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Showing papers on "Spectrogram published in 1975"


Patent
18 Nov 1975
TL;DR: In this article, a visual display device such as a scan converter and video monitor is provided which receives, in short time segments, signals from a time compression heterodyne type spectrum analyzer and displays these segments on a raster.
Abstract: Apparatus which provides a real time sound spectrogram of signals such as speech which are complex in their frequency content and also vary rapidly in time, is described. A visual display device such as a scan converter and video monitor is provided which receives, in short time segments, signals from a time compression heterodyne type spectrum analyzer and displays these segments on a raster. Display control circuits generate a vertical sweep signal and fast and slow horizontal sweep signals in synchronism with the short time segments. Successive spectrums are plotted and displayed under the control of the fast horizontal sweep and the vertical sweep while the spectrogram, as of an entire speech utterance, is made up of successive spectrums during the interval of the slow horizontal sweep. Thus a sound spectrogram of each short time interval is produced; there being only a short delay after utterance of the sound before the result appears on the display. The intensity of each frequency in the spectrum during each time segment and over each spectrum (viz., each piece of the spectrogram) is plotted in real time as the speech utterance is produced. The pieces are concatenated such that the perceptual effect is that of a continuous sound spectrogram which unfolds in real time. The frequency-time-intensity plot thus contains fine detail enabling the viewer to observe the characteristics of the speech utterance of interest such that the apparatus is especially suitable for use in speech training as to deaf students.

22 citations


Proceedings Article
03 Sep 1975
TL;DR: A speech understanding system with learning capabilities is presented and spoken senience is represented concisely by a description that can be used to reconstruct the sentence and to verify whether its meaning was not degraded by the coding.
Abstract: A speech understanding system with learning capabilities is presented. Its relevant aspecis are: a) The spoken senience is represented concisely by a description that can be used to reconstruct the sentence and to verify whether its meaning was not degraded by the coding. b) Syllables or broader coarticulation segments are the smallest units. c) The evaluation of an hypothesis is based on the probability that a syllable. a word or the sentence can generate the spectrogram of the spoken message and that a syntactic structure can generate its witch contour. d) Coarticulation effects are described in terms of pattern grammers, generating all the possible formant irajectories for a given utterence. e) Spectral and prosodic features can be learned by inference of stochastic finite-state-automats. f) More formant choices are allowed for a single syllable segment and an algorithm is proved for assigning to each choice a probability.

17 citations


Journal ArticleDOI
TL;DR: The optical technique used in the speech spectrogram generator described here permits the analysis of signals having frequency components within the ultrasonic or very-low-frequency ranges, and the system is capable of examining large amounts of data continuously throughout the processing.
Abstract: The optical technique used in the speech spectrogram generator described here permits the analysis of signals having frequency components within the ultrasonic or very-low-frequency ranges, and the system is capable of examining large amounts of data continuously throughout the processing.

9 citations


Journal ArticleDOI
L. Morris1
TL;DR: Techniques which enable fast reduction and display of multiintensity speech spectrograms on low-cost minicomputer systems are described.
Abstract: Interactive graphics processors have recently been included as standard components of several low-cost minicomputer systems. We describe techniques which enable fast reduction and display of multiintensity speech spectrograms on such systems.

5 citations



Journal ArticleDOI
TL;DR: An experiment is reported in which an interactive research tool—a Digital Pattern Playback (DPP)—is being used to evaluate a spectrum‐matching and dictionary‐search technique for speech recognition.
Abstract: Facilities which make spectrograms immediately available for visual comparison, easy modification of spectral data, and resynthesis of speech have proved to be particularly useful tools in speech research. This paper reports an experiment in which such an interactive research tool—a Digital Pattern Playback (DPP)—is being used to evaluate a spectrum‐matching and dictionary‐search technique for speech recognition. The DPP is a computer‐supported analysis‐synthesis facility which, in the present experiment, displays spectrograms of “unknown” sentences so that an analyst can list the important acoustic features of marked segments of the unknown sentence. Interrogation of a feature‐based dictionary then recovers all items with features which match the unknown segment. If necessary, additional features may be assigned to narrow the search. The reference spectrograms retrieved from the dictionary are compared, one at a time, with the spectrogram of the unknown sentence and the best match is selected for each un...

2 citations


Journal ArticleDOI
TL;DR: A particular computer‐based sound spectrograph is described in which digitized time waveforms stored on disk memory are spectrally analyzed and the resulting data stored back on disk for later display.
Abstract: Sound spectrographs based on digital computers are of interest because of the versatility they offer in generating and displaying sound spectrograms. A particular computer‐based sound spectrograph is described in which digitized time waveforms stored on disk memory are spectrally analyzed and the resulting data stored back on disk for later display. Analyses are also performed to obtain the voicing fundamental frequency and the overall‐intensity level of the signal which are displayed time registered with the spectrogram. While viewing the spectrographic display, the user is able to tailor the display before making hardcopy. This permits the user to specify a spectral threshold level, the dynamic range represented in the display, spectral contrast, and spectral emphasis.Subject Classification: 70.62, 70.40; 85.32.

2 citations