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.

Coding of advanced TV for BISDN using multiple subbands

Abstract: A subband-based coding scheme for the digital transmission of advanced television (ATV) signals within broadband ISDN (BISDN) is described. It is intended for the delivery of high-quality video to the home or office at the CCITT recommended H4 rate of roughly 130 Mb/s. The scheme uses intrafield processing only, resulting in relatively low complexity for hardware implementation, very desirable error propagation properties and the elimination of motion-related artifacts. The use of the shortest kernal (two-tap) quadrature mirror filter (QMF) pairs for signal decomposition and reconstruction minimizes quantization noise spread and further reduces complexity. Through successive QMF operations, the signal is decomposed into six bands to achieve low noise coding not normally associated with the shortest kernal implementations. In effect, the coding scheme is identical to a Hadamard transform (HT) with nonconstant block sizes. When combined with entropy coding, this approach achieves the roughly 5.6:1 compression desired while retaining very high image quality. >

Quadrature amplitude modulation wave demodulator provided with band-pass filters for fixed equalizer

Abstract: A quadrature amplitude modulation wave demodulator which includes a fixed equalizer having a first band-pass filter applied with a quadrature amplitude modulation wave reception signal for outputting an in-phase component with respect to a carrier wave for the reception signal, and a second band-pass filter applied with the reception signal for outputting a quadrature component with respect to the carrier wave for the reception signal. There is provided a vector multiplication section for performing vector multiplication between one vector having outputs of the first and second band-pass filters as two components, and another vector having two reference carrier waves in quadrature to each other as two components.

Quadrature detector, quadrature demodulator using the same, and sampling quadrature demodulator

Abstract: PROBLEM TO BE SOLVED: To detect an orthogonal phase error between an in-phase signal and an orthogonal signal of a quadrature demodulator. SOLUTION: A multiplier 122 produces a product of the in-phase signal from which a low-frequency component is eliminated by a first high-pass filter 111 and the orthogonal signal from which the low-frequency component is eliminated by a second high-pass filter 112. The orthogonal phase error can be detected by the signal from which an output high-frequency component is eliminated by a low-pass filter 131. COPYRIGHT: (C)2010,JPO&INPIT

Two-Channel Parallelogram QMF Banks Using 2-D NSHP Digital All-Pass Filters

Abstract: This paper presents a novel structure for the analysis and synthesis filters of two-channel parallelogram quadrature mirror filter (PQMF) banks. Two-dimensional recursive digital all-pass filters (DAFs) with nonsymmetric half-plane (NSHP) support regions are used as the basic sections for building this structure. With an appropriate combination of the 2-D NSHP DAFs, the resultant analysis/synthesis filters possess a 2-D doubly complementary symmetry that facilitates the design and implementation of two-channel PQMF banks. Moreover, the proposed PQMF bank provides approximately linear-phase response without magnitude distortion. The design problem of the proposed PQMF bank is appropriately formulated to result in a minimization of the linear-phase error associated with the 2-D NSHP DAFs in the pth-norm (Lp) sense. Efficient design techniques are developed to solve the Lp optimization problems. Simulation results for illustration and comparison are also provided.