Showing papers on "Voice activity detection published in 1970"

Speech synthesis by concatenation of formant encoded words

Abstract: Audio response units that select speech sounds, stored in analog or coded digital form, as the excitation for a speech synthesizer are widely used, for example in telephone audio announcement terminals. The speech produced by most units is noticeably artifical and mechanical sounding.

Parameter estimation in speech: A lesson in unorthodoxy

Abstract: The accurate estimation of both discrete and continuous parameters of speech signals has played a central role in speech processing and research. Interestingly, the most successful estimation procedures have often relied on intuition based on knowledge of speech signals and their production in the human vocal apparatus rather than routine applications of well-established theoretical methods. This experience in speech processing should serve as a reminder that a thorough understanding of the signal is paramount for successful analyses of real-world processes.

Normalization and adaptation of speech data for automatic speech recognition

Abstract: Methods of normalizing and adapting speech data, in the amplitude, frequency and time domains, are described and discussed. Means of automatic gain control and automatic spectrum normalization have been implemented. The problem of adjusting phoneme boundaries is considered, together with the need for normalization in the time domain. Results obtained for the recognition of the digits by a wide range of speakers are given.

Sequential feature extraction for waveform recognition

Abstract: Many practical waveform recognition problems involve a sequential structure in time. One obvious example is speech. The information in speech can be assumed to be transmitted sequentially through a phonetic structure. Other examples are seismograms, radar signals, or television signals. We will take advantage of this sequential structure to develop a means of feature extraction and recognition for waveforms. The results will be applied to speech recognition.

Speech and vocoders

Abstract: Speech signals are produced by relatively slow articulatory movements. This suggests that the information rate of the speech signal is much less than would be expected by considering the bandwidth of the acoustic signal. Vocoders attempt to exploit the redundancy in the speech waveform by extracting and transmitting the information bearing parameters of the speech signal. At the receiver, these parameters are used to control a speech synthesizer that reproduces the original signal without any serious loss of intelligibility but with some degradation of quality. The paper describes speech production principles, and their application to speech synthesis; the operation of various types of vocoder and the problems of pitch extraction.

The Re-Coding of Speech

Abstract: Modern electronic techniques of analysis and synthesis allow speech to be processed in real time for a variety of applications. Various types of voice coder (vocoder) have been developed: the basic aim of these is more efficient communications, but they may also be applied to studies of speech by controlled alteration of its acoustic parameters—‘re-coding’ the speech signal.One application of recoding is in the correction of speech from deep-sea divers breathing a helium/oxygen atmosphere. The increased speed of sound alters the acoustic code of their speech and destroys intelligibility: a modified vocoder has been developed to recode this helium speech and restore communication. A similar technique may be used to increase the speed of normal speech.Speech recoding has potential applications in assisting the severely deaf who have usable hearing at low frequencies only, where the information content of normal speech is minimal. Various attempts have been made to improve their communication by recoding spe...