Quadrature mirror filter

About: Quadrature mirror filter is a research topic. Over the lifetime, 955 publications have been published within this topic receiving 28900 citations.

Wavelet Denoising by Using Linear-Phase NPR-QMF Banks

Abstract: In this paper we compare the near-perfect reconstruction (NPR) quadrature mirror filter (QMF) design, versus perfect reconstruction (PR)-QMF design in terms of the flexibility of the design and the design filter characteristics, and their efficiency for denoising of the signals based on wavelet shrinkage technique.

Comparison of Multirate two-channel Quadrature Mirror Filter Bank with FIR Filters Based Multiband Dynamic Range Control for audio

Abstract: This paper proposes a Comparison of Multirate two-channel Quadrature Mirror Filter QMF bank with FIR filters based Multiband Dynamic Range Control DRC for audio. Two-channel QMF decomposes input audio signals into low and high frequency bands with the help of analysis filters, and these sub-bands are decimated by a factor of 2 and inputted to DRC up-sampled by a factor of 2 after which need to be combined to reconstruct the original signal with the help of synthesis filters with increased amplitude in the audio compared to when only FIR filters are used. The filters used here are Finite Impulse Response FIR using Kaiser Window. The reconstructed signal is an exact replica of input signal with some delay called perfect reconstruction. In DRC, multi-band compressor is used to apply compression differently to different frequency bands of the input signal, which uses minimum gain method. This allows the user to be selective about how compression is applied to a signal and only add power to certain parts of the frequency spectrum. Here limiter, compressor, expander and noise gate are used in the DRC, which protects the AD converter from overload. Index Terms: Analog to digital converter (A/D), Dynamic Range Control (DRC), Finite Impulse Response (FIR), Quadrature Mirror Filter (QMF).

Phase error compensation method for reception and/or transmission system with in-phase and quadrature signal paths

Abstract: The phase error compensation method uses a phase corrector (PC) inserted in the digital signal processing stage (10') for the in-phase and quadrature signal paths, for calculation of phase-corrected in-phase and quadrature signal components using matrix operations. An Independent claim for a reception and/or transmission system with in-phase and quadrature signal paths is also included.

Low-Complexity Algorithm of Recursive Analysis and Synthesis Quadrature Mirror Filterbanks for Digital Radio Mondiale

Abstract: This paper proposed a low-complexity algorithm and of analysis and synthesis quadrature mirror filter banks (AQMF, SQMF) on the spectral band replication (SBR) for digital radio mondiale (DRM). Based on recent Lai et al.'s concept, an extended issue is addressed form the view point of recursively computing the AQMF and SQMF coefficients. The proposed recursively computational method not only combines with the lifting scheme algorithm but also employs the fixed-coefficient concept to introduce the technique of canonical signed digit (CSD) multiplication. The results show that the proposed QMFs algorithm has a great improvement on multiplication of computational complexity. For the recursive kernel computation (N=64), the proposed method can transfers the constant multiplication into addition by using CSD technique which brings a great improvement in the complexity of multiplication and the requirement of coefficient. The overall complexity of the proposed algorithm (N=64) has 93.46% reduction of multiplication and 73.73% reduction of coefficient. It would be more efficient and more suitable than previous works for DRM applications.

Mirroring Properties of Sub-band Adaptive Beamforming Arrays using Quadrature Mirror Filter Banks

Abstract: The concept of the sub-band adaptive beamforming arrays (ABA) is derived from the conventional fullband adaptive antenna arrays. Instead of doing the beamforming for the entire frequency band as in the full band ABA, only one sub-band of the frequency band is subjected to the same in here. The sub-banding of the full frequency band is done here by a quadrature mirror filter (QMF) bank. In a previous attempt, an approximate method has been proposed to reproduce the higher sub-band output from the lower sub-band output [1]. However, the higher sub-band has higher centre frequency, which demands higher Nyquist bandwidth. This will increase the operational complexity of the sub-band ABA. Recently it has been shown that the QMF sub-band adaptive beamforming can be performed by optimising the higher sub-band output and then, multiplying the signal output with a transforming factor that generates the lower sub-band output [2]. The lower frequency band requires only lower Nyquist bandwidth. It is believed that this will reduce the hardware complexity, the cost and the workload of the earlier version of the QMF sub-band ABA system [1]. In this work, a hardware implementation and its characteristics of such a sub-band ABA to generate the combined output from the higher sub-band is investigated.