Saturday, August 12, 2006

Digital Broadcasters|AES Seoul Papers (9)

The 29th AES Conference, "Audio for Mobile and Handheld Devices", all digital, September 2 to 4, 2006 Seoul National, lUniversity Campus

Digital Audio Presentations - Part 9

A Band Extension Technique for Digital G.711 Speech Based on Full Wave Rectification and Steganography

Invited Speaker:

Naofumi Aoki, Hokkaido University, Japan

This study investigates a digital band extension technique for speech data encoded with G.711, the most common codec for digital speech communications systems such as VoIP. The proposed technique employs steganography for the transmission of the side information required for the digital band extension based on full wave rectification. Due to the steganography, the proposed technique is able to enhance the speech quality without an increase of the amount of data transmission. From the results of a subjective evaluation, it is indicated that the proposed technique may potentially be useful for improving digital speech quality, compared with the conventional.

Adaptive Microphone Array with Self-Delay Estimator

Invited Speakers:

Yang-Won Jung, Hyo Jin Kim and Seung Jong Choi, LG Electronics, Korea,

Hong-Goo Kang, Yonsei University, Korea

In real environments, it is difficult to acquire clean speech because of the noise and the reverberation in the environments. Microphone array system is the one of the most promising solution which can provide accurate acquisition of speech in noisy environments. Normally, a time delay estimator is required for an adaptive microphone array system. In this paper, an adaptive microphone array system with self-delay estimator is proposed. The generalized sidelobe canceller (GSC) with an adaptive blocking matrix (ABM) is considered as an adaptive array algorithm. By showing that the ABM can estimate the relative time delay between each sensor, the proposed system utilizes the ABM not only for blocking target components in the blocked digital signal path, but also for estimating the relative time delay. Therefore, the proposed system requires only the GSC structure while maintaining the system performance similar to the conventional system using an additional time delay estimator as a preprocessor. Simulation results show that the performance of the proposed digital system is identical to the conventional system that uses an additional time delay estimation module.

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