The United States government has developed a new Federal Standard 2400 bps vocoding algorithm called MELP Mixed Excitation Linear Prediction [1]. This vocoder has very acceptable voice quality under benign error-free channel conditions. However, when subjected to high error conditions as could be experienced in tactical vehicular operations, amelioration techniques may be employed which take ad...

—The performance of convolutional codes decoding by the Viterbi algorithm should not depend on the particular distribution of zeros and ones in the input messages, as they are linear. However, it was identified that specific implementations of Add-Compare-Select unit for the Viterbi Algorithm demonstrate the decoding performance that depends on proportion of elements in the input message. It is...

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This work designs sequence detectors for channels with intersymbol interference (ISI) and correlated (and/or signal-dependent) noise. We describe three major contributions. i) First, by modeling the noise as a finite-order Markov process, we derive the optimal maximum-likelihood sequence detector (MLSD) and the optimal maximum a posteriori (MAP) sequence detector, extending to the correlated no...

In a hidden Markov model, the underlying Markov chain is usually hidden. Often, the maximum likelihood alignment (Viterbi alignment) is used as its estimate. Although having the biggest likelihood, the Viterbi alignment can behave very untypically by passing states that are at most unexpected. To avoid such situations, the Viterbi alignment can be modified by forcing it not to pass these states...

This paper presents an initial study to perform Iarge-vocabuIary continuous Mandarin speech recognition based on a Segmental Probability Model(SPM) approach. SPM was first proposed for recognition of isolated Mandarin syllables, in which every syllable must be equally segmented before recognition. Therefore, A concatenated syllable matching algorithm in place of the conventional Viterbi search ...

Error correction is an integral part of any communication system and for this purpose, the convolution codes are widely used as forward error correction codes. For decoding of convolution codes, at the receiver end Viterbi Decoder is being employed. The parameters of Viterbi algorithm can be changed to suit a specific application. The high speed and small area are two important design parameter...

The Viterbi algorithm is the maximum likelihood algorithm that is used for the decoding of convolutional codes. In order to determine the survivor path in a trellis, it is necessary to calculate the metrics of each branch. In this paper, we propose a method that reduces the number of branches in the trellis and consequently its complexity, based on the reliability of the received signal samples...