Development of a method for synthesis the FIR filters with a cascade structure based on genetic algorithm

The object of research is the process of digital signal processing. The subject of research is methods of synthesis of digital filters with a finite impulse response based on a genetic algorithm. Digital filtering is one of the tasks of digital signal processing. FIR filters are always stable and provide a constant group delay. There are various methods for synthesizing digital filters, but they are all aimed at synthesizing filters with a direct structure. One of the most problematic areas of a digital filter with a direct structure in digital processing is the high sensitivity of the filter characteristics to inaccuracies in setting the filter coefficients. Genetic algorithm-based filter synthesis methods use an ideal filter as the approximated filter. This approach has a number of disadvantages: it complicates the search for an optimal solution; computation time increases. The study used random search method, which is the basis of genetic algorithm (used for solving optimization problems); theory of digital filtering in filter analysis; numerical methods for modeling in a Python program. Prepared synthesis method FIR filter with the cascade structure, which is less sensitive to the effect of finite bit width. Computation time was reduced. This is due to the fact that the proposed method searches for the most suitable filter coefficients based on a genetic algorithm and has a number of features, in particular, it is proposed to use a piecewise-linear function as an approximated amplitude-frequency response. This makes it possible to reduce the number of populations of the genetic algorithm when searching for a solution. The synthesis of an FIR filter with a cascade structure based on a genetic algorithm showed that for a 24-order filter it took about 30–40 generations to get the filter parameters close to the optimal values. In comparison with classical methods of filter synthesis, the following advantages are provided: calculations of the coefficients of a filter with a cascade structure directly, the possibility of optimizing coefficients with limited bit depth.

Digital Filtering Techniques for Performance Improvement of Golay Coded TDM-FBG Sensor

For almost a half-decade, the unique autocorrelation properties of Golay complementary pairs (GCP) have added a significant value to the key performance of conventional time-domain multiplexed fiber Bragg grating sensors (TDM-FBGs). However, the employment of the unipolar form of Golay coded TDM-FBG has suffered from several performance flaws, such as limited improvement of the signal-to-noise ratio (SNIR), noisy backgrounds, and distorted signals. Therefore, we propose and experimentally implement several digital filtering techniques to mitigate such limitations. Moving averages (MA), Savitzky–Golay (SG), and moving median (MM) filters were deployed to process the signals from two low reflectance FBG sensors located after around 16 km of fiber. The first part of the experiment discussed the sole deployment of Golay codes from 4 bits to 256 bits in the TDM-FBG sensor. As a result, the total SNIR of around 8.8 dB was experimentally confirmed for the longest 256-bit code. Furthermore, the individual deployment of MA, MM, and SG filters within the mentioned decoded sequences secured a further significant increase in SNIR of around 4, 3.5, and 3 dB, respectively. Thus, the deployment of the filtering technique alone resulted in at least four times faster measurement time (equivalent to 3 dB SNIR). Overall, the experimental analysis confirmed that MM outperformed the other two techniques in better signal shape, fastest signal transition time, comparable SNIR, and capability to maintain high spatial resolution.

LOW POWER DIGITAL FILTERING USING ADAPTIVE APPROXIMATE PROCESSING: FIR FILTER STRUCTURES

Techniques for reducing power consumption in digital circuits have become increasingly important because of the growing demand for portable multimedia devices. Digital filters, being ubiquitous in such devices, are a prime candidate for low power design. Algorithmic approaches to low power frequency-selective digital filtering which are based on the concepts of adaptive approximate processing have been developed and formalized by introducing the class of approximate filtering algorithms in which the order of a digital filter is dynamically varied to provide time-varying stopband attenuation in proportion to the time-varying signal-to-noise ratio (SNR) of the input signal, while maintaining a fixed SNR at the filter output. Since power consumption in digital filter implementations is proportional to the order of the filter, dynamically varying the filter order is a strategy which may be used to conserve power. In this paper we introduce a class of approximate filter structures using FIR digital filter constituent elements. These filter structures are explored and shown to be an important element in the characterization of approximate filtering algorithms.

The Importance of Energy Efficiency in Engineering and Informatics

Techniques for reducing power consumption in digital circuits that underly automatic control of modern engineering systems are of paramount importance due to the simultaneously growing demands for portable multimedia devices and energy conservation. Digital filters, being ubiquitous in such devices, are thus a prime candidate for low power design. We review an algorithmic approach to low power frequency-selective digital filtering, an essential ingredient for energy efficient technological innovation in many domains.

The Importance of Energy Efficiency in Engineering and Informatics

Techniques for reducing power consumption in digital circuits that underly automatic control of modern engineering systems are of paramount importance due to the simultaneously growing demands for portable multimedia devices and energy conservation. Digital filters, being ubiquitous in such devices, are thus a prime candidate for low power design. We review an algorithmic approach to low power frequency-selective digital filtering, an essential ingredient for energy efficient technological innovation in many domains.

High Performance Digital Filtering on Modified Multiply and Accumulate Unit in Residue Number System with Special Type of Moduli

The paper proposes the implementation of digital filtering using residue number system and the modified truncated multiply and accumulate unit. The work was carried out a theoretical analysis of digital filters using residue number system arithmetic and implemented hardware simulation on FPGA. FPGA hardware simulation results show that the use of residue number system allows to increase the frequency of digital filters up to about 4 times and hardware costs reduce up to 3 times compared to using a common positional number system. The obtained results open up the possibility for efficient hardware implementation of digital filters on modern devices (FPGA, ASIC and etc.) to solve practical problems, such as noise reduction, amplification and suppression of the frequency spectrum, interpolation, decimation, equalization and many others.