A limited speech recognition system 2 Final report
Limited speech recognition system for computer voice link
Bobrow, D. G.↗
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A preliminary analysis technique for speech sound classification
Analysis method permitting English speech sound recognition by computer for different speakers
Niederjohn, R. J.↗
On multiple demand access satellite systems for speech communications in remote areas
Multiple access communication satellite systems providing reliable speech communication for low density use in remote areas
Hurd, W. J.↗
Organizing a special purpose computer using the FFT to perform speech analysis in real time
Design of special purpose computer using FFT to perform speech analysis in real time
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Real time statistical time series analyzer for speech segmentation
Real time statistical time series analyzer for speech segmentation
Stewart, C. H.↗
Speech therapy and voice recognition instrument
Characteristics of electronic circuit for examining variations in vocal excitation for diagnostic purposes and in speech recognition for determiniog voice patterns and pitch changes are described. Operation of the circuit is discussed and circuit diagram is provided.
Cohen, J.↗
Quantization noise in digital speech
The amount of quantization noise generated in a digital-to-analog converter is dependent on the number of bits or quantization levels used to digitize the analog signal in the analog-to-digital converter. The minimum number of quantization levels and the minimum sample rate were derived for a digital voice channel. A sample rate of 6000 samples per second and lowpass filters with a 3 db cutoff of 2400 Hz are required for 100 percent sentence intelligibility. Consonant sounds are the first speech components to be degraded by quantization noise. A compression amplifier can be used to increase the weighting of the consonant sound amplitudes in the analog-to-digital converter. An expansion network must be installed at the output of the digital-to-analog converter to restore the original weighting of the consonant sounds. This technique results in 100 percent sentence intelligibility for a sample rate of 5000 samples per second, eight quantization levels, and lowpass filters with a 3 db cutoff of 2000 Hz.
Schmidt, O. L.↗
A comparison of orthogonal transformations for digital speech processing.
Discrete forms of the Fourier, Hadamard, and Karhunen-Loeve transforms are examined for their capacity to reduce the bit rate necessary to transmit speech signals. To rate their effectiveness in accomplishing this goal the quantizing error (or noise) resulting for each transformation method at various bit rates is computed and compared with that for conventional companded PCM processing. Based on this comparison, it is found that Karhunen-Loeve provides a reduction in bit rate of 13.5 kbits/s, Fourier 10 kbits/s, and Hadamard 7.5 kbits/s as compared with the bit rate required for companded PCM. These bit-rate reductions are shown to be somewhat independent of the transmission bit rate.
Campanella, S. J.↗
Real-time speech analyzer
System uses phase-locked loops to give real-time information on speech spectrum by tracking the fundamental and its first 19 harmonics.
Hong, J. P.↗
Noise and Speech Interference: Proceedings of Minisymposium
Several papers are presented which deal with the psychophysical effects of interference with speech and listening activities by different forms of noise masking and filtering. Special attention was given to the annoyance such interruptions cause, particularly that due to aircraft flyover noises. Activities such as telephone listening and television watching were studied. A number of experimental investigations are described and the results are analyzed.
Shepherd, W. T.↗
A small inexpensive minicomputer system for speech research
A small but very effective minicomputer-based speech processing system costing just over 30,000 dollars is described here. The hardware and software comprising the system are discussed as well as immediate and future research applications.
Morris, C. F.↗
Required attention for synthesized speech perception for three levels of linguistic redundancy
The study evaluates the attention required for synthesized speech perception with reference to three levels of linguistic redundancy. Twelve commercial airline pilots were individually tested for 16 cockpit warning messages eight of which consisted of two monosyllabic key words and eight of which consisted of two polysyllabic key words. Three levels of linguistic redundancy were identified: monosyllabic words, polysyllabic words, and sentences. The experiment contained a message familiarization phase and a message recognition phase. It was found that: (1) when the messages are part of a previously learned and recently heard set, and the subject is familiar with the phrasing, the attention needed to recognize the message is not a function of the level of linguistic redundancy, and (2) there is a quantitative and qualitative difference between recognition and comprehension processes; only in the case of active comprehension does additional redundancy reduce attention requirements.
Simpson, C. A.↗
Index to NASA news releases and speeches, 1979
A listing of news releases distributed by the Office of Public Affairs, NASA Headquarters, and a selected listing of speeches given by members of the Headquarters staff during 1979 are presented.
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Index to NASA news releases and speeches, 1980
A listing is provided of 201 news releases distributed by the Office of Public Affairs, NASA Headquarters and 10 selected speeches presented by Headquarters staff in 1980. Subject and name indexes are arranged alphabetically. Indexes to titles, news release numbers and accession numbers are arranged numerically.
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Human factors issues associated with the use of speech technology in the cockpit
The human factors issues associated with the use of voice technology in the cockpit are summarized. The formulation of the LHX avionics suite is described and the allocation of tasks to voice in the cockpit is discussed. State-of-the-art speech recognition technology is reviewed. Finally, a questionnaire designed to tap pilot opinions concerning the allocation of tasks to voice input and output in the cockpit is presented. This questionnaire was designed to be administered to operational AH-1G Cobra gunship pilots. Half of the questionnaire deals specifically with the AH-1G cockpit and the types of tasks pilots would like to have performed by voice in this existing rotorcraft. The remaining portion of the questionnaire deals with an undefined rotorcraft of the future and is aimed at determining what types of tasks these pilots would like to have performed by voice technology if anything was possible, i.e. if there were no technological constraints.
Kersteen, Z. A.↗
Index to NASA news releases and speeches, 1983
A listing is presented of 271 news releases distributed by the Office of Public Affairs, NASA Headquarters and 72 selected speeches given by Headquarters staff in 1983. Subject and personal name indexes are arranged alphabetically. Indexes to titles, news release numbers, and accession numbers are arranged numerically.
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Application of a VLSI vector quantization processor to real-time speech coding
Attention is given to a working vector quantization processor for speech coding that is based on a first-generation VLSI chip which efficiently performs the pattern-matching operation needed for the codebook search process (CPS). Using this chip, the CPS architecture has been successfully incorporated into a compact, single-board Vector PCM implementation operating at 7-18 kbits/sec. A real time Adaptive Vector Predictive Coder system using the CPS has also been implemented.
Davidson, G.↗
Visual Speech-Training Aid for the Deaf
Teaching deaf to speak aided by electronic system provides striking colored, pictorial representation of sound; energy at different frequencies as function of time. Other modalities, such as nasality, intra-oral pressure, and lip-muscle contraction, pictorialized simultaneously. Use of standard components, including personal microcomputer, helps reduce cost below prior voice-training systems. Speech-training system, microphone output separated by filters into narrow frequency bands, changed into digital signals, formatted by computer, and displayed on television screen. Output from other sensors displayed simultaneously or screen split to allow sound produced by student to be compared with that of teacher.
Miller, Robert J.↗