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Publications

Publications by CTM

2005

Run-Time Reconfiguration Support for FPGAs with Embedded CPUs: The Hardware Layer

Authors
Ferreira, JC; Silva, MM;

Publication
19th International Parallel and Distributed Processing Symposium (IPDPS 2005), CD-ROM / Abstracts Proceedings, 4-8 April 2005, Denver, CO, USA

Abstract
We report on work in progress that aims to provide a run-time management kernel for applications running on FPGAs with embedded CPUs. We describe the global concept, the organization of the hardware environment for the reconfigurable modules and the reconfiguration strategy supported by the run-time management kernel. Practical issues concerning the implementation of the system on a Virtex-II Pro-based board are also addressed.

2005

Using a tightly-coupled pipeline in dynamically reconfigurable platform FPGAs

Authors
Silva, ML; Ferreira, JC;

Publication
DSD 2005: 8th Euromicro Conference on Digital System Design, Proceedings

Abstract
The paper describes the organization and use of a pipeline that is tightly-coupled to the CPU inside a platform FPGA with support for dynamic partial reconfiguration. It describes the overall hardware system organization and the pipeline structure, and presents the associated development environment and run-time support system, including the support for dynamically changing pipeline implementations and altering the operations of a pipeline stage.

2005

Accurate and robust frequency estimation in the ODFT domain

Authors
Ferreira, A; Sinha, D;

Publication
2005 WORKSHOP ON APPLICATIONS OF SIGNAL PROCESSING TO AUDIO AND ACOUSTICS (WASPAA)

Abstract
This paper presents new results improving by a factor of 10 the accuracy of an Odd-DFT based frequency estimation algorithm. These results are shown to be robust to the influence of additive noise and compare favorably to other non-iterative frequency domain estimation algorithms. A perspective is given oil possible application areas, namely those involving real-time constraints.

2005

An improved adaptive room equalization in the frequency domain

Authors
Leite, A; Ferreira, AJS;

Publication
Audio Engineering Society - 118th Convention Spring Preprints 2005

Abstract
This paper presents several improvements that have been introduced to the design and operation of an adaptive 20-band room equalizer. The equalizer is implemented on a TMS320C6711 DSP platform and performs fast FIR filtering in the frequency domain. In order to reach fast adaptation to time-varying acoustic conditions, several adaptation rules operating in the frequency domain have been evaluated and the impact of a frequency-varying stepsize parameter on the convergence rate has been studied. These results will be presented along with ideas and plans for future developments.

2005

A Fractal Self-Similarity Model for the spectral representation of audio signals

Authors
Sinha, D; Ferreira, AJS; Sen, D;

Publication
Audio Engineering Society - 118th Convention Spring Preprints 2005

Abstract
In the application of conventional audio compression algorithms to low bit rate audio coding one is faced with the unsatisfactory tradeoff between coarser quantization and audio bandwidth reduction. Frequency Extension has therefore emerged as an important tool for the satisfactory performance of low bit rate audio codecs. In this paper we describe one of a newer class of Frequency Extension techniques which are applied directly to the high frequency resolution representation of the signal (e.g., MDCT). This particular technique is based on a Fractal Self-Similarity Model (FSSM) for the short-term frequency representation of the signal. The FSSM model, which may include multiple dilation and translation terms, has been found to be effective for a wide variety of speech and music signals and provides a compact description for long term correlation that may exist in frequency domain. The high frequency resolution of MDCT aids in accurate parameter estimation for the model, which in turn has shown promise as a Frequency Extension tool that offers a detailed and natural sounding quality at low bit rates. Structure of the FSSM model, issues related to parameter estimation, and its application to audio coding for bit rates of 8-48 kbps is discussed. Audio demos are available at http://www.atc-labs.com/fssm.

2005

An accurate method of detection and cancellation of multiple acoustic feedbacks

Authors
Rocha, AF; Ferreira, AJS;

Publication
Audio Engineering Society - 118th Convention Spring Preprints 2005

Abstract
This paper presents a new method to the adaptive cancellation of acoustic feedbacks. The method uses high resolution frequency analysis and high-Q notch filters so as to accurately detect feedbacks and cancel them without disturbing noticeably the main audio spectrum. The method will be described, its implementation on a TMS320C6711 DSP platform for real time operation will be explained, and results for the adaptive cancellation of two simultaneous acoustic feedbacks will be presented.

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