Electronics and Telecommunications Research Institute

JongMo Sung

Do-Young Kim

Hyun-Woo Kim

Bong Tae Kim

Do Young Kim

Mi-Suk Lee

Sang Taick Park

Young-Sun Kim

Provides is an embedded code-excited linear prediction speech coding/decoding apparatus and method that can deal with the capacity change of speech transmission channel by modeling an error signal not coded at a core speech coder based on a transmission rate in a multiple pulse search mode or gain compensation mode and then transmitting it in an optimum mode. The apparatus includes a core speech coding unit for coding an input speech signal with spectral envelop and an excitation signal, a transmission rate determination unit for allocating the number of bits additionally allowed depending on a capacity of a transmission channel, and an embedded excitation signal coding unit for coding a residual excitation signal that is not coded in the core speech coding unit based on the number of additionally allowed bits using one of a multiple pulse excitation coding mode and a gain compensation mode.

Embedded code-excited linear prediction speech coding and decoding apparatus and method

A caller identification system provides a caller identifier of an actual user rather than the conventional telephone number dependent on a caller terminal. Further, a caller base billing method and its system can bill an actual user by carrying out user authentication through a certification authority for a caller identifier that is independent of a caller terminal. The method includes the steps of receiving authentication information of the caller from a caller terminal; verifying the authentication information; and carrying out call setup if the authentication information and the certificate match, wherein the authentication information is generated by using a caller identifier and a private key that are applied by the caller, with no dependency on the caller terminal, and caller information corresponding to the caller identifier is transmitted to a callee terminal during call setup.

Caller identification method, and billing system and method using the same in internet telephony

The present invention overcomes problems of tandem coding method such as degradation of speech quality, increased system latency and computations. An apparatus for trans-coding between code excited linear prediction (CELP) type codecs with different bandwidths, includes: a format parameter translating unit for generating output formant parameters by translating formant parameters from input CELP format to output CELP format; a formant parameter quantizing unit for receiving the output format formant parameters and quantizing the output format formant filter coefficients; an excited parameter translating unit for generating output excitation parameters by translating excitation parameters from input CELP format to output CELP format; and an excitation quantizing unit for receiving the output format excitation parameters and quantizing the output format excitation parameters.

Apparatus and method for transcoding between CELP type codecs having different bandwidths

An apparatus for concealing a highband error in a spilt-band wideband voice codec in accordance with the present invention is disclosed. The apparatus includes: a lowband LPC coefficient extracting unit for extracting a lowband linear predictive coding (LPC) coefficient from a lowband voice signal passed by a lowband decoding unit; a highband excitation signal generating unit for generating a highband excitation signal based on the lowband voice signal and the lowband LPC coefficient; a highband LPC coefficient generating unit for generating a highband LPC coefficient based on the lowband LPC coefficient; a highband voice synthesizing unit for synthesizing a highband voice signal based on the highband excitation signal and the highband LPC coefficient; and a high pass filtering unit for removing a lowband component of the synthesized highband voice signal by the highband voice synthesis unit and generating the synthesized highband voice signal.

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Daejon, South Korea

JongMo Sung