Design Of Digital Notch Filters Research Articles

Nonseparable Three-Dimensional IIR Notch Filter Design Using Outer Product Expansion

This brief emphasizes on the 3-D digital notch filter design problem. A standard form of notch filter design is presented in nonseparable form. A rank reduction technique is conducted to expand the 3-D design problem. The 3-D digital notch problem is initially expanded into the 2-D and 1-D filter design problems. Then, the 2-D problem is expanded again into two 1-D problems by using the singular value decomposition technique. A simple algebraic method is subsequently used to approximate and design each 1-D infinite impulse response (IIR) notch filter. These individual 1-D IIR notch designs are finally combined to construct a standard form of 3-D digital notch filter design. The purposed system not only has a closed-form transfer function but also satisfies bounded-input-bounded-output stability condition. At the end of this brief, the simulation of the purposed magnitude response is presented, together with implementation on a 3-D image.

Analytical two-dimensional IIR notch filter design using outer product expansion

This work is concerned with the two-dimensional (2-D) digital notch filter design problem. First, the outer product expansion is used to reduce the 2-D notch filter design problem to two pairs of one-dimensional (1-D) filter design problems. Then, we develop a simple algebraic method for the design of two pairs of 1-D IIR filters. This approach not only has closed form transfer function but also satisfies bounded input/output (BIBO) stability condition. Finally, one example is included to illustrate the proposed design method, and the 2-D IIR notch filter is applied to eliminate the sinusoidal interference superimposed on an image.

Design and implementation of efficient IIR notch filters with quantization error feedback

Straightforward methods for the design of digital notch filters are presented. The design method is based on setting a zero of the filter at a notch frequency and placing a pole in its neighborhood such that the notch width is narrow enough while keeping the group delay of the filter sufficiently flat. A technique for efficient and well-behaved implementation with fixed-point signal processors is advanced, based on the use of quantization error feedback for roundoff noise reduction. The design approach is illustrated with numerical examples, and an assembly-language program for the family of TMS320 signal processors is provided. >

Adaptive digital notch filter design on the unit circle for the removal of powerline noise from biomedical signals

This paper investigates adaptive digital notch filters for the elimination of powerline noise from biomedical signals. Since the distribution of the frequency variation of the powerline noise may or may not be centered at 60 Hz, three different adaptive digital notch filters are considered. For the first case, an adaptive FIR second-order digital notch filter is designed to track the center frequency variation. For the second case, the zeroes of an adaptive IIR second-order digital notch filter are fixed on the unit circle and the poles are adapted to find an optimum bandwidth to eliminate the noise to a pre-defined attenuation level. In the third case, both the poles and zeroes of the adaptive IIR second-order filter are adapted to track the center frequency variation within an optimum bandwidth. The adaptive process is considerably simplified by designing the notch filters by pole-zero placement on the unit circle using some suggested rules. A constrained least mean-squared (CLMS) algorithm is used for the adaptive process. To evaluate their performance, the three adaptive notch filters are applied to a powerline noise sample and to a noisy EEG as an illustration of a biomedical signal.

Two dimensional IIR digital notch filter design

In this paper, the two dimensional (2D) IIR digital notch filter design problem is investigated. First, we develop a simple algebraic method for 2D IIR notch filter design. This approach not only has closed-form transfer function but also satisfies the bounded-input/bounded-output (BIBO) stability condition. Next, we apply the 2D notch filter to eliminate sinusoidal/narrowband interferences superimposed on an image. Simulation results are presented to demonstrate the effectiveness of this approach. >

Corrections on "Two dimensional IIR digital notch filter design"

There are four figures misplaced in the above paper. The correction is as follows: Fig. 4(e) needs to be interchanged with Fig. 5(a), and Fig. 5(b) needs to be interchanged with Fig. 7(a).

Design of digital notch filters

It is shown that a second-order digital notch filter is uniquely characterized by two distinct parameters, the notch frequency and the 3-dB rejection bandwidth. As a result, such a filter can be realized using only two multipliers. Methods are outlined to design a notch filter for a prescribed notch frequency and a prescribed 3-dB rejection bandwidth, along with procedures for postdesign adjustment of these parameters. All two-multiplier, canonic and noncanonic, notch filter configurations are developed using the multiplier extraction approach. These networks are then compared with regard to the effect of internal multiplication roundoff errors. Results of computer simulation of the notch filter configurations are also included.

Digital notch filter design procedure

An analytical procedure for designing a linear digital notch filter is presented. The resultant filter is sixth-order and is implemented by cascading three second-order filters so as to avoid instability which may arise from computer coefficient truncation. The procedure outlined is straightforward, requires only simple algebraic steps, and gives filter parameter selection criteria for reducing the effects of computer coefficient truncation. Notch filters have utility in situations where a desired signal is corrupted by an additive sinusoidal pickup. One thus must process the noisy signal so as to remove the sinusoid without significantly distorting the desired signal.