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| Number | Title | Issue Date |
| 4879748 | Parallel processing pitch detector A pitch detector system for use with speech analysis and synthesis methods having a plurality of identical detectors each responsive to a different portion of a speech signal for estimating a pitch value and a voter circuit responsive to the estimated pit... | 11/07/1989 |
| 4817155 | Method and apparatus for speech analysis Speech analysis is performed by synchronizing, with the initiation of glottal pulses produced during the voicing of phonemes, a pitch-independent transform that performs analysis entirely within a pitch period. Analysis is made of the three most dominant ... | 03/28/1989 |
| 4802221 | Digital system and method for compressing speech signals for storage and transmission The system and method of the invention operates upon a serial bit stream of speech encoded data by reading the data in fixed length frames. Each frame is classified as to whether the frame represents voiced, unvoiced, or a silence condition. For a voiced ... | 01/31/1989 |
| 4771465 | Digital speech sinusoidal vocoder with transmission of only subset of harmonics A speech analyzer and synthesizer system using a sinusoidal encoding and decoding technique for voiced frames and noise excitation or multipulse excitation for unvoiced frames. For voiced frames, the analyzer transmits the pitch, values for a subset of of... | 09/13/1988 |
| 4764966 | Method and apparatus for voice detection having adaptive sensitivity This invention enables voice energy to be distinguished from energy due to other sources such as telephone call progress signals. A portion of the audio spectrum is divided into a high and into a low frequency band and the energy content of these bands is... | 08/16/1988 |
| 4630300 | Front-end processor for narrowband transmission Bandwidth compression of speech signals is done by aliasing the fricativeund signals (4-8 KHz) into the voiced-sound signal band for transmission (0-4 KHz). To minimize distortion, aliasing (foldover) is done only when the fricative band power is more th... | 12/16/1986 |
| 4618982 | Digital speech processing system having reduced encoding bit requirements A digitized speech signal is divided into sections and each section is analyzed by the linear prediction method to determine the coefficients of a sound formation model, a sound volume parameter, information concerning voiced or unvoiced excitation and th... | 10/21/1986 |
| 4611342 | Digital voice compression having a digitally controlled AGC circuit and means for including the true gain in the compressed data An apparatus for use in transmitting compressed digital voice data includes an analyzer for compressing digitized voice data according to an algorithm which produces a root mean square of the voice data. An analog to digital converter is used to convert a... | 09/09/1986 |
| 4589131 | Voiced/unvoiced decision using sequential decisions Speech signal is decided voiced or unvoiced by a sequence of unilateral decisions: a first test decides "unvoiced" if standardized energy Es is below a threshold, or "ambiguous" if above the threshold whereby a second test decides "unvoiced" if... | 05/13/1986 |
| 4509186 | Method and apparatus for speech message recognition Speech recognition by first log-compressing the speech signal, then filtering into subband signals which are subtracted to form an indicator of voiced, unvoiced and silence intervals, whereby sequence and duration patterns are coded in +1, -1, and zero.... | 04/02/1985 |
| 4495620 | Transmitting data on the phase of speech The present invention relates to a means for achieving simultaneous transmission of data and speech with only a minimal expansion of the bandwidth of the speech signal. A Fourier transform (14) is performed on the speech signal and a predetermined number ... | 01/22/1985 |
| 4461024 | Input device for computer speech recognition system Systems for the recognition of speech by computer have usually required t the speech be of a strictly standarized nature, free of such features as regional accent, and unaccompanied by background noise. The problem has been to produce a system providing ... | 07/17/1984 |
| 4360708 | Speech processor having speech analyzer and synthesizer Adaptive bit allocation optimizes the encoded transmission of speech signal parameters. Allocation is controlled by a voiced/unvoiced decision signal derived from occurrence rate distributions of Partial Correlation Coefficient K1.... | 11/23/1982 |
| 4292469 | Voice pitch detector and display Voice pitch is detected by passing a speech signal from a microphone 10 through a filter array 20 to a summing amplifier 22. The summing amplifier 22 provides a composite signal of the acoustic components of the speech signal and this composite signal is ... | 09/29/1981 |
| 4281218 | Speech-nonspeech detector-classifier The classification of a signal on a telephone line can be based on its short term average energy level; nonspeech (data or signalling) as high level; speech as medium level, and noise as low level. A common use for speech detectors occurs with a time assi... | 07/28/1981 |
| 4230906 | Speech digitizer A speech digitizer is disclosed including an analyzer for generating power and filter coefficient parameters representative of an analog speech waveform. The digitizer also includes a pitch detector for generating a digital pitch parameter substantially r... | 10/28/1980 |
| 4170719 | Speech transmission system A speech transmission system is improved in intelligibility and naturalness by separating voiced from invoiced speech segments prior to application to a transmission channel of restricted bandwidth. Voiced segments are combined without processing with dis... | 10/09/1979 |
| 4164626 | Pitch detector and method thereof A pitch and voiced/unvoiced detector comprising a low pass filter or variable cutoff frequency low pass filter for providing a constant power output, DC shifting and weighting circuits operating on the filtered analog signals, a summing circuit for the fi... | 08/14/1979 |
| 4158751 | Analog speech encoder and decoder Described herein are analog speech encoder and decoder systems using a plurality of narrow band pass filters with associated rectifiers and ripple filters for spectrum analyzing the speech or other suitable signals, and a corresponding plurality of narrow... | 06/19/1979 |
| 4110560 | Communication apparatus A half-duplex digitally-controlled telephone communication apparatus for permitting half-duplex communication between local and remote subscribers. Analog speech of one subscriber to be transmitted to the other subscriber is converted to a digital format,... | 08/29/1978 |
| 4074069 | Method and apparatus for judging voiced and unvoiced conditions of speech signal The voiced and unvoiced conditions of a speech signal are judged by combining a ratio (defined as the parcor coefficient k1) $c;(͌s)/$c;(o) between the value $c;(o) of the autocorrelation function of the speech signal at a zero delay ... | 02/14/1978 |
| 4058676 | Speech analysis and synthesis system Method and apparatus for speech analysis and synthesis adapted for analyzing and multiplexing speech signals from a plurality of voice grade telephone lines for further transmission through a single voice grade telephone line. A plurality of specialized d... | 11/15/1977 |
| 4044204 | Device for separating the voiced and unvoiced portions of speech A speech signal-in-noise enhancement system which separates the voiced-unvoiced portions of speech, detects and extracts the voiced fundamental pitch and uses that data to control the band-pass center frequencies of a bank of filters so that the filters p... | 08/23/1977 |
| 4015088 | Real-time speech analyzer Apparatus for the real-time analysis of speech signals in which a digital signal representative of the speech signal is adaptive threshold center-clipped and infinite peak-clipped to form a signal comprising three logic states (+1,0,-1). The autocorrelati... | 03/29/1977 |
| 3975587 | Digital vocoder This invention relates to a digital vocoder where speech is translated to a digital version thereof. An adaptive filter in the form of an N stage Itakura type cascade derives from the speech a prediction residual and N spectral parameter in the form of we... | 08/17/1976 |
