a new method for coding generic audio signals at 64 kbit/s in the bandwidth 20-15000 Hz with a low delay is presented. It combines sub-band coding, low delay CELP algorithm and cascaded filterbanks. We show how the di...
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a new method for coding generic audio signals at 64 kbit/s in the bandwidth 20-15000 Hz with a low delay is presented. It combines sub-band coding, low delay CELP algorithm and cascaded filterbanks. We show how the different parameters of LD-CELP can be adapted to achieve a better quality, perceptual coding techniques are integrated into the encoder for allocating bits to each sub-band.
Multiple pulse excited linear predictive coding (MPLPC) has recently received a great deal of attention in the literature as an attractive means of speech coding at data rates below 10 Kbits/second. The existing appro...
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Multiple pulse excited linear predictive coding (MPLPC) has recently received a great deal of attention in the literature as an attractive means of speech coding at data rates below 10 Kbits/second. The existing approaches to MPLPC analysis arrive at the parameters for an all-pole model by minimizing the mean squared modeling error before attempting to find a set of pulses to excite the model. The strategy proposed here selects the all-pole parameters to concentrate the model excitation in a finite number of locations. The goal is then to produce a maximally pulse-like residual as a result of the all-pole parameter estimation.
An end-point detector for LPC speech using squared prediction error look-ahead and automatic/manual threshold determination is described. The detector is algorithmically simple, computationally efficient,and uses only...
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An end-point detector for LPC speech using squared prediction error look-ahead and automatic/manual threshold determination is described. The detector is algorithmically simple, computationally efficient,and uses only one decision parameter. Preliminary tests indicate that it is relatively immune to transient pulses and various low-level noises, yet preserves low-level speech sounds such as weak fricatives to a significant extent under moderate noise conditions. Tests indicate that 93.8% of automatically determined endpoints agree to within two frames of manually determined endpoints. The detector is especially suitable for use in vector-quantization based LPC systems, where the squared prediction error is easily available.
Fully depleted (FD) SOI CMOS is a contender for low-voltage IC applications. However, as FD/SOI MOSFETs are scaled, floating-body effects, which previously seemed insignificant, become important. In this paper, we rep...
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Fully depleted (FD) SOI CMOS is a contender for low-voltage IC applications. However, as FD/SOI MOSFETs are scaled, floating-body effects, which previously seemed insignificant, become important. In this paper, we report kinks in the measured subthreshold current-voltage characteristics of highly scaled FD/SOI MOSFETs, and we describe and model the underlying physical mechanism, showing how it differs from the familiar kink effect in partially depleted (PD) devices. The insight afforded qualifies the meaning of FD/SOI and implies new design issues for low-voltage SOI CMOS.
The paper describes the software architecture of an Italian text-to-speech synthesis system based on the joining of LPC coded diphones. The automatic voice response system is designed according to multichannel and rea...
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The paper describes the software architecture of an Italian text-to-speech synthesis system based on the joining of LPC coded diphones. The automatic voice response system is designed according to multichannel and real time criteria. For each output channel, the following operations are performed: pre-processing of the input string of characters, translation into the proper sequence of diphones, generation of prosodic contours and real-time control of a hardware speech synthesizer.
In the context of signal reconstruction and coding, a new robust parametric formulation to linear predictive coding (LPC) is introduced. The linear prediction filter coefficients are transformed into a set of weighted...
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In the context of signal reconstruction and coding, a new robust parametric formulation to linear predictive coding (LPC) is introduced. The linear prediction filter coefficients are transformed into a set of weighted line frequencies. The positive weights play the dual role of a new set of parameters and simultaneously they exhibit the relative importance of the associated line frequencies. This new representation for LPC is shown to be always stable under quantization.
linear Prediction (LP) and the well known fast algorithms of the Levinson type have already widely proven their efficiency in various fields. But these algorithms fail to be applicable when one of the principal minors...
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linear Prediction (LP) and the well known fast algorithms of the Levinson type have already widely proven their efficiency in various fields. But these algorithms fail to be applicable when one of the principal minors of the signal covariance matrix happens to be singular (or close to singularity). This paper investigates this singular case both for scalar and vector (multichannel) time series. It is shown that the standard lattice may be replaced by a convenient lossless lattice. Various techniques are proposed to leap over the singular case. They are analysed in terms of generalized choleski factors. The paper then deals with the multichannel case which is attached by a reduction of redundant outputs leading back to the scalar singular case. The results are applicable to the design of robust LPC algorithms and to the use of ARMA models in antenna array processing.
Line spectrum pairs (LSP) representation of linear predictive coding coefficients is widely used in speech coding, speech recognition and other domains due to its desirable interpolation and quantization properties. S...
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Line spectrum pairs (LSP) representation of linear predictive coding coefficients is widely used in speech coding, speech recognition and other domains due to its desirable interpolation and quantization properties. Several methods proposed for calculating LSP parameters have been complicated by high computation complexity. This paper proposed an effective and efficient algorithm APF using Aitken iterative method and polynomial synthesis division. LSP parameters were estimated by obtaining a root of N-order nonlinear equation by Aitken iterative method at first, then decreasing degrees with polynomial synthesis division, and finally calculating quartic equation using Ferrari's solution. Theoretic analysis and experiment results show that the proposed algorithm has not only high precision but also low calculation complexity
Although powerful device simulators are being developed, analytical models are still essential for depicting the underlying physical mechanisms. Recently, attention was paid to a "unified" approach able to a...
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Although powerful device simulators are being developed, analytical models are still essential for depicting the underlying physical mechanisms. Recently, attention was paid to a "unified" approach able to account for MOSFET continuous operation from weak to moderate and strong inversion. In this paper, we propose an original model which applies not only to bulk Si and partially depleted SOI MOSFET's, but also to ultrathin film SOI transistors.< >
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