Abstract: A pitch determiner (414) for use with a speech analyzer includes a pitch function generator (414) which generates a plurality of pitch components representing a pitch function for one or more sequential segments of speech. which are represented by a predetermined number of digitized speech samples. A pitch enhancer (1116) enhances the pitch function of a current segment of speech utilizing the pitch function of one or more sequential segments of speech to generate a plurality of enhanced pitch components. A pitch detector (1118) detects the pitch of the current segment of speech by determining the pitch of an enhanced pitch component having a largest amplitude of the plurality of enhanced pitch components.

Abstract: An MBE synthesizer (116) for generating a segment of speech from compressed speech data received by a receiver (2004). The compressed speech data includes one or more indexes (2240, 2242) and pitch data (2248). The MBE synthesizer (116) includes the following: an excitation generator (2222) utilizing a transform function for generating transformed excitation components responsive to the pitch data (2248). A memory (3006) for storing a table of predetermined spectral vectors (2205) and associated predetermined voicing vectors (2203). A harmonic amplitude estimator (2209) that is responsive to the one or more predetermined spectra/vectors identified by the indexes (2240, 2242) received, that generates harmonic amplitude control signals. The harmonic amplitude estimator (2209) which includes a peak detector (2503), a peak enhancer (2505), a valley detector (2507), a valley enhancer (2509).

Abstract: A method and apparatus is provided for a low bit rate speech transmission. Speech spectral parameter vectors are generated from a voice message and stored in a sequence of speech spectral parameter vectors within a speech spectral parameter matrix. A first index identifying a first speech parameter template corresponding to a first speech spectral parameter vector of the sequence of speech spectral parameter vectors is transmitted. A subsequent speech spectral parameter vector of the sequence is selected and a subsequent speech parameter template is determined having a subsequent index. One or more intervening interpolated speech parameter templates are interpolated between the first speech parameter template and the subsequent speech parameter template. The one or more intervening speech spectral parameter vectors are compared to the corresponding one or more intervening interpolated speech parameter templates to derive a distance.

Abstract: An apparatus codes excitation parameters for very low bit rate voice messaging using a method that processes a voice message to generating speech parameters. The speech parameters are separated (316) to produce a first group of energy parameters and a second group of pitch and voicing parameters. Subsequently, the first group of energy parameters are encoded and compressed using a non-uniform root-mean-square scalar process (318) to create a first plurality of encoded data. Additionally, the second group of pitch and voicing parameters are compressed, encoded, and combined into a single parameter using a three slope vector encoding process (320) that creates a second plurality of encoded data. Finally, the first and second plurality of encoded data are multiplexed (322) to create a multiplexed signal for transmission, the multiplexed signal representing the voice message.

Abstract: Error detection and correction of a received message, such as a digitized voice message is achieved by generating (318) interpolated vectors for each error vector corresponding to a codebook index in a sequence of codebook indexes representing parameters of portions of the message. A plurality of error corrected candidate vectors for the vector corresponding to the codebook index in error, are generated (322,324,326) by flipping one bit in a sequence of bits representing the codebook index in error. The error corrected candidate vector which has a minimal difference from its corresponding interpolated vector is used (338) to replace the error vector. In the case of digital voice, the vectors are spectral vectors which represent spectral information for a time sample of a voice message. An ordering property of vector components is exploited to detect errors in a received codebook index without parity bits.

Abstract: A method of locating a portable communication unit (108) having a transmitter (852) for transmitting acknowledge back signals, consists of the steps of transmitting, to the portable communication unit (108) from the communication cell transmitters (104), an information signal which consists of a predetermined color code word which identifies a subset of the communication cells (500) for which radio coverage does not overlap; receiving an acknowledge back signal from the portable communication unit (108) consisting of a reported color code value determined from the color code word transmitted in the information signal; and analyzing the reported color code value to determine a cell location of the portable communication unit (108).