Formant tracker

Claim 2

A formant tracker for receiving an analog signal, said formant tracker comprising: means for tracking a pitch associated with the analog signal and generating a fundamental frequency therefrom; and means operably coupled to the output of said pitch tracking means for receiving the fundamental frequency of the analog signal to determine at least one formant within a frequency spectrum in which the analog signal is found, said formant determining means including means establishing an integer set including a plurality of integers associated with at least a selected frequency range containing said at least one formant and within said frequency spectrum in which the analog signal is found, and means for establishing within said integer set over the plurality of integers contained therein an optimal integer for said selected frequency range within said frequency spectrum from said integer set and a bandwidth associated with said optimal integer; said formant determining means generating said at least one formant in response to the product of said optimal integer and said fundamental frequency.

Claim 3

A formant tracker as set forth in claim 1, wherein said means for establishing an optimal integer comprises: means for iteratively generating for each of said plurality of integers within said integer set a sinusoidal signal from said fundamental frequency as multiplied by successive ones of said integers during respective iterations, means for convolving said sinusoidal signal with said analog signal over the selected frequency range containing said at least one formant and within said frequency spectrum in which the analog signal is found to obtain a convolution having a variable amplitude, and means for choosing said optimal integer based upon the maximum amplitude of said convolution.

Claim 4

A formant tracker as set forth in claim 2, wherein said means for convolving said sinusoidal signal with said analog signal comprises integrating means for integrating the product of said sinusoidal signal and said analog signal over the selected frequency range containing said at least one formant and within said frequency spectrum in which the analog signal is found.

Claim 5

A formant tracker for receiving an analog signal, said formant tracker comprising: means for tracking a pitch associated with the analog signal and generating a fundamental frequency therefrom; means operably coupled to the output of said pitch tracking means for receiving the fundamental frequency of the analog signal to determine a plurality of formants within a frequency spectrum in which the analog signal is found, said formant determining means including means establishing respective integer sets each of which includes a plurality of integers and associated with different selected frequency ranges containing respective formants and within said frequency spectrum in which the analog signal is found, and means for establishing within each said integer set over the plurality of integers contained therein an optimal integer for said selected frequency range corresponding thereto within said frequency spectrum from said respective integer set and a bandwidth associated with each said optimal integer; said formant determining means generating said plurality of formants in response to the respective products of each of said optimal integers and said fundamental frequency.

Claim 6

A formant tracker for receiving an analog signal, said formant tracker comprising: means for tracking a pitch associated with the analog signal and generating a fundamental frequency therefrom; means operably coupled to the output of said pitch tracking means for receiving the fundamental frequency of the analog signal to determine a plurality of formants within a frequency spectrum in which the analog signal is found, said formant determining means including means establishing respective integer sets each of which includes a plurality of integers and associated with different selected frequency ranges containing respective formants and within said frequency spectrum in which the analog signal is found, and means for establishing within each said integer set over the plurality of integers contained therein an optimal integer for said selected frequency range corresponding thereto within said frequency spectrum from said respective integer set and a bandwidth associated with each said optimal integer; said formant determining means generating said plurality of formants in response to the respective products of each of said optimal integers and said fundamental frequency.

Claim 7

A formant tracker as set forth in claim 4, wherein said integer set establishing means is effective to establish three respective integer sets each of which includes a plurality of integers and associated with three different selected frequency ranges containing respective formants and within said frequency spectrum in which the analog signal is found, and said optimal integer establishing means being effective to establish three optimal integers for said three different selected frequency ranges, such that said formant determining means generates three formants in response to the respective products of each of said three optimal integers and said fundamental frequency.

Claim 8

A formant tracker as set forth in claim 5, wherein said three different selected frequency ranges within said frequency spectrum in which the analog signal is found comprise the respective ranges 200-850 hertz, 850-2500 hertz, and 2500-3500 hertz.

Claim 9

A formant tracker as set forth in claim 6, wherein said three different selected frequency ranges within said frequency spectrum in which the analog signal is found effectively define human speech.

Claim 10

A formant tracker as set forth in claim 7, further including automatic gain control circuit means connected to the input of said pitch tracking means for receiving a speech signal and generating the analog signal therefrom for input to said pitch tracking means.

Claim 11

Apparatus for generating indicia representative of an analog signal corresonding to human speech, wherein the indicia includes a plurality of formants within different selected frequency ranges of the analog signal, with each of said formants being contained within a different one of said selected frequency ranges and said formants collectively being definitive of human speech, said apparatus comprising: means for determining a fundamental frequency from said analog signal; plural formant determining means operably coupled to the output of said fundamental frequency determining means for respectively identifying individual formants within the frequency spectrum in which the analog signal is found as contained within said different selected frequency ranges, each of said formant determining means including means establishing a respective integer set including a plurality of integers associated with a selected frequency range containing a respective formant and within said frequency spectrum in which the analog signal is found, said selected frequency range being different from the selected frequency ranges of the other formant determining means, means for iteratively generating for each of said plurality of integers within said integer set a sinusoidal signal from said fundamental frequency as multiplied by successive ones of said integers during respectively iterations, means for convolving said sinusoidal signal with said analog signal over the respective selected frequency range containing said formant to obtain a convolution having a variable amplitude, and means for choosing an optimal integer for said selected frequency range based upon the maximum amplitude of said convolution; each of said formant determining means generating a respective one of said plurality of formants in response to the respective products of each of said optimal integers and said fundamental frequency; and means for determining respective bandwidths associated with each of said plurality of formants; and output means operably coupled to said fundamental frequency determining means, said plural formant determining means, and said bandwidth determining means for providing said plurality of formants and said bandwidths respectively associated therewith along with said fundamental frequency as indicia representative of said analog signal.

Claim 12

Apparatus for generating indicia representative of an analog signal corresonding to human speech, wherein the indicia includes a plurality of formants within different selected frequency ranges of the analog signal, with each of said formants being contained within a different one of said selected frequency ranges and said formants collectively being definitive of human speech, said apparatus comprising: means for determining a fundamental frequency from said analog signal; plural formant determining means operably coupled to the output of said fundamental frequency determining means for respectively identifying individual formants within the frequency spectrum in which the analog signal is found as contained within said different selected frequency ranges, each of said formant determining means including means establishing a respective integer set including a plurality of integers associated with a selected frequency range containing a respective formant and within said frequency spectrum in which the analog signal is found, said selected frequency range being different from the selected frequency ranges of the other formant determining means, means for iteratively generating for each of said plurality of integers within said integer set a sinusoidal signal from said fundamental frequency as multiplied by successive ones of said integers during respectively iterations, means for convolving said sinusoidal signal with said analog signal over the respective selected frequency range containing said formant to obtain a convolution having a variable amplitude, and means for choosing an optimal integer for said selected frequency range based upon the maximum amplitude of said convolution; each of said formant determining means generating a respective one of said plurality of formants in response to the respective products of each of said optimal integers and said fundamental frequency; and means for determining respective bandwidths associated with each of said plurality of formants; and output means operably coupled to said fundamental frequency determining means, said plural formant determining means, and said bandwidth determining means for providing said plurality of formants and said bandwidths respectively associated therewith along with said fundamental frequency as indicia representative of said analog signal.

Claim 13

Apparatus as set forth in claim 9, wherein said means for convolving said sinusoidal signal with said analog signal for each of said formant determining means comprises integrating means for integrating the product of said sinusoidal signal and said analog signal over the respective selected frequency ranges associated with each of said formant determining means.

Claim 14

Apparatus as set forth in claim 10, wherein said means for iteratively generating a sinusoidal signal for each of said formant determining means includes a sinusoidal oscillator connected to the output of said fundamental frequency determining means.

Claim 15

Apparatus as set forth in claim 11, wherein said fundamental frequency determining means comprises a pitch tracker.

Claim 16

Apparatus as set forth in claim 12, wherein three formant determining means are provided respectively corresponding to three different selected frequency ranges 200-850 hertz, 850-2500 hertz, and 2500-3500 hertz.

Claim 19

A method as set forth in claim 14, wherein said optimal integer is determined by iteratively generating for each of said plurality of integers within said integer set a sinusoidal signal from said fundamental frequency as multiplied by successive ones of said integers during respective iterations; convolving said sinusoidal signal with said analog signal over the selected frequency range containing said at least one formant and within said frequency spectrum in which the analog signal is found to obtain a convolution having a variable amplitude; and choosing the optimal integer based upon the maximum amplitude of said convolution.

Claim 20

A method as set forth in claim 15, wherein a plurality of formants are identified from the analog signal, including establishing a plurality of different selected frequency ranges each of which contains a respective formant wherein all of said selected frequency ranges lie within said frequency spectrum in which the analog signal is found; establishing an integer set including a plurality of integers for each of the different selected frequency ranges containing respective formants; determining an optimal integer for each of said integer sets and corresponding to the respective different selected frequency ranges; and generating a plurality of formants by obtaining the respective products of each of said optimal integers and said fundamental frequency.