Improvement of LMS adaptive noise canceller using uniform Poly-phase digital filter bank

<span>This paper presents the Least Mean Square (LMS) noise canceller using uniform poly-phase digital filter bank to improve the noise can-cellation process. Analysis filter bank is used to decompose the full-band distorted input signal into sub-band signals. Decomposition the full-band input distorted signal into sub-band signals based on the fact that the signal to noise ratio (S/N) is inversely proportional to the signal bandwidth. Each sub-band signal is fed to individual LMS algorithm to produce the optimal sub-band output. Synthesis filter bank is used to compose the optimal sub-band outputs to produce the final optimal full-band output. In this paper, m-band uniform Discrete Fourier Transform (DFT) digital filter bank has been used because its computational complexity is much smaller than the direct implementation of digital filter bank. The simulation results show that the proposed method provides the efficient performance with less and smooth error signal as compared to conventional LMS noise canceller.</span>

Implementation of Cosine Modulated Digital Filter Bank on Processor with ARM Architecture

This paper presents a class of multichannel cosine-modulated filter banks (CMFB) of analysis based on the modulation effect with a fast discrete-cosine transformation of the fourth type (DCT-IV), which is calculated using the fast Fourier transform. As a prototype filter, a low-frequency filter with a finite pulse characteristic was used, frequency-shifted copies of which were made using an effective technology for polyphase representation of the filter Bank. The comparison of the number of arithmetic operations performed by digital down converter (DDC) based on cascade integral-comb (CIC) and CMFB based on different number of channels is given. A software description of the CMFB algorithm is presented in the form of block diagrams describing the capabilities of the Opencl and clfft software libraries for implementing the DCT-IV filter Bank and modulation algorithm on a GPU. The obtained algorithm was tested on an ARM family processor and a mali GPU with a table with sample rate for different number of channels with the maximum load of the graphics processor (GPU) and the minimum load of the Central processor (CPU).