A versatile multichannel filter bank with multiple channel bandwidths (original) (raw)

Configurable Multirate Filter Banks

American Journal of Applied Sciences, 2008

Multimedia communications require efficient and real-time implementations of multirate digital signal processing systems. The backbone structures of multirate systems are digital multirate filter banks. Therefore, efficient multimedia communications rely, in the first place, on real-time implementations of multirate filter banks. In this paper, we describe a Field Programmable Gate Array (FPGA) implementation of the analysis and synthesis filter banks which are the fundamental components of multirate systems. The implementation utilizes the parallel form of the distributed arithmetic technique which enables maximum exploitation of the parallelism inherent in the multirate filtering operation. Performance results demonstrate the effectiveness of the implementation and suggest that the FPGA platform is indeed attractive for implementing multirate filter banks..

Multichannel Filter Banks and Their Implementation Using Computers with a Parallel Structure

The paper is devoted to the development of a WOLA-algorithm (weighted overlap add algorithm) for processing vector (multichannel) signals. The algorithm is considered as a generalization of one-dimensional WOLA with certain modifications. WOLA is expounded as an algorithm for real-time signal processing and the main advantages of WOLA are provided. We also discuss software-hardware implementation of WOLA using CPU (Central Processing Unit) and CUDA (Compute Unified Device Architecture). Finally we demonstrate the possibility of reducing hardware costs for multichannel signal processing using FPGA (field programmable gate arrays) and distributed arithmetic.

Integer low delay and MDCT filter banks

2002

Recently lifting-based integer approximations of filter banks have received much attention, especially in the field of image coding. This paper focuses on the application of these techniques to cosine modulated filter banks for audio coding, including not only the Modified Discrete Cosine Transform (MDCT) but also low delay filter banks. Applications of these integer filter banks include lossless audio coding and backward compatible lossless enhancement of MDCTbased perceptual audio coding schemes, such as MPEG-2/4 AAC.

Low Delay Filter Banks with Perfect Reconstruction

Frequenz, 1996

The design of modulated filter banks with a low system delay and with perfect reconstruction will be shown. The filter lengths K can be chosen arbitrarily. The well known orthogonal filter banks have a system delay of K-1 samples. The proposed filter banks can reduce this delay to N-1 samples, where N is the number of bands. The design method uses a decomposition or factorization of the polyphase matrix into cascades of simple matrices. Several factorizations with different properties will be shown. A factorization will be introduced which is more general and needs fewer multiplications than previous approaches (K/2 + N). The resulting filter banks can have analysis and synthesis frequency responses that can be made different from each other, leading to biorthogonal filter banks. An optimization algorithm for the frequency response of the resulting filter banks will be given. Examples show the feasibility of designing even big filter banks with many bands with low system delay and high stopband attenuation. Übersicht: Ein Verfahren zur Konstruktion von modulierten Filterbänken mit kurzer Verzögerungszeit und mit exakter Rekonstruktion wird vorgestellt. Die Filterlänge K kann beliebig gewählt werden. Im Fall der bekannten orthogonalen Filterbänke beträgt die Systemverzögerung K-l Abtastwerte. Die hier vorgeschlagenen Filterbänke können diese Verzögerungszeit auf N-\ Abtastwerte reduzieren, wobei N die Anzahl der Teilbänder ist. Das Verfahren zur Konstruktion der Filter basiert auf einer Zerlegung oder Faktorisierung der sogenannten Polyphasen-Matrix in Kaskaden einfacherer Matrizen. Mehrere Faktorisierungen mit unterschiedlichen Eigenschaften werden hergeleitet. Es wird eine Faktorisierung gezeigt, welche weniger Multiplikationen als frühere Ansätze benötigt (K/2 +N). Die resultierenden Filterbänke können Analyse-und Synthese-Frequenzgänge haben, die voneinander verschieden sind, sogenannten biorthogonale Filterbänke. Ein Optimierungs-Algorithmus für die Frequenzgänge der resultierenden Filterbänke wird vorgestellt. Beispiele zeigen, daß es möglich ist, l selbst große Filterbänke mit vielen Teilbandfiltern mit niedriger Systemverzögerung und hoher Sperrbereichs-Dämpfung zu konstruieren.

MINLAB: minimum noise structure for ladder-based biorthogonal filter banks

IEEE Transactions on Signal Processing, 2000

In this paper, we introduce a minimum noise structure for ladder-based biorthogonal (MINLAB) filter bank. The minimum noise structure ensures that the quantization error has a unity noise gain, even though the filter bank is biorthogonal. The coder has a very low design and implementation cost. Perfect reconstruction property is structurally preserved. Optimal bit allocation and coding gain formulas are derived. We show that the coding gain of the optimal MINLAB coder is always greater than or equal to unity. For both AR(1) process and MA(1) process, the MINLAB coder with two taps has a higher coding gain than the optimal orthonormal coder with an infinite number of taps. In addition to its superior decorrelation ability, it has many other desired features that make it a potentially valuable and attractive alternative to the orthonormal coder, especially for the high-fidelity compression.