Motorola Corporation

Kenneth D Finlon

Floyd D Simpson

Jian-Cheng Huang

Sunil Satyamurti

Arthur Gerald Herkert

Robert J Schwendeman

Lu Chang

James Michael Keba

Oleg Andric

Yan-Ming Cheng

A system controller ( ) is for transferring a low bit rate digital voice message. The system controller generates from an analog voice signal representing the voice message a set of speech model parameters, and generates a first derived set of speech model parameters from a first subset of the set of speech model parameters, the first derived set encoding the voice signal at a second voice quality and second vocoder rate that are less, respectively, than a first voice quality and vocoder rate. The system controller transmits ( ) the low bit rate-digital voice message comprising the first derived set of speech model parameters to a communication receiver ( ). The communication receiver requests ( ) an incremental message when the quality of the voice message is unsatisfactory. The system controller generates and transmits ( ) an incremental message-and the communication receiver uses ( ) the incremental message to generate a higher quality voice message.

Method and apparatus for transferring low bit rate digital voice messages using incremental messages

A digital signal processor for processing data including voice messaging data that may have both voiced and unvoiced speech components utilizes computer routines stored in a memory used by the digital signal processor. The computer routines programmed provide for control of at least a portion of a selective call receiver; receiving and decoding data received at the selective call receiver; comparing the addresses received at the selective call receiver with addresses stored in a memory location coupled to the digital signal processor; controlling voicing including both voiced and unvoiced speech components; and generating a pitch wave using an inverse discrete Fourier Transform and resample the pitch wave to provide a time domain voiced speech component.

Digital signal processor for processing voice messages

A system controller ( ) includes a speech encoder ( ) that encodes a low bit rate digital voice message. The speech encoder sets values of words of a header of the encoded message. The values of the words define a quantity of frames in the voice message, N, and define a vocoder rate used for the encoded message. The speech encoder sets a state of each indicator in each frame status field of N frame status fields that are transmitted after the header of the encoded message. The speech encoder assembles N frame data fields, wherein each of the frame data fields comprises a set of data words. The N frame data fields follow the N frame status fields. Each set of data words conforms to at least one of the vocoder rate and the states of the indicators. A decoder ( ) decodes the encoded low bit rate digital message.

Method and apparatus for encoding and decoding frames of voice model parameters into a low bit rate digital voice message

A system controller ( ) includes a speech encoder ( ) that dynamically segments frames of a low bit rate digital voice message. Speech model parameters have been generated in a sequence of frames. The speech model parameters include quantized speech spectral parameter vectors. The speech encoder selects ( ) a first quantized speech spectral parameter vector as a current anchor vector, selects ( ) a second quantized speech spectral parameter vector located a predetermined number of frames (L ) from the current anchor vector as a target speech parameter vector, and perturbs ( ) the target speech parameter vector to derive a plurality (K) of perturbed speech parameter vectors.

Method and apparatus for dynamic segmentation of a low bit rate digital voice message

A pitch determiner ( ) of a system controller ( ) that generates a smoothed pitch value for a current frame of a low bit rate voice message includes a pitch function generator ( ) that generates a pitch detection function (PDF) for each frame of digital samples of a voice signal, a pitch candidate selector ( ) that selects a future frame pitch candidate from a pitch detection function (PDF), and a pitch adjuster ( ) that generates the smoothed pitch value. The pitch adjuster includes a subharmonic pitch corrector ( ) that determines a future frame pitch value by performing pitch subharmonic correction of a future frame pitch candidate using a roughness factor of the frequency transformed window.

Method and apparatus for pitch determination of a low bit rate digital voice message

A technique is used in a speech encoder ( ) that reduces non-speech activity of a low bit rate digital voice message. Speech model parameters that include quantized speech spectral parameter vectors are generated in a sequence of frames. A determination is made as to which frames of the sequence of frames are voiced frames and which frames are unvoiced frames. A consecutive sequence of frames of unvoiced frames is identified ( ) as an unvoiced burst when a length, N , of the consecutive sequence of frames exceeds a predetermined length, N . A non-speech activity portion of the unvoiced burst is identified ( ) and removed.

Method and apparatus for non-speech activity reduction of a low bit rate digital voice message

A radio communication system includes a voice recognition system (218), a transmitter (202) and a processing system (210). The voice recognition system is utilized for receiving caller initiated messages, and the transmitter is used for transmitting messages to a plurality of SCRs (selective call radios) (122) of the radio communication system. The processing system, which is coupled to the voice recognition system, and the transmitter, is adapted to cause the voice recognition system to convert a voice signal representative of a voice message originated by a caller of the radio communication system to a text message (401, 417), wherein the text message is intended for a SCR, to then generate a likelihood of success that the voice signal has been flawlessly converted to a text message, to have a human listen to an audible representation of the voice signal, and to cause the transmitter to transmit the text message to the SCR (432). The converting step includes autocorrelation by Fourier transform, measure a degree of voiceness for each band, applying the degree of voiceness to a corresponding plurality of phenome models, and deriving a text equivalent by searching through a phenome library.

Automatic and attendant speech to text conversion in a selective call

A MBE synthesizer (2200) for generating speech from information received by a receiver (114) includes a voiced signal generator (2280) for generating voiced signal components in the time domain using an IDFT in a pitch wave generator (2210) and and a pitch wave resampler (2232) and an unvoiced signal generator (2290) for generating unvoiced signal components in the time domain. The MBE synthesizer also includes a voicing processor (2218) responsive to band voicing flags within the excitation information for controlling selection of a voiced spectral component or an unvoiced spectral component from a harmonic amplitude spectrum.

Low complexity MBE synthesizer for very low bit rate voice messaging

A communication system providing selective encoding of digital messages (408) comprising a plurality of transmitting devices (116) and a plurality of receiving devices (122). The transmitting devices (116) transmit an encoded address (404), encoded message vector (406) in a first portion of the message, and digital message (408) in a second portion of the message. The digital message (408) is encoded in the second portion of the message with an error correction code if the digital message is a data message (414), and without the overhead of an error correction code if the digital message (408) is a voice message (410). The receiving device (122) decodes the encoded address (404), encoded message vector (406), and digital message (408) transmitted by the transmitting devices (116) in the first and second portion of the message. The receiving device (122) determines the encoding method of the digital message (408) based on the message type received in the message vector (406), and thereafter decodes the digital message.

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Wellington, FL, United States of America

Kenneth D Finlon