Abstract 937,434. Secret transmission. NIPPON ELECTRIC CO. Ltd. Feb. 19, 1960 [Feb. 24, 1959], No. 5941/60. Class 40 (4). Vowel synthesis apparatus has a plurality of similar circuits equal in number to the number of formants in the vowels to be synthesized. Input terminals a 1 , a 2 , a 3 , Fig. 1, receive signals representing the centre frequencies F 1 , F 2 , F 3 of the first, second and third formants, respectively, while input terminals b 1 , b 2 , b 3 receive signals representing the amplitudes of the formants at their respective centre frequencies and an input terminal c receives a signal representing the pitch of the vowel. By " centre frequency " is meant the frequency which has the maximum energy in the formant spectrum. For synthesis of the first formant, a wave generator 1 is excited by the signal at the input a 1 to produce oscillations of frequency f 1 + F 1 where f 1 is a constant characteristic of the generator. These oscillations are modulated in a balanced modulator 2 with signals generated in a harmonic generator 3, such signals consisting of the pitch frequency and higher harmonics of the pitch frequency. An amplitude shaping filter 4 is interposed between the generator 3 and modulator 2. This may have low pass or band pass characteristics. The output from the modulator 2 is applied to an equalizer 5 having an attenuation characteristic, Fig. 3, to provide attenuated output waves having a wave envelope of similar shape to the wave envelope of the formant but extending over a different frequency range from that of the formant. The equalizer has minimum attenuation at frequency f 1 . Its output is applied to a demodulator 6 for demodulation by the signal of frequency f 1 + F 1 from generator 1. After passage through a filter 7 the signal, now a vowel formant, is applied to an amplifier 8, the gain of which is controlled by the signal from input terminal b. Amplifiers 81 and 8<SP>11</SP> receive the other vowel formants in a similar manner and the outputs of all three amplifiers are fed to a mixer 9. In a modification the output of wave generator 1 is f 1 -F 1 .
Inventors
👤 Nagata Kuniichi
👤 Obara Kiyoshi
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-26 11:26
CPC Classifications
G; G10; G10L; G10L25/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
163 words
A DEVICE FOR SYNTHESIZING VOWELS FROM SIGNALS REPRESENTATIVE OF THE PITCH AND FORMANTS CHARACTERISTICS COMPRISING: MEANS FOR GENERATING HIGHER HARMONICS OF THE PITCH, IN RESPONSE TO A SIGNAL REPRESENTATIVE OF THE PITCH; A PLURALITY OF CIRCUITS EQUAL IN NUMBER TO THE PREDETERMINED NUMBER OF FORMANTS TO BE UTILIZED, EACH CIRCUIT COMPRISING A VARIABLE FREQUENCY OSCILLATOR FOR GENERATING IN RESPONSE TO A SIGNAL REPRESENTATIVE OF A FORMANT CENTER FREQUENCY, A HIGHER PREDETERMINED FREQUENCY PLUS OR MINUS SAID CENTER FREQUENCY, MEANS CONNECTED TO SAID VARIABLE FREQUENCY OSCILLATOR AND SAID HARMONICS GENERATING MEANS FOR AMPLITUDE MODULATING THE OSCILLATION WITH SELECTED OF SAID HARMONICS, AN EQUALIZER HAVING A FIXED CENTER FREQUENCY EQUAL TO SAID PREDETERMINED FREQUENCY AND FIXED FREQUENCY ATTENUATING CHARACTERISTICS PROPORTIONAL TO A FORMANT, CONNECTED TO SAID MODULATOR, AND MEANS CONNECTED TO SAID EQUALIZER AND SAID OSCILLATOR FOR DEMODULATING THE ATTENUATED OUTPUT OF SAID EQUALIZER; AND A MIXER COUPLED TO THE DEMODULATING MEANS OF ALL SAID CIRCUITS FOR ADDING THE OUTPUTS THEREOF TO FORM THE VOWEL.
Claim 2
Independent Claim
163 words
A DEVICE FOR SYNTHESIZING VOWELS FROM SIGNALS REPRESENTATIVE OF THE PITCH AND FORMANTS CHARACTERISTICS COMPRISING: MEANS FOR GENERATING HIGHER HARMONICS OF THE PITCH, IN RESPONSE TO A SIGNAL REPRESENTATIVE OF THE PITCH; A PLURALITY OF CIRCUITS EQUAL IN NUMBER TO THE PREDETERMINED NUMBER OF FORMANTS TO BE UTILIZED, EACH CIRCUIT COMPRISING A VARIABLE FREQUENCY OSCILLATOR FOR GENERATING IN RESPONSE TO A SIGNAL REPRESENTATIVE OF A FORMANT CENTER FREQUENCY, A HIGHER PREDETERMINED FREQUENCY PLUS OR MINUS SAID CENTER FREQUENCY, MEANS CONNECTED TO SAID VARIABLE FREQUENCY OSCILLATOR AND SAID HARMONICS GENERATING MEANS FOR AMPLITUDE MODULATING THE OSCILLATION WITH SELECTED OF SAID HARMONICS, AN EQUALIZER HAVING A FIXED CENTER FREQUENCY EQUAL TO SAID PREDETERMINED FREQUENCY AND FIXED FREQUENCY ATTENUATING CHARACTERISTICS PROPORTIONAL TO A FORMANT, CONNECTED TO SAID MODULATOR, AND MEANS CONNECTED TO SAID EQUALIZER AND SAID OSCILLATOR FOR DEMODULATING THE ATTENUATED OUTPUT OF SAID EQUALIZER; AND A MIXER COUPLED TO THE DEMODULATING MEANS OF ALL SAID CIRCUITS FOR ADDING THE OUTPUTS THEREOF TO FORM THE VOWEL.