linear prediction is formulated in a vector space by means of the orthogonal transformation, with which the L(1) criterion can be easily incorporated to yield an efficient iterative algorithm. An improvement over the ...
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linear prediction is formulated in a vector space by means of the orthogonal transformation, with which the L(1) criterion can be easily incorporated to yield an efficient iterative algorithm. An improvement over the covariance method is verified in the experiments with a high-pitch synthetic vowel.
A low-complexity speech recognition method applicable to digital communication networks is proposed. A feature set suitable for speech recognition is obtained from quantised LSP parameters in CELP-type coders without ...
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A low-complexity speech recognition method applicable to digital communication networks is proposed. A feature set suitable for speech recognition is obtained from quantised LSP parameters in CELP-type coders without reconstructing the speech signals. The authors present the effects of the speech coder on speaker-independent recognition performance. and show that the recognition accuracy of the proposed method is better than that of the recogniser using reconstructed speech signals.
In signal coherent detection, data-aided (DA) method has high detection accuracy, but unavoidably suffers from a large processing delay. Meanwhile, a decision-directed (DD) method incurs no processing delay, but suffe...
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In signal coherent detection, data-aided (DA) method has high detection accuracy, but unavoidably suffers from a large processing delay. Meanwhile, a decision-directed (DD) method incurs no processing delay, but suffers from error propagation problem. Motivated by the above problems of DA and DD methods, the authors present a novel signal detection algorithm for delay-sensitive applications employing orthogonal frequency-division multiplexing systems. The proposed detection method provides similar detection accuracy to the DA method and incurs no processing delay. This method employs channel estimation followed by linear prediction and interpolation to obtain the channel-state information for symbol detection. To achieve a better prediction performance, they perform the linear prediction on the channel taps in the time domain, and conduct the interpolation using a raised cosine filter. Simulations on physical channel models verify the improvements of the proposed method.
Rate-distortion theory provides the motivation for using data compression techniques on matrices of N LPC vectors. This leads to a simple extension of speech coding techniques using vector quantization. The effects of...
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Rate-distortion theory provides the motivation for using data compression techniques on matrices of N LPC vectors. This leads to a simple extension of speech coding techniques using vector quantization. The effects of using the generalized Lloyd algorithm on such matrices using a summed Itakura-Saito distortion measure are studied, and an extension of the centroid computation used in vector quantization is presented. The matrix quantizers so obtained offer substantial reductions in bit rates relative to full-search vector quantizers. Bit rates as low as 150 bits/s for the LPC matrix information (inclusive of gain, but without pitch and voicing) have been achieved for a single speaker, having average test sequence and codebook distortions comparable to those in the equivalent full-search vector quantizer operating at 350 bits/s. Preliminary results indicate that higher quality or lower bit rates may be achieved with enough computational resources.
For original paper, see D.P. Palomar et al., ibid., vol. 35, no. 13, pp. 1058-9 (1999). Palomar et al. addressed the question of LPC filter re-optimisation and proposed a recursive algorithm that they considered promi...
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For original paper, see D.P. Palomar et al., ibid., vol. 35, no. 13, pp. 1058-9 (1999). Palomar et al. addressed the question of LPC filter re-optimisation and proposed a recursive algorithm that they considered promising. The present commentator shows that the iterative algorithm employed by Palomar is unnecessarily complex because of poor initialisation. The algorithm that uses available speech data at the very first step is shown to perform well. The results of the one-shot algorithm can be used to initiate Paolmar's method to significantly reduce the number of iterations
A hybrid fiber coaxial (HFC) network uses both optical fibers and coaxial cables for cable TV networks. Coaxial cables are mainly used for access networks. Recently, fiber to the home (FTTH) is being widely deployed. ...
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A hybrid fiber coaxial (HFC) network uses both optical fibers and coaxial cables for cable TV networks. Coaxial cables are mainly used for access networks. Recently, fiber to the home (FTTH) is being widely deployed. For cable TV companies to utilize readily deployed FTTH, legacy coax network-based customer premise equipment (CPE) such as cable modems and set top boxes may have to be replaced with fiber network based CPE. In order to reduce the expenditure incurred in this process, radio over Internet Protocol (RoIP) technology has been proposed. In the RoIP system, RF signal for coax generated by legacy CPE toward the headend is first sampled, and digitized, and then encapsulated in IP packets, which are then sent to the headend using FTTH access technologies such as passive optical network (PON). In the process of digitizing RF signal, a huge amount of data much more than the base band data is generated. So, a data compression method is required to lower the upstream bit rate maintaining the signal quality. Most compression methods are significantly degraded due to the interference caused by burst noise in the upstream link. Therefore, this paper proposes a new compression method which combines linear predictive coding (LPC), block scaling and non-linear quantization for CATV upstream links. The proposed method is demonstrated to greatly reduce the impact of burst noise while maintaining the compression performance.
Techniques for the quantitative assessment and classification of vocal disorders are described. Models for vocal disorders using speech synthesis are examined. Methods for characterizing the electroglottography (EGG) ...
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Techniques for the quantitative assessment and classification of vocal disorders are described. Models for vocal disorders using speech synthesis are examined. Methods for characterizing the electroglottography (EGG) waveform and the assessment of vocal quality using acoustic and EGG signal features are discussed.< >
G.729 is a CS-ACELP-based [1] standard for 8kbit/s speech compression and is defined by the ITU. In the G.729 encoding phase. the open-loop pitch T-op is estimated for each frame to reduce the computation required to ...
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G.729 is a CS-ACELP-based [1] standard for 8kbit/s speech compression and is defined by the ITU. In the G.729 encoding phase. the open-loop pitch T-op is estimated for each frame to reduce the computation required to search for the best adaptive codebook delay. However, > 25% CPU time is required for the open-loop pitch analysis. The weighted delta-LSP(WD-LSP) function is employed here to reduce the computation required for open-loop pitch analysis. An 81% saving is made in the computation of T-op. A total computational saving of 21% for the encoding phase Is achieved and the speech quality still sounds good (MOS = 3.5).
In this letter, we demonstrate that the commonly assumed:Arrhenius law is inconsistent with extrapolation of data-retention time-to-failure of nonvolatile memories in highly accelerated life-tests. We argue that the r...
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In this letter, we demonstrate that the commonly assumed:Arrhenius law is inconsistent with extrapolation of data-retention time-to-failure of nonvolatile memories in highly accelerated life-tests. We argue that the retention time, namely log(t(R)), varies linearly with temperature T rather than with 1/T as commonly assumed, yielding an important reduction in the extrapolated time-to-failure. Extensive experimental results demonstrate the physical consistency of the new model. In particular, data-retention of EPROM devices and leakage current of interpoly dielectric and gate oxide have been investigated over a wide range of temperatures. Finally, it is shown that our model reconciles seemingly controversial activation energy data from the literature.
Line spectrum pairs (LSPs) are the roots (located in the complex-frequency or z-plane) of symmetric and antisymmetric polynomials synthesized using a linear prediction (LPC) polynomial. The angles of these roots, know...
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Line spectrum pairs (LSPs) are the roots (located in the complex-frequency or z-plane) of symmetric and antisymmetric polynomials synthesized using a linear prediction (LPC) polynomial. The angles of these roots, known as line-spectral frequencies (LSFs), implicitly represent the LPC polynomial and hence the spectral envelope of the underlying signal. BY exploiting the duality between the time and frequency domains, we define analogous polynomials in the complex-time variable zeta. The angles of the roots of these polynomials in zeta -plane now correspond to zero-crossing time instants. Analogous to the fact that the line-spectral frequencies represent the spectral envelope of a signal, these zero-crossing locations can be used to represent the temporal envelope of bandpass signals.
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