Digital speech signal synthesizer

Claim 2

A signal synthesizer comprising: input means connected to receive a digital frame from a suitable source, said digital frame containing a plurality of frequency information bits and a plurality of spectrum-segment amplitude information bits; a spectrum component generator connected to receive said frequency information bits from said input means and operative to generate all spectrum components of the frequency identified by said frequency information bits; storage register means connected to said input means and to said spectrum component generator to receive and store said amplitude information bits, and under generation of each spectrum component by said spectrum component generator, to pass a predetermined number Of said amplitude information bits; first means connected to said spectrum component generator and to said storage register to sequentially receive each spectrum component together with the corresponding amplitude information bits and operative to generate a digital signal indicative of a respective point of an amplitude modulated trigonometric function defined by each said spectrum component and the corresponding amplitude information bits; adder means connected to receive the signals from said first means and operative to pass the digital total signal indicative of the sum of the signals from said first means; second means for applying a signal to said spectrum component generator and said adder means and responsive to a preselected limit frequency to cause said adder means to pass said digital total signal and to cause said spectrum component generator to repeat the generation of said spectrum components to thereby cause said first means to generate additional pluralities of digital signals, each indicative of a respective subsequent point of said amplitude modulated trigonometric function; reset means connected to said second means and said input means and operative in response to operation of said second means of preselected number of times to clear said input means for receipt of a new digital frame; and means connected to receive the output of said adder means for generating a time-varying analog signal indicative of said output of said adder means.

Claim 3

The signal synthesizer of claim 1 including: comparator means connected to detect generation by said spectrum component generator of all spectrum components of a preselected frequency in each of a plurality of preselected frequency band and operative in response to detection of each said predetermined frequency to activate said storage register means to pass said predetermined number of amplitude information bits.

Claim 4

The signal synthesizer of claim 1 wherein said storage register means comprises: recirculating means connected to store said amplitude information bits for subsequent re-use; and clearing means connected to said reset means and operative in response to a signal from said reset means to clear said recirculating means.

Claim 5

The signal synthesizer of claim 1 wherein said first means includes: addressing means connected to receive said spectrum components from said spectrum component generator and for emitting a digital signal indicative of a sine wave segment defined by said spectrum components.

Claim 6

The signal synthesizer of claim 4 wherein: said addressing means is connected to said second means and is operative in response to signals from said second means to emit a signal indicative of a subsequent segment of the sine wave defined by the spectrum component.

Claim 7

The signal synthesizer of claim 5 wherein said first means further includes: memory means addressed by signals from said addressing means and said amplitude information bits and operative to emit a digital signal indicative of a respective point of an amplitude-modulated sine wave.

Claim 8

The signal synthesizer of claim 6 wherein: said memory means is a read-only memory.

Claim 9

The signal synthesizer of claim 4 further comprising: noise generator means connected to said input means for detecting an ''''all zero'''' frequency indication and operative in response thereto to pass a predetermined noise signal to said addressing means.

Claim 10

The signal synthesizer of claim 8 wherein: said noise generator responds to said ''''all zero'''' frequency indication by applying a predetermined frequency to said spectrum component generator and applying to said addressing means a random noise value.

Claim 11

The signal synthesizer of claim 1 wherein said first means includes: sine segment generator means connected to receive said frequency information bits from said input means and operative to generate a digital output signal indicative of the sine wave defined by said frequency information bits; and triggering means connected to said sine segment generator means and operative at predetermined intervals to cause said sine segment generator means to pass portions of said digital output signal representing predetermined, sequential segments of said sine wave.

Claim 12

The signal synthesizer of claim 10 wherein said first means further includes: segment spectrum component generator means connected to receive said portions of said digital output signal passed by said sine segment generator means and operative to generate a plurality of digital signals each indicative of a spectrum component of the sine wave segment identified by the signals from said sine segment generator means.

Claim 13

A signal synthesizer comprising: input means connected to receive a digital frame from a suitable source, said digital frame containing a plurality of frequency information bits and a plurality of spectrum-segment amplitude information bits; a spectrum component generator connected to receive said frequency information bits from said input means and operative to generate all spectrum components to the frequency identified by said frequency information bits; storage register means connected to said input means and to said spectrum component generator to receive and store said amplitude information bits, and upon generation of each said spectrum component by said spectrum component generator, to pass a predetermined number of said amplitude information bits, said storage register means including recirculating means connected to store said amplitude information bits for subsequent re-use and clearing means operative in response to a signal to clear said recirculating means; comparator means connected to detect generation by said spectrum component generator of all spectrum components of a preselected frequency each of a plurality of preselected frequency bands and operative in response to detection of each said predetermined frequency to activate said storage register means to pass said predetermined number of amplitude information bits; first means connected to said spectrum component generator and to said storage register means to sequentially receive each spectrum component together with the corresponding amplitude information bits and operative to generate a digital signal indicative of a respective point of an amplitude-modulated trigonometric function defined by each said spectrum component and the corresponding amplitude information bits; adder means connected to receive the signals from said first means and operative to pass a digital total signal indicative of the sum of the signals from said first means; of second means for applying a signal to said spectrum component generator and said adder means and responsive to a preselected limit frequency to cause said adder means to pass said digital total signal and to cause said spectrum component generator to repeat the generation of said spectrum components to thereby cause said first means to generate additional pluralities of digital signals, each indicative rf a respective subsequent point of said amplitude-modulated trigonometric function; reset means connected to said second means and said input means and to said clearing means of said storage register and operative in response to operation of said second means a preselected number of times to clear said digital input means for receipt of a new digital frame; and means connected to receive the output of said adder means for generating a time-varying analog signal indicative of said output of said adder means.

Claim 14

A signal synthesizer comprising: input means connected to receive a digital frame from a suitable source, said digital frame containing a plurality of frequency information bits and a plurality of spectrum-segment amplitude information bits; a spectrum component generator connected to receive said frequency information bits from said input means and operative to generate all spectrum components to the frequency identified by said frequency information bits; storage register means connected to said input means and to said spectrum component generator to receive and store said amplitude information bits, and upon generation of each said spectrum component by said spectrum component generator, to pass a predetermined number of said amplitude information bits, said storage register means including recirculating means connected to store said amplitude information bits for subsequent re-use and clearing means operative in response to a signal to clear said recirculating means; comparator means connected to detect generation by said spectrum component generator of all spectrum components of a preselected frequency each of a plurality of preselected frequency bands and operative in response to detection of each said predetermined frequency to activate said storage register means to pass said predetermined number of amplitude information bits; first means connected to said spectrum component generator and to said storage register means to sequentially receive each spectrum component together with the corresponding amplitude information bits and operative to generate a digital signal indicative of a respective point of an amplitude-modulated trigonometric function defined by each said spectrum component and the corresponding amplitude information bits; adder means connected to receive the signals from said first means and operative to pass a digital total signal indicative of the sum of the signals from said first means; of second means for applying a signal to said spectrum component generator and said adder means and responsive to a preselected limit frequency to cause said adder means to pass said digital total signal and to cause said spectrum component generator to repeat the generation of said spectrum components to thereby cause said first means to generate additional pluralities of digital signals, each indicative rf a respective subsequent point of said amplitude-modulated trigonometric function; reset means connected to said second means and said input means and to said clearing means of said storage register and operative in response to operation of said second means a preselected number of times to clear said digital input means for receipt of a new digital frame; and means connected to receive the output of said adder means for generating a time-varying analog signal indicative of said output of said adder means.

Claim 15

The signal synthesizer of claim 12 wherein said first means includes: addressing means connected to receive said spectrum component from said spectrum component generator and to emit a digital signal indicative of a sine wave segment defined by said spectrum component.

Claim 16

The signal synthesizer of claim 13 wherein: said addressing means is connected to said second means and is operative in response To signals from said second means to emit a signal indicative of a subsequent segment of the sine wave defined by spectrum component.

Claim 17

The signal synthesizer of claim 14 wherein said first means includes: memory means addressed by signals from said addressing means and said amplitude information bits and operative to emit a digital signal indicative of a respective point of an amplitude-modulated sine wave.

Claim 18

The signal synthesizer of claim 15 further comprising: noise generator means connected to said input means for detecting an ''''all zero'''' frequency indication and operative in response thereto to pass a predetermined noise signal to said addressing means.

Claim 19

The signal synthesizer of claim 16 wherein: said noise generator responds to said ''''all zero'''' frequency indication by applying a predetermined frequency to said spectrum component generator and applying to said addressing means a random noise value.

Claim 20

A signal synthesizer comprising: input means connected to receive a digital frame from a suitable source, said digital frame containing a plurality of frequency information bits and a plurality of spectrum-segment amplitude information bits; a spectrum component generator connected to receive said frequency information bits from said input means and operative to generate all spectrum components of the frequency identified by said frequency information bits; storage register means connected to said input means and to said spectrum component generator to receive and store said amplitude information bits, and upon generation of each spectrum component by said spectrum component generator, to pass a predetermined number of said amplitude information bits; first means connected to said spectrum component generator and to said storage register to sequentially receive each spectrum component together with the corresponding amplitude information bits and operative to generate a digital signal indicative of a respective point of an amplitude modulated trigonometric function defined by each said spectrum component and the corresponding amplitude information bits, said first means including addressing means connected to receive said spectrum components from said spectrum component generator and for emitting a digital signal indicative of a sine wave segment defined by said components and memory means addressed by said sine wave segment signals and said amplitude information bits and operative to emit the digital signals indicative of a respective point of an amplitude-modulated trigonometric function; noise generator means connected to said input means for detecting an ''''all-zero'''' frequency indication and operative in response thereto to pass a predetermined noise signal to the addressing means of said first means, said noise generator responds to said ''''all-zero'''' frequency indication by applying a predetermined frequency to said spectrum component generator and applying to said addressing means a random noise value; adder means connected to receive the signals from said first means and operative to pass a digital total signal indicative of the sum of the signals from said first means; second means for applying a signal to said spectrum component generator and said adder means and responsive to a preselected limit frequency to cause said adder means to pass said digital total signal and to cause said spectrum component generator to repeat the generation of said spectrum components to thereby cause said first means to generate additional pluralities of digital signals, each indicative of a respective subsequent point of said amplitude-modulated trigonometric function; reset means connected to said second means and said input means and operative in response to operation of said second means a preselected number of times to clear said input means for receipt of a new digital frame; and means connected to receive the output of said adder means for generating a time-varying analog signal indicative of said output of said adder means.

Claim 21

A signal synthesizer comprising: input means connected to receive a digital frame from a suitable source, said digital frame containing a plurality of frequency information bits and a plurality of spectrum-segment amplitude information bits; a spectrum component generator connected to receive said frequency information bits from said input means and operative to generate all spectrum components of the frequency identified by said frequency information bits; storage register means connected to said input means and to said spectrum component generator to receive and store said amplitude information bits, and upon generation of each spectrum component by said spectrum component generator, to pass a predetermined number of said amplitude information bits; first means connected to said spectrum component generator and to said storage register to sequentially receive each spectrum component together with the corresponding amplitude information bits and operative to generate a digital signal indicative of a respective point of an amplitude modulated trigonometric function defined by each said spectrum component and the corresponding amplitude information bits, said first means including addressing means connected to receive said spectrum components from said spectrum component generator and for emitting a digital signal indicative of a sine wave segment defined by said components and memory means addressed by said sine wave segment signals and said amplitude information bits and operative to emit the digital signals indicative of a respective point of an amplitude-modulated trigonometric function; noise generator means connected to said input means for detecting an ''''all-zero'''' frequency indication and operative in response thereto to pass a predetermined noise signal to the addressing means of said first means, said noise generator responds to said ''''all-zero'''' frequency indication by applying a predetermined frequency to said spectrum component generator and applying to said addressing means a random noise value; adder means connected to receive the signals from said first means and operative to pass a digital total signal indicative of the sum of the signals from said first means; second means for applying a signal to said spectrum component generator and said adder means and responsive to a preselected limit frequency to cause said adder means to pass said digital total signal and to cause said spectrum component generator to repeat the generation of said spectrum components to thereby cause said first means to generate additional pluralities of digital signals, each indicative of a respective subsequent point of said amplitude-modulated trigonometric function; reset means connected to said second means and said input means and operative in response to operation of said second means a preselected number of times to clear said input means for receipt of a new digital frame; and means connected to receive the output of said adder means for generating a time-varying analog signal indicative of said output of said adder means.

Claim 22

The signal synthesizer of claim 18 wherein: said memory means is a read-only memory.

Claim 23

A signal synthesizer comprising: input means connected to receive a digital frame from a suitable source, said digital frame containing a plurality of frequency information bits and a plurality of spectrum-segment amplitude information bits; a spectrum component generator connected to receive said frequency information bits from said input means and operative to generate all spectrum components of the frequency identified by said frequency information bits; storage register means connected to said input means and to said spectrum component generator to receive and store said amplitude information bits, and upon generation of each spectrum component by said spectrum component generator, to pass a predetermined number of said amplitude information bits; first means connected to said spectrum component generator and to said storage register to sequentially receive each component together with the corresponding amplitude information bits and operative to generate a digital signal indicative of a respective point of an amplitude-modulated trigonometric function defined by each said spectrum component and the corresponding amplitude information bits; said first means including addressing means connected to receive said spectrum components from said spectrum component generator and for emitting a digital signal indicative of a sine wave segment defined by said spectrum components; noise generator means connected to said input means for detecting an ''''all-zero'''' frequency indication and operative in response thereto to pass a predetermined noise signal to said addressing means, said noise generator responding to said ''''all-zero'''' frequency indication by applying a predetermined frequency to said spectrum component generator and applying to said segment spectrum component generator a quasi-random noise value associated with each spectrum component generated by said spectrum component generator; adder means connected to receive the signals from said first means and operative to pass a digital total signal indicative of the sum of the signals from said first means; second means for applying a signal to said spectrum component generator and said adder means and responsive to a preselected limit frequency to cause said adder means to pass said digital total signal and to cause said spectrum component generator to repeat the generation of said spectrum components to thereby cause said first means to generate additional pluralities of digital signals, each indicative of a respective subsequent point of said amplitude-modulated trigonometric function; reset means connected to said second means and said input means and operative in response to operation of said second means a preselected number of times to clear said input means for receipt of a new digital frame; and means connected to receive the output of said adder means for generating a time-varying analog signal indicative of said output of said adder means.

Claim 24

A signal synthesizer comprising: input means connected to receive a digital frame from a suitable source, said digital frame containing a plurality of frequency information bits and a plurality of spectrum-segment amplitude information bits; a spectrum component generator connected to receive said frequency information bits from said input means and operative to generate all spectrum components of the frequency identified by said frequency information bits; storage register means connected to said input means and to said spectrum component generator to receive and store said amplitude information bits, and upon generation of each spectrum component by said spectrum component generator, to pass a predetermined number of said amplitude information bits; first means connected to said spectrum component generator and to said storage register to sequentially receive each component together with the corresponding amplitude information bits and operative to generate a digital signal indicative of a respective point of an amplitude-modulated trigonometric function defined by each said spectrum component and the corresponding amplitude information bits; said first means including addressing means connected to receive said spectrum components from said spectrum component generator and for emitting a digital signal indicative of a sine wave segment defined by said spectrum components; noise generator means connected to said input means for detecting an ''''all-zero'''' frequency indication and operative in response thereto to pass a predetermined noise signal to said addressing means, said noise generator responding to said ''''all-zero'''' frequency indication by applying a predetermined frequency to said spectrum component generator and applying to said segment spectrum component generator a quasi-random noise value associated with each spectrum component generated by said spectrum component generator; adder means connected to receive the signals from said first means and operative to pass a digital total signal indicative of the sum of the signals from said first means; second means for applying a signal to said spectrum component generator and said adder means and responsive to a preselected limit frequency to cause said adder means to pass said digital total signal and to cause said spectrum component generator to repeat the generation of said spectrum components to thereby cause said first means to generate additional pluralities of digital signals, each indicative of a respective subsequent point of said amplitude-modulated trigonometric function; reset means connected to said second means and said input means and operative in response to operation of said second means a preselected number of times to clear said input means for receipt of a new digital frame; and means connected to receive the output of said adder means for generating a time-varying analog signal indicative of said output of said adder means.

Claim 25

The signal synthesizer of claim 20 further comprising: means applying said quasi-random noise value to a predetermined number of said sine wave segments and subsequently applying a different quasi-random noise value to succeeding segments of said sine wave segment.

Claim 26

A synthesizer for converting consecutive frames of digital words into analog signals, said consecutive frames including frequency and amplitude information relating to consecutive, predetermined instants of time of a first signal, and one word of each frame containing fundamental frequency information bits relating to the fundamental frequency of the original signal at one instant of time, and other consecutive words of each frame containing amplitude information bits of consecutive, predetermined frequency bands of the original signal, said bands having a predetermined relation to the fundamental frequency of the original signal at one instant of time, said synthesizer including: input means for receiving said consecutive frames of digital words; control means responsive to said one word for providing an output indicative of successive multiples of said fundamental frequency; first means connected to said input means and controlled by the output of said control means for producing successive digital signals relating to the fundamental frequency and indicative of the amplitude denoted by said other digital words of a frame, said means including memory means for producing digital signals indicative of predetermined frequency and predetermined amplitude sine waves, and means operatively associated with said memory means and said input means for causing said memory means to transmit successive digital signals indicative of the amplitude and frequency of sine waves denoted by the words of the frame; adder means for receiving the digital signals from said first means and for producing a digital signal corresponding to each frame and indicative of the sum of the signals corresponding to the words of each frame; and a digital-to-analog converter for receiving the output of said adder means and producing an analog signal corresponding to said first signal.

Claim 27

A synthesizer for converting consecutive frames of digital words into analog signals, said consecutive frames including frequency and amplitude information relating to consecutive, predetermined instants of time of a first signal, and one word of each frame containing fundamental frequency information bits relating to the fundamental frequency of the original signal at one instant of time, and other consecutive words of each frame containing amplitude information bits of consecutive, predetermined frequency bands of the original signal, said bands having a predetermined relation to the fundamental frequency of the original signal at one instant of time, said synthesizer including: input means for receiving said consecutive frames of digital words; control means responsive to said one word for providing an output indicative of successive multiples of said fundamental frequency; first means connected to said input means and controlled by the output of said control means for producing successive digital signals relating to the fundamental frequency and indicative of the amplitude denoted by said other digital words of a frame, said means including memory means for producing digital signals indicative of predetermined frequency and predetermined amplitude sine waves, and means operatively associated with said memory means and said input means for causing said memory means to transmit successive digital signals indicative of the amplitude and frequency of sine waves denoted by the words of the frame; adder means for receiving the digital signals from said first means and for producing a digital signal corresponding to each frame and indicative of the sum of the signals corresponding to the words of each frame; and a digital-to-analog converter for receiving the output of said adder means and producing an analog signal corresponding to said first signal.

Claim 28

The synthesizer of claim 22, wherein frequency bands denoted by said other words of a frame each contain at least one harmonic of the fundamental frequency denoted by said one word of the frame, and means operatively associated with said first means and said input means for causing the digital signals produced by said first means to be indicative of the frequency of the at least one harmonic of the fundamental frequency in each frequency band denoted by said other words and to be indicative of the amplitude energy in each band.

Claim 29

The synthesizer claimed in claim 22 wherein said frequency information bits includes unvoiced signals relating to the absence of a fundamental frequency and the synthesizer includes hiss-generator means responsive to the presence of said unvoiced signals for generating a noise signal simulating unvoiced sounds in speech and for applying the noise signal to the adder means.

Claim 30

A synthesizer for converting consecutive frames of digital words indicative of the frequency spectrum and amplitude of speech at predetermined spaced consecutive instants of time, one word of each frame containing fundamental frequency information bits of voiced speech at one instant of time and other consecutive words of the frame containing amplitude information bits of successive frequency spectrum segments of the speech at the one instant of time said synthesizer including;: input means for receiving said consecutive frames of digital words; generator means connected to said input means for generating successive digital signals corresponding to successive multiples of the fundamental frequency of each frame; first means responsive to the output of said generator means and connected to said input means for providing successive digital signals indicative of the frequency and amplitude of the spectrum segments denoted by successive ones of said other words of the frame, said means including a table of predetermined successive channel bandwidths and comparator means for comparing the output of said generator means with said channel bandwidths of said table for successively transmitting signals and causing said first means to provide successive signals corresponding to the information denoted by said other words upon the generation by said generator means of digital signals corresponding to the least multiple of the fundamental frequency in each successive channel bandwidth; and adder means for receiving said digital signals from said first means and for providing successive digital total signals indicative of the frequency spectrum and amplitude of speech at the instants of time denoted by the frames of digital words.

Claim 31

A synthesizer for converting consecutive frames of digital words indicative of the frequency spectrum and amplitude of speech at predetermined spaced consecutive instants of time, one word of each frame containing fundamental frequency information bits of voiced speech at one instant of time and other consecutive words of the frame containing amplitude information bits of successive frequency spectrum segments of the speech at the one instant of time said synthesizer including;: input means for receiving said consecutive frames of digital words; generator means connected to said input means for generating successive digital signals corresponding to successive multiples of the fundamental frequency of each frame; first means responsive to the output of said generator means and connected to said input means for providing successive digital signals indicative of the frequency and amplitude of the spectrum segments denoted by successive ones of said other words of the frame, said means including a table of predetermined successive channel bandwidths and comparator means for comparing the output of said generator means with said channel bandwidths of said table for successively transmitting signals and causing said first means to provide successive signals corresponding to the information denoted by said other words upon the generation by said generator means of digital signals corresponding to the least multiple of the fundamental frequency in each successive channel bandwidth; and adder means for receiving said digital signals from said first means and for providing successive digital total signals indicative of the frequency spectrum and amplitude of speech at the instants of time denoted by the frames of digital words.

Claim 32

The synthesizer of claim 25, wherein said first means includes a table of amplitude modulated trigonometric functions and an adder and addressing means operatively associated with said second table and said first means for causing said second table to transmit digital data signals to said adder means.

Claim 33

A digital signal synthesizer receiving a bit stream input containing frames of frequency information bits and corresponding spectrum-segment amplitude information bits, comprising: means for generating sine data for the fundamental frequency represented by the frequency-information bits of a frame and each harmonic thereof to an upper limit for each of a plurality of successive time periods, said means for generating including means for generating harmonics of the fundamental frequency represented by a single frame of frequency information bits, means for comparing selected bandwidths with the generated harmonics, and means for generating an indexing signal each time a predetermined condition exists between a selected bandwidth and a generated harmonic; means for combining the sine data for the fundamental frequency and each of the harmonics thereof with the corresponding spectrum-segment amplitude information bits for each of the plurality of successive time periods to generate a plurality of data words individually representing a segment of an output signal; and means for combining the plurality of data words into a single synthesized signal.

Claim 34

A digital signal synthesizer receiving a bit stream input containing frames of frequency information bits and corresponding spectrum-segment amplitude information bits, comprising: means for generating sine data for the fundamental frequency represented by the frequency-information bits of a frame and each harmonic thereof to an upper limit for each of a plurality of successive time periods, said means for generating including means for generating harmonics of the fundamental frequency represented by a single frame of frequency information bits, means for comparing selected bandwidths with the generated harmonics, and means for generating an indexing signal each time a predetermined condition exists between a selected bandwidth and a generated harmonic; means for combining the sine data for the fundamental frequency and each of the harmonics thereof with the corresponding spectrum-segment amplitude information bits for each of the plurality of successive time periods to generate a plurality of data words individually representing a segment of an output signal; and means for combining the plurality of data words into a single synthesized signal.

Claim 35

A digital signal synthesizer as set forth in claim 27 wherein said means for generating an indexing signal includes means for generating a recycling pulse after the selected bandwidths have been compared with the generated harmonics.

Claim 36

A digital signal synthesizer as set forth in claim 28 including means for generating a bandwidth marker pulse at the completion of the comparison of the selected bandwidths with the generated harmonics to change the basis for the sine data generated for each successive time period of a frame.

Claim 37

A digital signal synthesizer as set forth in claim 29 including means for generating a timing pulse for each of the plurality of successive time periods.

Claim 38

A digital signal synthesizer as set forth in claim 30 wherein said means for generating sine data includes means responsive to the indexing signals for generating a memory address for a read-only-memory.

Claim 39

A digital signal synthesizer receiving a bit stream input containing frames of frequency information bits and corresponding spectrum-segment amplitude information bits, comprising: means for generating sine data for the fundamental frequency represented by the frequency information bits of a frame and each harmonic thereof up to an upper limit for each of a plurality of successive time periods; means for combining the sine data for the fundamental frequency and each of the harmonics thereof with the corresponding spectrum-segment amplitude information bits for each of the plurality of successive time periods to generate a plurality of data words individually representing a segment of an output signal, said means for combining including means responsive to the sine data and the amplitude information bits and operative to emit a digital signal indicative of a respective point of an amplitude modulated sine wave, and storage register means receiving the spectrum-segment amplitude information bits and operative to pass a predetermined segment of the information bits to said means responsive to the sine data; and means for combining the plurality of data words into a single synthesized signal.

Claim 40

A digital signal synthesizer receiving a bit stream input containing frames of frequency information bits and corresponding spectrum-segment amplitude information bits, comprising: means for generating sine data for the fundamental frequency represented by the frequency information bits of a frame and each harmonic thereof up to an upper limit for each of a plurality of successive time periods; means for combining the sine data for the fundamental frequency and each of the harmonics thereof with the corresponding spectrum-segment amplitude information bits for each of the plurality of successive time periods to generate a plurality of data words individually representing a segment of an output signal, said means for combining including means responsive to the sine data and the amplitude information bits and operative to emit a digital signal indicative of a respective point of an amplitude modulated sine wave, and storage register means receiving the spectrum-segment amplitude information bits and operative to pass a predetermined segment of the information bits to said means responsive to the sine data; and means for combining the plurality of data words into a single synthesized signal.

Claim 41

A digital signal synthesizer receiving a bit stream input containing frames of frequency information bits and corresponding spectrum-segment amplitude information bits, comprising: means for generating sine data for the fundamental frequency represented by frequency information bits of a frame and each harmonic thereof up to an upper limit for each of a plurality of successive time periods; means for combining the sine data for the fundamental frequency anD each of the harmonics thereof with the corresponding spectrum-segment amplitude information bits for each of the plurality of successive time periods to generate a plurality of data words individually representing a segment of an output signal, said means for combining including an adder for adding the latest data word with an accumulation of all previous data words for a given time period; and means for combining the plurality of data words into a single synthesized signal.

Claim 42

A digital signal synthesizer receiving a bit stream input containing frames of frequency information bits and corresponding spectrum-segment amplitude information bits, comprising: means for generating sine data for the fundamental frequency represented by frequency information bits of a frame and each harmonic thereof up to an upper limit for each of a plurality of successive time periods; means for combining the sine data for the fundamental frequency anD each of the harmonics thereof with the corresponding spectrum-segment amplitude information bits for each of the plurality of successive time periods to generate a plurality of data words individually representing a segment of an output signal, said means for combining including an adder for adding the latest data word with an accumulation of all previous data words for a given time period; and means for combining the plurality of data words into a single synthesized signal.

Claim 43

A digital signal synthesizer as set forth in claim 33 wherein said means for combining the plurality of data words includes a digital-to-analog converter for producing an analog synthesized signal

Claim 44

A digital signal synthesizer as set forth in claim 33 wherein said means for combining the plurality of data words includes means for scaling the accumulated total by a factor inversely proportional to the number of generated harmonics.

Claim 45

A digital voice synthesizer receiving a bit stream input containing frames of voice frequency information bits and corresponding spectrum-segment amplitude information bits along with frames of unvoiced frequency information bits and corresponding spectrum-segment amplitude information bits, comprising: means for generating sine data for a frequency represented by voice frequency information bits and each harmonic thereof up to an upper limit and unvoiced frequency information bits and each harmonic thereof up to an upper limit for each of a plurality of successive time periods in a given frame; means for combining the sine data for a fundamental and each harmonic thereof with corresponding spectrum-segment amplitude information bits for each of a plurality of successive time periods to generate a plurality of data words individually representing a segment of an output signal; means for randomly modifying the sine data generated for each frame of unvoiced frequency information bits prior to combining thereof with the corresponding spectrum-segment amplitude information bits, said means for randomly modified including a noise generator connected to said means for generating sine data and responsive to an ''''all-zero'''' series of frequency information bits; and means for combining the plurality of data words of a given frame into a single synthesized signal.

Claim 46

A digital voice synthesizer receiving a bit stream input containing frames of voice frequency information bits and corresponding spectrum-segment amplitude information bits along with frames of unvoiced frequency information bits and corresponding spectrum-segment amplitude information bits, comprising: means for generating sine data for a frequency represented by voice frequency information bits and each harmonic thereof up to an upper limit and unvoiced frequency information bits and each harmonic thereof up to an upper limit for each of a plurality of successive time periods in a given frame; means for combining the sine data for a fundamental and each harmonic thereof with corresponding spectrum-segment amplitude information bits for each of a plurality of successive time periods to generate a plurality of data words individually representing a segment of an output signal; means for randomly modifying the sine data generated for each frame of unvoiced frequency information bits prior to combining thereof with the corresponding spectrum-segment amplitude information bits, said means for randomly modified including a noise generator connected to said means for generating sine data and responsive to an ''''all-zero'''' series of frequency information bits; and means for combining the plurality of data words of a given frame into a single synthesized signal.

Claim 47

A digital voice synthesizer as set forth in claim 36 wherein said means for generating the sine data includes means for generating harmonics of the voiced fundamental frequency represented by a single frame of frequency information bits and for generating harmonics of a predetermined frequency and the harmonics thereof for the ''''all zero'''' unvoiced frame of frequency information bits.

Claim 50

A method of synthesizing a signal as set forth in claim 38 including the step of generating time pulses to establish each of the successive time periods.

Claim 51

A method of synthesizing a signal as set forth in claim 38 including the step of comparing selected bandwidths With the generated harmonics and producing an indexing signal each time a predetermined condition exists between a selected bandwidth and a generated harmonic.

Claim 54

A method of synthesizing a signal as set forth in claim 41 including the step of recycling the comparison of the selected bandwidths with the generated harmonics for each of the successive time periods.

Claim 55

A method of synthesizing a signal as set forth in claim 42 wherein the step of combining a sine data with the corresponding spectrum-segment amplitude information bits includes generating a digital signal indicative of a respective point on an amplitude-modulated sine wave.

Claim 56

Apparatus for generating synthesized signal from a digital input corresponding to a first signal, said digital input having a plurality of successively presented frames of digital words, and each frame including at least one word relating to a fundamental frequency and a plurality of words relating to the amplitude of the first signal, each amplitude word relating to at least one of a plurality of predetermined bands of harmonics, said signal synthesizer comprising: input means connected to receive said digital input for converting the same for use in the synthesizer; register means coupled to the input means for storing the amplitude words of a respective frame; first accumulator means coupled to the input means for generating preliminary sine words at a rate corresponding to the fundamental frequency of a respective frame; recognition means coupled to the accumulator means and the register means for producing a first output word for each preliminary sine word for which there is a corresponding word of amplitude data available in the register means, and wherein said first output words produce equal, respectively, the sine of the angle represented by the preliminary sine word times the amplitude word; second accumulator means for producing an output word corresponding to the summation of all words produced by the recognition means during a predetermined instant of time corresponding to a band of amplitude data and the magnitude of the fundamental frequency associated therewith; scaling means for balancing the value of the word produced by the accumulator means at one instant of time with respect to the value of the words produced at other instants of time; and output means coupled to the scaling means for converting the digital words produced for each instant of time to an analog voltage, such that the combined voltage produced in response to successive words from the output means comprises a synthesized signal. 45. Apparatus for generating a synthesized signal as set fortH in claim 44 including means for advancing the amplitude data words of each respective frame through the register means and for advancing the register means and the first and second accumulator means to the next frame upon the completion of the processing of a respective frame.