85. IEEE International Conference on Acoustics, Speech, and Signal Processing, 1985

Abstmt-A new algorithm is presented for adaptive notch filtering and parametric spectral estimation of multiple narrow-band or sine wave signals in an additive broad-band process. The algorithm is of recursive prediction error (RPE) form and uses a special constrained model of infinite impulse response (IIR) with a minimal number of parameters. The convergent fdter is characterized by highly narrow bandwidth and uniform notches of desired shape. For sufficiently large data sets, the variances of the sine wave frequency estimates are of the same order of magnitude as the Cramer-Rao bound. Results from simulations illustrate the performance of the algorithm under a wide range of conditions.

Design and Development of Adaptive filter for Real Time Signal Processing

IOP Conference Series: Materials Science and Engineering, 2021

In Communication the signal is distorted due to noise and the notch filters are used for eliminating unwanted frequencies For filtering the signal in a specific band Notch filter is used. Notch filter can pass the signal below and above notch frequency. In most of the signal processing applications frequency estimation of narrow band signals in noisy environment are required For frequency detection and tracking Adaptive IIR filter or Adaptive FIR filters can be used. Adaptive FIR Filter is more stable than Adaptive IIR filter. In most practical applications Adaptive IIR Notch Filter (AIIRNF)is used The advantage of Adaptive IIR notch filter over FIR Filter is less number of filter coefficients and less complexity in design In this paper Adaptive IIR Notch filter is designed for real time applications. The performance of designed adaptive IIR Notch filter is evaluated based on Magnitude and Frequency response.