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US 4,063,035 AGranted
Device for visually displaying the auditory content of the human voice
AssigneeIndiana University Foundation
InventorsDudley Ralph Appelman, David Allen Link, Gerald Louret Stout
Life of this patent
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Abstract
A voiced-sound frequency analysis and display system displays two forms of spectral information about the signal: (1) the first and second formants as a point on an X-Y grid of a cathode ray tube, and (2) the full spectrum as a bar graph on an oscilloscope. Two sets of filters with associated circuitry perform the analysis. A scanning (peak hunting) second-formant selector circuit is also disclosed.
Claims17
A device for visually displaying the auditory content of the human voice comprising:
- input means for receiving human voice utterances and for converting the auditory content of the voice utterances to an electronic audio signal having a frequency spectrum;
- a first set of filter means covering a first formant frequency range of the frequency spectrum of the voice utterances for separating the electronic audio signal into a first set of individual frequency signals;
- a second set of filter means covering a second formant frequency range of the frequency spectrum of the voice utterances for separating the electronic audio signal into a second set of individual frequency signals;
- first comparator means for comparing the first set of individual frequency signals and selecting and transmitting the individual frequency signal of the first set having the greatest magnitude;
- second comparator means for comparing the second set of individual frequency signals and selecting and transmitting the individual frequency signal of the second set having the greatest magnitude;
- first converter means for converting the selected individual frequency signal from the first comparator means to a first voltage representative of the frequency of the selected frequency signal of the first set;
- second converter means for converting the selected individual frequency signal from the second comparator means to a second voltage representative of the frequency of the selected frequency signal of the second set;
- a display means including a cathode ray tube having a vertical input and a horizontal input, said first voltage from said first converter means being applied to said vertical input, and said second voltage from said second converter means being applied to said horizontal input so that a luminescent dot appears on the face of said cathode ray tube at a vertical and horizontal position corresponding to the values of said first and said second voltages.
5 more elements
A device for visually displaying the auditory content of the human voice comprising:
- a sound transducer for receiving human voice utterances and converting the human voice utterances to an electronic audio signal having a frequency spectrum;
- a high pass filter means for filtering out a fundamental frequency of the frequency spectrum of said electronic audio signal;
- a peak limiter means for limiting the maximum amplitude of said electronic audio signal;
- a plurality of band pass filter means for dividing said frequency spectrum into a corresponding plurality of individual frequency signals each having a frequency range corresponding to a section of said frequency spectrum;
- a plurality of comparator means each for receiving one of said individual frequency signals and converting said individual frequency signals to a corresponding DC voltage of comparable amplitude, said plurality of comparator means being arranged to provide a first and second logic signal corresponding to the individual frequency signals in a first and a second overlapping formant range corresponding to the individual frequency signal in each formant range having the greatest amplitude;
- a first switch means for receiving said first logic signal and transmitting said individual frequency signal in said first formant range having the greatest amplitude corresponding to said first logic signal;
- a second switch means for receiving said second logic signal and transmitting said individual frequency signal in said second formant range having the greatest amplitude corresponding to said second logic signal;
- a first converter means for converting said transmitted individual frequency signal in the first formant range to a first voltage signal having an amplitude representative of the frequency of said signal;
- a second converter means for converting said transmitted individual frequency signal in the second range to a second voltage signal having an amplitude representative of the frequency of said signal;
- a display means including a cathode ray tube for receiving said first and second voltage signals and deflecting an electron beam on the face of said cathode ray tube to a position corresponding to the frequency of said individual frequency signals.
7 more elements
Dependencies are inferred from the claim text.