VLSI Implementation of an Adaptive Noise Canceller

Adaptive Noise cancelling is a speech-specific filtering technique to suppress additive interference. It is a sensible choice for speech-orientated devices in situations where the designer has no knowledge of the properties of interference that could potentially corrupt the input speech to a point beyond intelligibility. A good example of devices subject to such noise is mobile telephones, where the user may be communicating in a variety of environments. However, constraints appear when implementing a noise-cancelling algorithm on such a portable device, and issues of power consumption and silicon area become prominent. This paper discusses an adaptive noise cancelling scheme and presents a VLSI implementation strategy. It then considers some of the benefits of the implementation and its potential area for improvement

An Explicit Criterion for Adaptive Periodic Noise Canceller Robustness Applied to Feedback Cancellation

This paper addresses the issue of robustness of an LMS-driven Adaptive Periodic Noise Canceller (APNC) in a closed-loop system. By adopting an analysis based on H-infinity theory, expressions are given under which the APNC, driven by the LMS algorithm, will exhibit robust performance properties. Simulation results are used to verify the analysis. Comparison is also made with an expression for stepsize derived for the less stringent bound of algorithm stability to demonstrate the strictness of the robustness criterion

A Hardware Optimised CMOS Adaptive Noise Canceller Implementation

Up until now, the main foci of development in mobile communication equipment have been to decrease its size and to extend its battery operation times. However, further reductions in the size of devices are physically limited by the user interface requirements and therefore, alternative aspects of these devices must be targeted for enhancement by designers. A feature of mobile communications equipment is the variety of environments within which they are used, so algorithms that can improve the quality of a transmission are highly desirable. In this paper, mobile telephony devices are being specifically considered and a CMOS implementation of the filter block of an adaptive noise canceller will be presented. Results will then be given to demonstrate how this circuit can significantly increase speech quality by suppressing interfering noise without requiring any prior assumptions on its properties

Timbral attributes for objective quality assessment of the Irish Tin Whistle

In this paper we extract various timbral attributes for a variety of Irish tin whistles, and use these attributes to form an objective quality assessment of the instruments. This assessment is compared with the subjective experiences of a number of professional musicians. The timbral attributes are drawn from those developed in the Timbre Mode

Application of Real-time AMDF Pitch Detection in a Voice Gender Normalisation System

Traditionally the interest in voice gender conversion was of a more theoretical nature rather than founded in real-life applications. However, with the increase in mobile communication and the resulting limitation in transmission bandwidth new approaches to minimising data rates have to be developed. Here voice gender normalisation (VGN) presents an efficient method of achieving higher compression rates by using the VGN algorithm to remove gender specific components of a speech signal and thus enhancing the information content to be transmitted. A second application for VGN is in the field of speech controlled systems, where current speech recognition algorithms have to deal with the voice characteristics of a speaker as well as the information content. Here again the use of VGN can remove the speaker's voice gender characteristics and thus enhance the message contents. Therefore, such a system would be capable of achieving higher recognition rates while being independent of the speaker. This paper presents the theory of a VGN system and furthermore, outlines an efficient real-time hardware implementation for the use in portable communications equipment

A Hardware Optimised CMOS Adaptive Noise Canceller Implementation

Up until now, the main foci of development in mobile communication equipment have been to decrease its size and to extend its battery operation times. However, further reductions in the size of devices are physically limited by the user interface requirements and therefore, alternative aspects of these devices must be targeted for enhancement by designers. A feature of mobile communications equipment is the variety of environments within which they are used, so algorithms that can improve the quality of a transmission are highly desirable. In this paper, mobile telephony devices are being specifically considered and a CMOS implementation of the filter block of an adaptive noise canceller will be presented. Results will then be given to demonstrate how this circuit can significantly increase speech quality by suppressing interfering noise without requiring any prior assumptions on its properties

VLSI Implementation of an Adaptive Noise Canceller

Adaptive Noise cancelling is a speech-specific filtering technique to suppress additive interference. It is a sensible choice for speech-orientated devices in situations where the designer has no knowledge of the properties of interference that could potentially corrupt the input speech to a point beyond intelligibility. A good example of devices subject to such noise is mobile telephones, where the user may be communicating in a variety of environments. However, constraints appear when implementing a noise-cancelling algorithm on such a portable device, and issues of power consumption and silicon area become prominent. This paper discusses an adaptive noise cancelling scheme and presents a VLSI implementation strategy. It then considers some of the benefits of the implementation and its potential area for improvement

An Explicit Criterion for Adaptive Periodic Noise Canceller Robustness Applied to Feedback Cancellation

This paper addresses the issue of robustness of an LMS-driven Adaptive Periodic Noise Canceller (APNC) in a closed-loop system. By adopting an analysis based on H-infinity theory, expressions are given under which the APNC, driven by the LMS algorithm, will exhibit robust performance properties. Simulation results are used to verify the analysis. Comparison is also made with an expression for stepsize derived for the less stringent bound of algorithm stability to demonstrate the strictness of the robustness criterion

Implementation of real-time AMDF pitch-detection for voice gender normalisation

Traditionally the interest in voice gender conversion was of a more theoretical nature rather than founded in real-life applications. However, with the increase in mobile communication and the resulting limitation in transmission bandwidth new approaches to minimising data rates have to be developed. Here voice gender normalisation (VGN) presents a novel method of achieving higher compression rates by using the VGN algorithm to remove all gender specific components of a speech signal and thus leaving only the information content to be transmitted. A second application for VGN is in the field of speech controlled systems, where current speech recognition algorithms have to deal with the voice characteristics of a speaker as well as the information content. Here again the use of VGN can remove the speakers voice characteristics leaving only the pure information. Therefore, such a system would be capable of achieving much higher recognition rates while being independent of the speaker. This paper presents the theory of a gender removal system based on VGN and furthermore, outlines an efficient real-time hardware implementation for use in portable communications equipment