Abstract: A method is provided. The method includes obtaining a low-band spectrum of an audio signal in which a low-band signal is frequency transformed; obtaining phase information of a high-band spectrum of the audio signal based on the low-band spectrum; and outputting a bitstream that comprises the phase information of the high-band spectrum.

Abstract: A Unified Speech and Audio Codec (USAC) that may process a window sequence based on mode switching is provided. The USAC may perform encoding or decoding by overlapping between frames based on a folding point when mode switching occurs. The USAC may process different window sequences for each situation to perform encoding or decoding, and thereby may improve a coding efficiency.

Abstract: A Unified Speech and Audio Codec (USAC) that may process a window sequence based on mode switching is provided. The USAC may perform encoding or decoding by overlapping between frames based on a folding point when mode switching occurs. The USAC may process different window sequences for each situation to perform encoding or decoding, and thereby may improve a coding efficiency.

Abstract: Provided are an apparatus for multi-stage transforming a plurality of unit blocks in multi-dimension that can improve compression efficiency of video data by collecting Discrete Cosine Transforming (DCT) coefficients of neighboring blocks and performing an additional transformation based on the DCT coefficients of an original picture and a differential picture. The method includes the steps of: performing a Discrete Cosine Transform (DCT) on inputted picture data and selecting R blocks of a predetermined size from DCT picture data, where R is a natural number equal to or greater than 2; arranging DCT coefficients of each of the selected R blocks according to each frequency in one-dimension; and performing one-dimensional transformation again on the DCT coefficients arranged in one-dimension.

Abstract: A speech compression apparatus including: a first band-transform unit transforming a wideband speech signal to a narrowband low-band speech signal; a narrowband speech compressor compressing the narrowband low-band speech signal and outputting a result of the compressing as a low-band speech packet; a decompression unit decompressing the low-band speech packet and obtaining a decompressed wideband low-band speech signal; an error detection unit detecting an error signal that corresponds to a difference between the wideband speech signal and the decompressed wideband low-band speech signal; and a high-band speech compression unit compressing the error signal and a high-band speech signal of the wideband speech signal and outputting the result of the compressing as a high-band speech packet.

Abstract: An apparatus and method for recovering lost voice packets are provided, in which a packet loss detector determines whether a received packet has been lost, packet information storage stores voice information of previous voice packets and voice information of the received voice packet, a packet error corrector measures the voice information of the received voice packet, stores the measured voice information in the packet information storage, corrects the voice information when necessary, and generates a corrected voice packet, if the received voice packet is normal, and a packet loss recoverer recovers the voice information of the received voice packet using the voice information of previous voice packets stored in the packet information storage and generates a recovered voice packet, if the received voice packet has been lost.

Abstract: An apparatus to compress a wide-band speech signal, the apparatus including a narrow-band speech compressor to compress a low-band speech signal of the wide-band speech signal and output the compressed low-band speech signal as a low-band speech packet; and a high-band speech compressor to compress a high-band speech signal of the wide-band speech signal using energy information of the low-band speech signal provided from the narrow-band speech compressor, and outputs the compressed high-band speech signal as a high-band speech packet.

Abstract: A voice packet forwarding apparatus and method is provided in a digital communication system including a switched vocoder module to directly pass a voice packet received from a packet terminal to a digital communication network or a PCM signal decoded from the voice packet to the digital communication network. The switched vocoder module is also provided to directly pass a voice packet received from the digital communication network to the packet terminal or transmit a voice packet coded from a PCM signal received from the digital communication network. In the presence of additional data to be transmitted to the packet terminal, a data inserter is provided to insert the additional data in the voice packet received from the switched vocoder module and transmit the voice packet with the additional data to the packet terminal. A controller is provided to control the switched vocoder module and the data inserter.

Abstract: An audio signal quality enhancement apparatus and method. The apparatus includes a pitch calculating unit to extract a pitch period of an audio signal, a frequency domain transforming unit to transform the audio signal to a frequency domain, a frequency band dividing unit to classify the transformed audio signal into audio signals for each of the plurality of frequency bands based on the extracted pitch period, and a pitch enhancement unit to determine a gain based on a volume of the transformed audio signal, and to generate an output signal by multiplying each of the classified audio signals with respect to each of the plurality of frequency bands by the gain, thereby enhancing quality of the audio signal.

Abstract: An apparatus and method for deciding an adaptive noise level for bandwidth extension are provided. The apparatus includes a noise level decider for deciding a high-band noise level for bandwidth extension according to tonality of an input signal, a pitch frequency analyzer for detecting a pitch frequency of the input signal and analyzing correlation between the detected pitch frequency and a frequency channel, and a noise level controller for adaptively controlling the decided high-band noise level based on the analyzed correlation of the pitch frequency and the frequency channel.

Abstract: A Unified Speech and Audio Codec (USAC) for adjusting an overlap area of a window based on a transition is provided. To increase an encoding efficiency, encoding may be performed by overlapping relatively long windows. Additionally, when a transition is generated between frames, an overlap area of a window may be reduced based on the transition, thereby preventing a noise from occurring due to the transition.

Abstract: The present invention provides an instrument and method for measuring total luminous flux of luminous elements, which forms an approximately uniform spatial intensity distribution by simultaneously lighting a plurality of luminous elements for measurement in an integrating sphere when comparing a total luminous flux standard lamp with the luminous elements to measure the total luminous flux of the luminous elements, thus not requiring spatial mismatch error correction.

Abstract: An encoding apparatus and a decoding apparatus in a transform between a Modified Discrete Cosine Transform (MDCT)-based coder and a hetero coder are provided. The encoding apparatus may encode additional information to restore an input signal encoded according to the MDCT-based coding scheme, when switching occurs between the MDCT-based coder and the hetero coder. Accordingly, an unnecessary bitstream may be prevented from being generated, and minimum additional information may be encoded.

Abstract: An apparatus and method for deciding an adaptive noise level for bandwidth extension are provided. The apparatus includes a noise level decider for deciding a high-band noise level for bandwidth extension according to tonality of an input signal, a pitch frequency analyzer for detecting a pitch frequency of the input signal and analyzing correlation between the detected pitch frequency and a frequency channel, and a noise level controller for adaptively controlling the decided high-band noise level based on the analyzed correlation of the pitch frequency and the frequency channel.

Abstract: The present invention provides an instrument and method for measuring total luminous flux of luminous elements, which forms an approximately uniform spatial intensity distribution by simultaneously lighting a plurality of luminous elements for measurement in an integrating sphere when comparing a total luminous flux standard lamp with the luminous elements to measure the total luminous flux of the luminous elements, thus not requiring spatial mismatch error correction.

Abstract: Provided are an apparatus for multi-stage transforming a plurality of unit blocks in multi-dimension that can improve compression efficiency of video data by collecting Discrete Cosine Transforming (DCT) coefficients of neighboring blocks and performing an additional transformation based on the DCT coefficients of an original picture and a differential picture. The method includes the steps of: performing a Discrete Cosine Transform (DCT) on inputted picture data and selecting R blocks of a predetermined size from DCT picture data, where R is a natural number equal to or greater than 2; arranging DCT coefficients of each of the selected R blocks according to each frequency in one-dimension; and performing one-dimensional transformation again on the DCT coefficients arranged in one-dimension.

Abstract: A speech compression apparatus including: a first band-transform unit transforming a wideband speech signal to a narrowband low-band speech signal; a narrowband speech compressor compressing the narrowband low-band speech signal and outputting a result of the compressing as a low-band speech packet; a decompression unit decompressing the low-band speech packet and obtaining a decompressed wideband low-band speech signal; an error detection unit detecting an error signal that corresponds to a difference between the wideband speech signal and the decompressed wideband low-band speech signal; and a high-band speech compression unit compressing the error signal and a high-band speech signal of the wideband speech signal and outputting the result of the compressing as a high-band speech packet.

Abstract: An audio signal quality enhancement apparatus and method. The apparatus includes a pitch calculating unit to extract a pitch period of an audio signal, a frequency domain transforming unit to transform the audio signal to a frequency domain, a frequency band dividing unit to classify the transformed audio signal into audio signals for each of the plurality of frequency bands based on the extracted pitch period, and a pitch enhancement unit to determine a gain based on a volume of the transformed audio signal, and to generate an output signal by multiplying each of the classified audio signals with respect to each of the plurality of frequency bands by the gain, thereby enhancing quality of the audio signal.

Abstract: A speech compression apparatus including: a first band-transform unit transforming a wideband speech signal to a narrowband low-band speech signal; a narrowband speech compressor compressing the narrowband low-band speech signal and outputting a result of the compressing as a low-band speech packet; a decompression unit decompressing the low-band speech packet and obtaining a decompressed wideband low-band speech signal; an error detection unit detecting an error signal that corresponds to a difference between the wideband speech signal and the decompressed wideband low-band speech signal; and a high-band speech compression unit compressing the error signal and a high-band speech signal of the wideband speech signal and outputting the result of the compressing as a high-band speech packet.

Abstract: A communication system which has a plurality of mobile terminals and a base station, each of the mobile terminals and/or base station comprising a medium access control sub-layer, upper layers of the medium access control sub-layer, and a lower layer of the medium access control sub-layer, wherein the medium access control sub-layer is configured to perform self-basic functions in response to basic function execution requests or functions associated with the upper layers or lower layer in response to requests therefrom. According to the present invention, the communication system can provide a compatible multimedia communication service even if an originating terminal and a terminating terminal employ different communication manners, they are available from different manufacturers or they are operated by different communication service operators.