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.

Multidimensional Two-channel Linear Phase FIR Filter Banksand Wavelet Bases with Vanishing Moments

Abstract: In the paper new design methods for multidimensional two-channel perfect reconstruction (PR) FIR filter banks are described. The filters have linear phase, achieve an arbitrarily high number of vanishing moments and can be used to obtain biorthogonal wavelet bases. Two-dimensional wavelet bases with square, rectangular, and hexagonal support are constructed. A design method that trades off vanishing moments and frequency selectivity is described. These two properties are both important in subband coding, but they each require a share of the degrees of freedom available from the total number of filter coefficients. Novel analytic formulae are derived and are applied to provide illustrative examples.

Two-Channel Quincunx QMF Banks Using Two-Dimensional Digital Allpass Filters

Abstract: This paper presents a novel structure for the analysis and synthesis filters of two-channel quincunx quadrature mirror filter (QQMF) banks. This structure uses an appropriate combination of 2-D recursive digital allpass filters (DAFs) with symmetric half-plane (SHP) support regions. The proposed analysis/synthesis filters possess a 2-D doubly complementary half-band (DC-HB) property that facilitates the design and implementation of the proposed two-channel QQMF banks. Moreover, the proposed structure provides approximately linear-phase response without magnitude distortion. The design problem of the proposed QQMF banks is appropriately formulated to result in a linear optimization problem that only minimizes the linear-phase error associated with the 2-D SHP DAFs in the p th-norm (Lp) sense. Efficient design techniques are developed to solve the Lp optimization problem for finding the coefficients of the 2-D recursive SHP DAFs. Finally, we provide simulation results for illustration and comparison.

A new approach to the design of FIR perfect reconstruction QMF banks

Abstract: A design method for perfect reconstruction quadrature mirror filter (PR-QMF) banks based on obtaining good initializing points is presented. For the two-channel PR-QMF design, the initializing point is obtained from a traditional QMF design, while in the M-channel case (M>2), it is obtained from a pseudo-QMF design. In both cases, the parameters of the corresponding PR-QMF bank (lattice implementation) are initialized. This leads to considerably faster convergence of the optimization. Design examples are included. >

Method and apparatus for decoding input signal which encoding multi-channel to mono or stereo signal to 2 channel binaural signal

Abstract: A method and an apparatus for decoding an input signal, that a multi-channel signal is compressed as a mono or stereo signal, into a binaural signal of 2 channels are provided to simplify an operating process by synthesizing and outputting the multi-channel signal as the binaural signal of the 2 channels without a process for recovering the input signal, that the multi-channel signal is compressed as the mono or stereo signal, is recovered as the multi-channel signal in a QMF(Quadrature Mirror Filter) domain. A channel level analyzing unit(204) calculates an FBCLs(Full Band Channel Levels) of respective channels composing a multi-channel from the CLD(Channel Level Difference) of the multi-channel. A two-channel synthesizing unit(208) performs the sound image localization of channel-classified data included in an input signal in directions corresponding to the channels on the basis of the calculated FBCLs of the respective channels.

QMF implementation using Xilinx SysGen (XSG)

Abstract: The Quadrature Mirror Filter (QMF) basically is a parallel combiation of of a High Pass Filter (HPF) and Low Pass Filter (LPF), which performs the action of frequency subdivision by splitting the signal spectrum into two spectra. Thus QMF finds wide applications in many signal processing tasks such as transmultiplexing1, equalizing wireless communication channels; sub-band coding of speech and image signals, sub-band acoustic echo cancellation etc[1,2]. Hence this paper is devoted to the effective utilization of XSG for hardware implementation of QMF. This assists the Xilinx IP Core generator to deliver the optimized results for the implemented device within short duration of time. The results obtained in the simulation of QMF using XSG and the communication system built using QMF at transmitter and receiver side indicate that the nearly ‘Perfect Reconstruction’ is possible without any effect of aliasing. The obtained Synthesis Report for implemented QMF indicates that the utilization of sililcon die area and power dissipation, for Spartan 3E device, are sufficiently low. Also the comparison between the results of XSG and Simulink depicts that it is efficient to built QMF using XSG. The study reveals that QMF-DPCM provides much better approach towards the communication system. DPCM using QMF is introduced to pave the way for smooth transition from conventional 4 kHz band telephone systems to 7 kHz wide-band systems[3].