SPEECH SYNTHESIS FROM A SPECTROGRAPHIC TRACE
First Claim
1. A method of synthesizing an acoustical signal from a spectrograph trace in which component frequency portions of sound are incrementally plotted against time over a predetermined time period with the intensity of the components being represented by varying density of the plots at corresponding frequency-time points, said method comprising the stEps of:
- scanning said trace successively for said incremental frequency portions over said period and deriving analog signals of amplitude as a function of the density of the plot of the respective frequencies;
synchronously with the scanning of the trace generating oscillation signals at the respective scanning frequencies during said period and amplitude-modulating said oscillation signals by the analog signals of amplitude to produce amplitude-modulated oscillation signals;
recording said amplitude-modulated oscillation signals upon a medium in a multiplicity of tracks;
scanning said medium and generating automatically in response to the scanning of the medium a reproduction of the recorded signals to produce a synthesized acoustic signal corresponding to a summation of the amplitude-modulated signals.
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Abstract
A voice synthesis system using a sound spectrogram, showing the spectrum in the form of a plot of frequency against time with intensity being represented by the variable density of the plot. The spectrogram is scanned and analog signals are produced the amplitude of which is a function of the density of the spectrogram plot. Synchronously with the production of the analog signals oscillation signals are produced at the respective scanning frequencies and are amplitude modulated by the analog signal. The amplitude modulated oscillation signals are stored and summed and subsequently reproduced thereby synthesizing an acoustic signal.
3 Citations
23 Claims
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1. A method of synthesizing an acoustical signal from a spectrograph trace in which component frequency portions of sound are incrementally plotted against time over a predetermined time period with the intensity of the components being represented by varying density of the plots at corresponding frequency-time points, said method comprising the stEps of:
- scanning said trace successively for said incremental frequency portions over said period and deriving analog signals of amplitude as a function of the density of the plot of the respective frequencies;
synchronously with the scanning of the trace generating oscillation signals at the respective scanning frequencies during said period and amplitude-modulating said oscillation signals by the analog signals of amplitude to produce amplitude-modulated oscillation signals;
recording said amplitude-modulated oscillation signals upon a medium in a multiplicity of tracks;
scanning said medium and generating automatically in response to the scanning of the medium a reproduction of the recorded signals to produce a synthesized acoustic signal corresponding to a summation of the amplitude-modulated signals.
- scanning said trace successively for said incremental frequency portions over said period and deriving analog signals of amplitude as a function of the density of the plot of the respective frequencies;
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2. The method defined in claim 1 wherein said signals are additively combined by simultaneously reproducing signals from all of the recorded trace.
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3. The method defined in claim 1 wherein the acoustical signal reproduced from the recording of said amplitude-modulated oscillation signals is substantially identical to the acoustical input forming said spectrographic trace.
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4. The method defining in claim 3, further comprising the step of subtracting a part of the acoustical signal represented by said spectrographic trace prior to reproducing the recorded amplitude-modulated oscillation signals.
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5. The method defined in claim 4 wherein said spectrographic trace is a voice spectrogram of the pronunciation of an individual.
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6. The method defined in claim 1, further comprising the steps of preparing said spectrographic trace prior to the scanning thereof, by plotting component waves of an acoustical input along incremental frequency bands against time over said period while recording the intensity of the component waves as relative lightness and darkness of the respective plots at the corresponding frequency-time points;
- and modifying at least a portion of the plotted information prior to the scanning of the spectrographic and trace acoustically comparing the synthesized acoustic signal with the original acoustic input.
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7. The method defined in claim 6 wherein a further spectrographic trace is produced from the spectrographic trace as first prepared by modifying information relating to at least some of the component frequencies, said further spectrographic trace being subjected to the scanning step.
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8. The method defined in claim 6 wherein the component waves of the acoustic input are plotted successively in said incremental frequency bands.
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9. A method of synthesizing an acoustical signal from a spectrographic trace in which component frequency portions of sound are incrementally plotted against time over a predetermined time period with the intensity of the components being represented by varying density of the plots at corresponding frequency-time points, said method comprising the steps of:
- scanning said trace successively for said incremental frequency portions over said period and deriving analog signals of amplitude as a function of the density of the plot of the respective frequencies;
synchronously with the scanning of the trace generating oscillation signals at the respective scanning frequencies during said period and amplitude-modulating said oscillation signals by the analog signals of amplitude to produce amplitude-modulated oscillation signals;
recording said amplitude-modulated oscillation signals upon a medium; and
scanning said medium and generating automatically in response to the scanning of the medium a reproduction of the recorded signals to produce a synthesized acoustic signal corresponding to a summation of the amplitude-modulated signals, each amplitude-modulated oscillation signal but the first being combined with a previously recorded amplitude-modulated oscillation signal during a previous scan whereby the final recording represents a summation of all of said amplitude-modulated oscIllation signals on a single track.
- scanning said trace successively for said incremental frequency portions over said period and deriving analog signals of amplitude as a function of the density of the plot of the respective frequencies;
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10. The method defined in claim 9 wherein said trace is a visible spectrogram and said density is the relative darkness of parts of the trace.
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11. The method defined in claim 9 wherein said spectrographic trace is formed from an acoustical input.
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12. The method defined in claim 9 wherein said spectrographic trace is prepared artificially based upon analysis of related sound.
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13. A method of analyzing an acoustic input, comprising the steps of:
- a. detecting successive incremental frequency bands of the acoustic input and resonating a mechanical element at the band frequency with an oscillation amplitude representing the intensity of the corresponding frequency band;
b. recording for each incremental frequency band detected in step (a), a visible plot with the amplitude of the corresponding frequency band at each instant of time during a time interval represented by a corresponding degree of darkness of the plot, thereby forming a spectrographic trace in which component frequency waves of the acoustic input are incrementally plotted against time over a given time period with the intensity of the component waves indicated by relative darkness of the plots at the corresponding frequency-time points;
c. optically scanning said trace successively for said incremental frequencies and deriving an electrical output of an amplitude varying with time in accordance with the relative darkness of the plot of the corresponding frequency;
d. generating an electrical oscillation of a frequency corresponding to each of the scanned frequencies in step (c) and amplitude modulating the electrical oscillation with the corresponding electrical output of step (c) to form amplitude-modulated oscillation signals;
e. electrically combining the amplitude-modulated oscillation signals of step (d) for the incremental frequencies; and
f. automatically converting the combined amplitude-modulated oscillation signals of step (e) into an acoustic output.
- a. detecting successive incremental frequency bands of the acoustic input and resonating a mechanical element at the band frequency with an oscillation amplitude representing the intensity of the corresponding frequency band;
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14. The method defined in claim 13 wherein said amplitude-modulated oscillation signals are combined in step (e) by recording the first amplitude-modulated oscillation signal upon one recording track, recording the next amplitude-modulated oscillation signal and the previously recorded amplitude-modulated oscillation signal upon another recording track while cancelling the previously made recording, and repeating the recordal and cancellation steps until one of said tracks carries a recording of the combined amplitude-modulated oscillation signals.
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15. The method defined in claim 13 wherein said amplitude-modulated oscillation signals are combined by recording them individually upon a single recording medium.
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16. An apparatus for the synthesis of an acoustic output from a spectrographic trace in which component frequency portions of an original sound are incrementally plotted against time over a predetermined time period with the intensity of the components being represented by varying density of the plots at corresponding frequency-time points, said apparatus comprising:
- scanning means for repetitively scanning said trace successively for said incremental frequencies and deriving for each of the scanned frequencies analog signals of an amplitude varying with the time in proportion to the density of the plots of the respective component frequencies;
oscillator means operatively connected with said scanning means for producing respective oscillation signal corresponding to each of the scanning frequencies;
amplitude-modulating means connected with said scanning means and with said oscillator means for producing an amplitude-modulated oscillation signal as a function of time for each of the scanned frequencies;
means for combining at least some of said amplitude-modulated oscillation signals; and
electroacoustic transducer means for producing an acoustical output corresponding to the combined amplitude-modulated oscillation signals.
- scanning means for repetitively scanning said trace successively for said incremental frequencies and deriving for each of the scanned frequencies analog signals of an amplitude varying with the time in proportion to the density of the plots of the respective component frequencies;
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17. The apparatUs defined in claim 16 wherein said trace is visible and the varying density of said plots is represented by different degrees of darkness, said scanning means including an optical scanner adapted to sweep said trace and provided with a source of illumination trained at said plots successively and optically sensitive pickup means receiving reflected light from said plots for detecting the degree of darkness thereof.
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18. The apparatus defined in claim 16 wherein said means for combining said amplitude-modulated oscillation signals includes a single recording medium and means for recording said amplitude-modulated oscillation signals successively on separate tracks of said medium.
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19. The apparatus defined in claim 16 wherein said scanning means includes a drum carrying said trace and rotatable about an axis parallel to the time axis of said trace and a scanning head displaceable parallel to a generatrix of said drum, said oscillator means comprising a variable-frequency oscillator having a frequency-selection member and means operatively connecting said head with said member.
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20. An apparatus for the synthesis of an acoustic output from a spectrographic trace in which component frequency portions of an original sound are incrementally plotted against time over a predetermined time period with the intensity of the components being represented by varying density of the plots at corresponding frequency-time points, said apparatus comprising:
- scanning means for repetitively scanning said trace successively for said incremental frequencies and deriving for each of the scanned frequencies analog signals of an amplitude varying with the time in proportion to the density of the plots of the respective component frequencies;
oscillator means operatively connected with said scanning means for producing respective oscillation signal corresponding to each of the scanning frequencies;
amplitude-modulating means connected with said scanning means and with said oscillator means for producing an amplitude-modulated oscillation signal as a function of time for each of the scanned frequencies;
means for combining at least some of said amplitude-modulated oscillation signals; and
electroacoustic transducer means for producing an acoustical output corresponding to the combined amplitude-modulated oscillation signals, said means for combining said amplitude-modulated oscillation signals including a pair of synchronously driven recording tracks, recording means associated with each of said tracks, playback means associated with each of said tracks, cancellation means associated with each of said tracks, and switch means operable to connect the recording means of one of said tracks to said amplitude-modulating means and the playback means of the other of said tracks to said recording means of said one of said tracks to record the amplitude-modulated oscillation signal of the frequency currently scanned by said scanning means upon said one of said tracks concurrently with a previously recorded amplitude-modulated oscillation signal from said other track, while cancelling the recorded signal on said other track.
- scanning means for repetitively scanning said trace successively for said incremental frequencies and deriving for each of the scanned frequencies analog signals of an amplitude varying with the time in proportion to the density of the plots of the respective component frequencies;
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21. An apparatus for the synthesis of an acoustic output from a spectrographic trace in which component frequency portions of an original sound are incrementally plotted against time over a predetermined time period with the intensity of the components being represented by varying density of the plots at corresponding frequency-time points, said apparatus comprising:
- scanning means for repetitively scanning said trace successively for said incremental frequencies and deriving for each of the scanned frequencies analog signals of an amplitude varying with the time in proportion to the density of the plots of the respective component frequencies;
oscillator means operatively connected with said scanning means for producing respective oscillation signals corresponding to each of the scanning frequencies;
amplitude-modulating mEans connected with said scanning means and with said oscillator means for producing an amplitude-modulated oscillation signal as a function of time for each of the scanned frequencies;
means for combining at least some of said amplitude-modulated oscillation signals;
electroacoustic transducer means for producing an acoustical output corresponding to the combined amplitude-modulated oscillation signals;
sound-analyzing means for producing said trace and including vibratory means having a resonance-shifting member, means responsive to an acoustical input for energizing said vibratory means; and
means responsive to the amplitude of vibration of said vibratory means at successive resonant frequencies thereof for forming said trace.
- scanning means for repetitively scanning said trace successively for said incremental frequencies and deriving for each of the scanned frequencies analog signals of an amplitude varying with the time in proportion to the density of the plots of the respective component frequencies;
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22. The apparatus defined in claim 21 wherein said sound analyzing means includes a recording head adapted to sweep a recording medium for producing an electrical discharge forming visible marks thereon.
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23. The apparatus defined in claim 21 wherein said vibratory means includes a tuning fork, said member being shiftable between the arms of said fork, said input means constituting a first electromagnetic transducer co-operating with one of said arms and said output means constituting a second electromagnetic transducer co-operating with the other of said arms.
Specification