Download Alternative analysis-resynthesis approaches for timescale, frequency and other transformations of musical signals
This article presents new spectral analysis-synthesis approaches to musical signal transformation. The analysis methods presented here involve the use of a superior quality technique of frequency estimation, the Instantaneous Frequency Distribution (IFD), and partial tracking. We discuss the theory behind the IFD, comparing it to other existing methods. The partial tracking analysis employed in this process is explained fully. This is followed by a look into the three resynthesis methods proposed by this work, based on different approaches to additive synthesis. A number of transformations of musical signals are proposed to take advantage of the analysis-synthesis techniques. Performance details and specific aspects of this implementation are discussed. This is complemented by a look at some of the results of these methods in the time-stretching of audio signals, where they will be shown to perform better than many of the currently available techniques.
Download CMOS Implementation of an Adaptive Noise Canceller into a Subband Filter
In recent years the demand for mobile communication has increased rapidly. While in the early years of mobile phones battery life was one of the main concerns for developers speech quality is now becoming one of the most important factors in the development of the next generation of mobile phones. This paper describes the CMOS implementation of an adaptive noise canceller (ANC) into a subband filter. The ANC-Subband filter is able to reduce noise components of real speech without prior knowledge of the noise properties. It is predestined to be used in mobile devices and therefore, uses a very low clock frequency resulting in a small power consumption. This low power consumption combined with its small physical size enables the circuit also be used in hearing aids to efficiently reduce noise contained in the speech signal.
Download Comparing synthetic and real templates for dynamic time warping to locate partial envelope features
In this paper we compare the performance of a number of different templates for the purposes of split point identification of various clarinet envelopes. These templates were generated with AttackDecay-Sustain-Release (ADSR) descriptions commonly used in musical synthesis, along with a set of real templates obtained using k-means clustering of manually prepared test data. The goodness of fit of the templates to the data was evaluated using the Dynamic Time Warping (DTW) cost function, and by evaluating the square of the distance of the identified split points to the manually identified split points in the test data. It was found that the best templates for split point identification were the synthetic templates followed by the real templates having a sharp attack and release characteristic, as is characteristic of the clarinet envelope.