Abstract: A device and a method for estimating an open-loop pitch in a general speech CODEC are disclosed. The open-loop pitch estimation device includes an autocorrelation function calculation unit which calculates a normalized autocorrelation function from a perceptual weighing filtered speech signal, a maximum autocorrelation function and lag estimation unit which estimates a maximum autocorrelation function and candidates for the maximum autocorrelation function, a pitch candidate decision unit which decides candidates for a pitch by using the ratio of the estimated maximum autocorrelation function to the candidates for the estimated maximum autocorrelation function, and lags of which values are smaller than a predetermined threshold value, and a pitch estimation unit which estimates a pitch between the candidates for a pitch and the lags corresponding to the estimated maximum autocorrelation function by using a pitch of a previous frame of the speech signal.

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: A method and an apparatus for transmitting a speech signal are provided. A speech signal transmitter includes a quadrature mirror filter, a bas sub-band encoder, an enhancement sub-band encoder, and a network connector. The quadrature mirror filter receives a speech signal, divides the speech signal into an enhancement band speech signal and a base band speech signal, and outputs the enhancement band speech signal and the base band speech signal. The base sub-band encoder receives and encodes the base band speech signal. The enhancement sub-band encoder receives and encodes the enhancement band speech signal. The network connector multiplexes the encoded enhancement band speech signal and the encoded base band speech signal based on the kinds of networks over which speech signals are transmitted, and transmits the multiplexed signals to the networks. A speech signal is multiplexed and transmitted by various methods based on the kinds of networks. Thus, the speech signal can be efficiently transmitted.

Abstract: An Integrated Services Digital Network (ISDN) communications terminal apparatus is provided. The ISDN communications terminal apparatus includes a reset and clock signal unit for providing a reset signal and a clock signal needed by a communications service controller; a memory unit for storing a start program and an operating program of the communications terminal apparatus and user data; an input/output unit for receiving needed information from a user and providing needed information to the user; a transformer for matching a signal of ISDN lines or a network termination apparatus; and a communications service control unit which internally has a Reduced Instruction Set Computer (RISC) microprocessor, and is connected to the reset and clock signal unit, the memory unit, the input/output unit, and the transformer to process the communications protocol of each unit.

Abstract: A system for converting a heterogeneous compressed moving picture data, includes: a variable length decoder for generating variable length decoded data as first compressed moving picture data from a first data bit stream; a compressed moving picture data analyzer for analyzing layer types of the first compressed moving picture data; a layer-matching device for matching layers of the first compressed moving picture data to layers of second compressed moving picture data, thereby generating the second compressed moving picture data; and a variable length encoder for generating variable length coded data as a second data bit stream. Thereby, the system can convert an H.261 compressed moving picture data to an MPEG-1 compressed moving picture data on a compression domain.

Abstract: The present invention is to provide an improved efficiency of transmission and reception for data in an ATM SAR (Asynchronous Transfer Mode Segmentation and Reassembly) module for a xDSL communication service chip.

Abstract: An improved video window control apparatus and a method thereof which are capable of generating a plurality of video windows on a television or a computer monitor, controlling the size and position thereof, and providing a video window overlap function and a picture-in-picture function.

Abstract: The invention provides a method of multiplexing moving pictures fed from a plurality of multimedia communication terminals through broadband Integrated Service Distance Network (B-ISDN) and displaying a multiplexed moving picture on a display unit of the plurality of terminals, which comprising the steps of checking a type and a performance of the terminals, and assistance possible performance of the MCU to the terminals by end-and-end signaling; and selecting M terminals among the plurality of terminals connected thereto; generating a start signal to the selected M terminals, the start signal allowing each of the selected terminals to generate the moving picture to be processed; processing a first and second moving pictures generated from two terminals in response to the start signal; processing a third and four moving pictures generated from two terminals in response to the start signal; repeating said steps until all of moving pictures from the selected M terminals are inputted.