Abstract:
본 발명은 음성신호 처리에 관한 것으로 특히 광대역 음성 신호의 부호화기에 관한 것이며 보다 상세하게는 광대역 저전송률 음성 신호의 부호화기에 관한 것으로, 고주파수로 샘플링된 음성 신호 프레임을 저주파수로 다운 샘플링 한 후, DC성분이 제거된 음성 신호 프레임을 생성하는 전처리 및 다운샘플링 블록; 상기 다운 샘플링된 음성 신호 프레임을 입력받아 상기 프레임의 선형 예측 계수를 구하고 이 계수를 ISP로 변환하여 양자화 시키며 상기 ISP의 인덱스를 생성하는 LPC분석 및 ISP양자화 블록; 상기 다운 샘플링된 음성 신호의 합성 필터의 여기 신호를 모델링하기 위한 잔차 신호를 산출하는 잔차신호 계산 블록; 상기 여기 신호의 모델링을 위한 랜덤벡터를 발생시키는 랜덤벡터 발생 블록; 상기 랜덤벡터를 스케일링하기 위한 이득을 산출하는 이득계산 블록; 및 상기 이득을 양자화하고, 상기 이득의 인덱스를 생성하는 이득 양자화 블록을 포함한다.
Abstract:
PURPOSE: A vocoder and a voice coding method using the vocoder are provided to reduce the quantity of calculations required for fixed codebook search for innovation analysis and decrease the number of memories and bits used for the fixed codebook search. CONSTITUTION: A vocoder includes a pre-processor for pre-processing an input voice signal, a linear predictive coding analysis and quantization unit for carrying out linear predictive coding analysis and quantization for the pre-processed signal, a pitch analyzer for analyzing a pitch to obtain long-section correlation, and a codebook searching unit for searching an algebraic codebook to model an innovation signal. The vocoder further includes a synthesis filter for synthesizing a speech signal using the pitch and code vector searched by the pitch analyzer and the codebook searching unit and a linear predictive coding coefficient output from the linear predictive coding analysis and quantization unit, an adder for calculating an error between the outputs of the pre-processor and the synthesis filter, a weight filter for receiving the error obtained by the adder to output a weight error, and a parameter encoder for encoding the linear predictive coding coefficient, a pitch parameter selected by the pitch analyzer and a codebook parameter selected by the codebook searching unit to output encoded voice data.
Abstract:
PURPOSE: An LSF(Line Spectral Frequency) coefficient vector quantizer for broadband voice coding is provided to reduce memory capacity and the quantity of calculations required for quantization and prevent the deterioration of the performance of the quantizer. CONSTITUTION: An LSF coefficient vector quantizer includes a prediction quantizer(30), an non-prediction quantizer(31), and a switch(32). The prediction quantizer includes the first vector quantizer(VQ1) for non-structurally quantizing an LSF coefficient vector to produce a candidate vector to be quantized, a predictor for calculating a predicted LSF vector of the LSF coefficient vector, and the first lattice quantizer for lattice-quantizing the candidate vector with reference to the predicted LSF vector to produce a final prediction quantization vector of the LSF coefficient vector. The non-prediction quantizer includes the second vector quantizer(VQ2) for non-structurally quantizing the LSF coefficient vector to produce a candidate vector to be quantized, and the second lattice quantizer for lattice-quantizing the candidate vector to produce a final non-prediction quantization vector of the LSF coefficient vector. The switch decides one of the final prediction quantization vector and the final non-prediction quantization vector, which has smaller difference from the LSF coefficient vector as a final quantization vector of the LSF coefficient vector.
Abstract:
PURPOSE: An Internet phone system and a method for operating the same are provided to use various codecs, to eliminate a voice delay with the optimum configuration and control of a voice buffer, to achieve home networking, to generate various tones, to minimize network loads, and to embody a rapid and stable Internet phone. CONSTITUTION: An Internet phone system is comprised of a home PNA transceiver part(111), an ethernet transceiver part(112), a MAC(Media Access Controller) part(109), a G.729/G.723 software codec part(102), a VoIP_IF part(105), and a G.711 codec part(113). The home PNA transceiver part(111) covers home networking in a physical layer. The ethernet transceiver part(112) covers ethernet connection in the physical layer. The MAC part(109) takes charge of access control with the Internet. The G.729/G.723 software codec part(102) executes a compression/decompression function for voice data inputted through the home PNA transceiver part(111) or the ethernet transceiver part(112). The VoIP_IF part(105) covers a function to process the voice data compressed or decompressed by the G.729/G.723 software codec part(102). The G.711 codec part(113) executes A/D conversion, D/A conversion or A/y-law PCM conversion for tones or voice data.
Abstract:
PURPOSE: A high-speed pitch searching method in a voiced sound section is provided to perform search only around a pitch of a prior frame, if a frame decided as a voiced sound is continued in a voice coder, so as to reduce calculation through the variation of the pitch. CONSTITUTION: A voice codec of a voice coder is initialized(201). If a voice signal of one frame is inputted(202), VAD(Voice Activity Detection) by the frame is performed(203). If the VAD is completed, information on the activity of the current frame and information on a pitch of a prior frame are used to decide a pitch search mode(204,205). The voice signal is coded using the decided pitch search mode(206), and the voice activity and pitch data of the current frame are stored by the coded information(207). Whether the current voice signal is a final signal is decided(208). If so, the steps are ended, and if not, the step of 202 is returned.
Abstract:
본 발명은 음성신호를 전송하는 방법 및 그 장치에 관한 것으로, 본 발명에 따른 음성신호 전송장치는 음성신호를 입력받아 고대역 신호와 저대역 신호로 분리하여 출력하는 직교반사필터부, 상기 저대역 신호를 입력받아 부호화하는 저대역부호화부, 상기 고대역 신호를 입력받아 부호화하는 고대역부호화부 및 음성신호가 전송될 통신망의 종류에 따라서 상기 부호화된 고대역 신호 및 저대역 신호를 다중화하여 상기 통신망으로 전송하는 통신망 접속부를 포함하는 것을 특징으로 한다. 본 발명에 따르면 제공되는 통신망의 종류에 따라서 다양하게 음성신호를 다중화 시켜 전달하게 되므로 효율적으로 음성신호를 전송할 수 있게되는 효과가 있다.
Abstract:
The present invention relates to a transmitter and a receiver for speech coding and decoding by using an additional bit allocation method. The transmitter and the receiver according to the present invention realize a voice communication service of high quality by using additional bits permitted in system requirements while using a conventional speech coder as it is. In addition, the transmitter and the receiver according to the present invention have an advantage in that they enable insertion of additional quantization blocks while not changing the structure of the conventional standard speech coder, since they allocate additional bits by applying a multi-stage quantization procedure not in a speech signal domain but in a parameter domain.
Abstract:
PURPOSE: A wideband voice encoder, a method therefor, a wideband decoder and a method therefor are provided to offer excellent voice quality in a voice interval which is not processed by an algebraical codebook by performing multi-stage fixed codebook retrieval. CONSTITUTION: A voice characteristic classifying unit(105) classifies the characteristic of a voice corresponding to a current frame using an open-loop pitch value of a recognition weight filtered signal of a wideband voice signal and a linear prediction factor by a statistical method. An adaptive codebook retrieving unit(106) retrieves a pitch delay value near the open-loop pitch value, calculates a pitch gain value, and generates an adaptive codebook contribution signal. The adaptive codebook retrieving unit outputs difference between the generated adaptive codebook contribution signal and the recognition weight filtered signal as a primary fixed codebook target signal. A primary fixed codebook retrieving unit(107) obtains a primary fixed codebook index and a primary fixed codebook gain value, generates a primary fixed codebook contribution signal corresponding to the obtained primary fixed codebook index. The primary fixed codebook retrieving unit outputs different between the generated primary fixed codebook contribution signal and the primary fixed codebook target signal as a secondary codebook target signal. A secondary fixed codebook retrieving unit(108) has at least two or more fixed codebooks according to voice characteristics, selects one secondary fixed codebook according to voice characteristic information, and retrieves secondary fixed codebook indexes and secondary fixed codebook gain values according to the voice characteristics. A parameter multiplexing unit(110) multiplexes voice characteristic information, the pitch delay value, the pitch gain value, the primary fixed codebook index, the primary fixed codebook gain value, the secondary fixed codebook indexes and the secondary fixed codebook gain values, generates a bit stream, and transmits the bit stream to an external voice decoding terminal.
Abstract:
PURPOSE: An apparatus and a method for transmitting/receiving a wideband voice signal are provided to offer high sound quality 16 kHz sampled wideband voice signal and compatibility with an existing system. CONSTITUTION: A analyzing/filtering unit(301) receives a digital voice signal and outputs a low band voice signal having a bandwidth of 0-4 kHz of 8 kHz sampling period. A low band standard coding unit(302) receives the low band voice signal, codes it and outputs a coded low band standard signal. A low band additional coding unit(304) receives a difference between a filtered low band voice signal and a composite signal that has been decoded by a low band standard decoding unit(303) and codes them to generate a low band additional signal. An enhancement residual band coding unit(306) up-samples a composite signal obtained by combining signals outputted from the low band standard decoding unit(303) and the low band additional decoding unit(305), obtains a difference between the up-sampled signal and a voice signal inputted to the analyzing/filtering unit(301), and generates an enhancement residual band signal.
Abstract:
광대역 음성 부호화기 및 그 방법과 광대역 음성 복호화기 및 그 방법이 개시된다. 본 발명에 따른 광대역 음성 부호화기는 부호화할 광대역 음성신호의 개회로 피치값과 선형예측계수를 이용하여 현재 프레임에 해당하는 음성의 특성을 규정하는 음성 특성 분류부, 적응 코드북을 검색하여 적응 코드북 피치 지연값 및 적응 코드북 피치 이득값을 얻고, 1차 고정 코드북 목적신호를 생성하는 적응 코드북 검색부, 1차 고정 코드북을 검색하여 1차 고정 코드북 인덱스와 1차 고정 코드북 이득값을 얻고, 2차 고정 코드북 목적신호를 생성하는 1차 고정 코드북 검색부, 음성 특성에 따라 적어도 둘 이상의 2차 고정 코드북들을 구비하며, 음성 특성 정보에 따라 하나의 2차 고정 코드북을 선택 및 검색하여 2차 고정 코드북 인덱스들과 2차 고정 코드북 이득값들 검색하는 2차 고정코드북 검색부 및 각 부에서 얻어지는 파라미터들을 양자화 및 다중화하여 비트열로 만들어 외부의 음성 복호화단으로 전송하는 파라미터 다중화부를 포함하는 것을 특징으로 하며, 음성 특성에 따라 2개 이상으로 구성된 2차 고정 코드북들로부터 음성 특성에 적합한 2차 고정 코드북을 선택함으로써 광대역 음성신호에 대해 보다 우수한 음질을 제공할 수 있다.