Abstract: Disclosed are a system and method for providing digital multimedia broadcasting confinement service. The system includes: a relay center side system, which is adopted to the relay center, according to the relay center side packet identification description (PID) key, for modifying the PID of transport stream and generating the distorted program specific information (PSI); and a terminal side system, which is adopted to the DMB terminal, according to the terminal side PID key, for recovering the distorted PSI of the transport stream received from the relay center and decoding it. The method includes the steps of: identifying whether the actual PID of the TS is consistent when the TS is demultiplexed by audio/video PID acquired through the program map table (PMT) analysis of the TS; generating a preset alarm signal; modifying the PID of the audio/video data in the PMT according to the terminal side PID; and demultiplexing the TS according to the modified PID value.

Abstract: Provided is a system for communicating between a base station transceiver subsystem and radio access units in a wireless communication system. The system includes a data path switch for switching a signal received from a base station controller, to a predetermined picocell, a micro cell HD controller and a picocell HD controller for detecting header information of the received signal, and controlling the data path switch, a picocell power meter for receiving a signal strength from a mobile terminal, and performing a power control, a modem for processing and transmitting the signal to an optical transceiver, and processing and transmitting a signal received from the optical transceiver to the data path switch and an optical transceiving unit for receiving and converting an electric signal into an optical signal, and receiving and converting an optical signal into an electric signal.

Abstract: An optical wavelength tracking apparatus and method in a wavelength division multiplexed (WDM) passive optical network (PON) in which a central office (CO) having a multi-frequency light source is connected to a plurality of optical network units (ONUs) having loop-back light sources through a WDM MUX/DEMUX in a remote node (RN). The power levels of downstream and upstream WDM optical signals are measured. The WDM wavelengths of the multi-frequency light source and the WDM MUX/DEMUX are controlled to be nearly identical in order to minimize the difference between the power levels of the downstream and upstream WDM optical signals.

Abstract: A passive optical network includes a central office and a subscriber-side apparatus connected with the central office through an optical fiber link. The subscriber-side apparatus performs communication with the central office based on wavelength-division-multiplexed optical signals. The central office has a routing section, provided with first to fourth multiplexing ports, for demultiplexing multi-wavelength light inputted from the fourth multiplexing port into a plurality of channels. Each of the demultiplexed channels is amplified and multiplexed for output through the first multiplexing port. Optical signals inputted through the third multiplexing port are demultiplexed and outputted upstream. The routing section also multiplexes channels for downstream optical signals, outputting the multiplexed channels through the second port. A splitting section, provided with first to third splitting ports and arranged on a loop optical waveguide connects the first and fourth multiplexing port with each other.

Abstract: A multi-wavelength light source unit for optical communication system is disclosed. The light source includes a demultiplexer for demultiplexing a multiplexed light signal into a plurality of lights having different wavelengths and a multiplexer that receives the demultiplexed lights and multiplexes the demultiplexed lights into the multiplexed light signal. Input ports of the multiplexer are respectively port-to-port connectable to each one of a plurality of output ports of the demultiplexer. The light source unit includes a plurality of semiconductor optical amplifiers amplifying the demultiplexed lights output form the demultiplexer, and a plurality of beam splitters for splitting the amplified demultiplexed lights into two parts, so as to provide the respective input ports of the multiplexer with a split part of the lights, while to transmit the other part of the lights out of the beam splitters.

Abstract: Disclosed is color conversion method using a color look-up table. The method includes the steps of: generating a color look-up table using information on the difference of each channel before and after a conversion of each color; and converting the colors using the generated color look-up table. The step of generating the color look-up table includes identifying the maximum difference value among several difference values and generating a first compressed table to initially compress the difference values using the maximum difference value.

Abstract: A retransmission apparatus is provided that uses a packet method for a DMB service and includes: a DMB receiver for receiving DMB data from a medium; a DMB transmission mode release unit that outputs an MPEG-2 TS by releasing a DMB transmission mode in the DMB data received from the DMB receiver; a channel information extractor that extracts channel information contained in a Fast Information Channel (FIC) of the DMB data in the DMB transmission mode release process of the DMB transmission mode release unit; a data information extractor that receives the MPEG-2 TS from the DMB transmission mode release unit and extracts data information indicating a location of an elementary stream from the received MPEG-2 TS; a channel information database (DB) that stores the channel information extracted by the channel information extractor and the data information extracted by the data information extractor as channel data; a first IP streamer that IP-streams the MPEG-2 TS output from the data information extractor; and a

Abstract: An optical network is provided. The optical network includes a station to convert a downstream radio frequency (RF) signal to a downstream optical signal and convert an upstream optical signal to an upstream RF signal; and a remote access unit (RAU) to convert the downstream optical signal to a downstream RF signal and to convert the upstream RF signal to the upstream optical signal, wherein the RAU determines a non-transmission band portion on which data is not carried from the downstream RF signal and inputs upstream data in the non-transmission band.

Abstract: Disclosed is a color conversion method, the method including the steps of (a) converting a color using an approximation technique, and (b) correcting an error of the color using a preset error correction table containing information regarding a difference between a color channel based on an original conversion formula and a color channel based on the approximation technique.

Abstract: A retransmission apparatus using an IP multicasting method for a DMB service including a plurality (n) of radio frequency (RF) receivers, each for receiving a DMB RF signal of a corresponding channel, a plurality (n) of DMB decoders, each for outputting a transport stream (TS) by decoding the DMB RF signal received from a corresponding RF receiver, a plurality (n) of slicers, each for processing the TS input from a corresponding DMB decoder; a plurality (n) of network interfacers, each for IP packetizing the TS sliced by a corresponding slicer; a network switch for receiving the IP packets from the plurality (n) of network interfacers, transferring the received IP packets to a multicasting processing unit, and receiving multicasting data from the multicasting processing unit, and the multicasting processing unit for receiving the IP packets from the network switch, creating a single piece of multicasting data by assigning multicasting addresses to the received IP packets, and outputting the created multicasti

Abstract: Disclosed are methods and devices for adjusting an image color in an image projector. In one aspect, the method for adjusting an image color in an image projector, includes the steps of obtaining information on an external image projection environment to determine color conversion information for adjusting the color of a projection image and converting the color of an image to be projected using the determined color conversion information to project the image. The device for adjusting a projection image color in a mobile communication terminal provided with an image projector, includes an image projector for performing an image projection function under the control of a controller, a camera for performing a camera function under the control of the controller; and the controller for obtaining color information of an external screen on which an image is projected through the camera, and adjusting the color of an image to be projected onto the image projector using the color information.

Abstract: A subscriber interface device and method for transmitting a communication signal and a broadcasting signal to each subscriber in a communication-broadcasting convergence FTTH system. A subscriber interface, positioned in the ONU, modulates a first predetermined number of broadcasting signals selected by a subscriber among broadcasting signals received from an OLT, combines a baseband communication signal received from the OLT with the modulated broadcasting signals, and optically transmits the combined communication-broadcasting signal. A subscriber interface receiver positioned in an ONT, splits the combined communication-broadcasting signal, filters the split signals to respective frequency bands, modulates the filtered broadcasting signals, transmits the modulated broadcasting signals to a monitor of the subscriber, and transmits the filtered communication signal as a baseband signal to a communication terminal of the subscriber instead of a passband signal.

Abstract: A method for controlling optical transmitters in a Wavelength Division Multiplexed (WDM)-Passive Optical Network (PON) system includes the steps of: determining the existence of an upward optical signal to control an optical transmitter provided for each corresponding Optical Node Terminal (ONT) to be turned on/off in an Optical Line Termination (OLT); and monitoring the state of a transmission buffer within an Ethernet switch to control a corresponding optical transmitter to be turned on/off in accordance with the state of the transmission buffer in each of the ONTs.

Abstract: A bidirectional optical add-drop multiplexer adds and drops optical signals having specific wavelengths among the WDM optical signals transmitted bidirectionally through one of the optical transmission lines connected between neighbor nodes in a bidirectional WDM ring network.

Abstract: A method for updating contents of a Digital Media Server (DMS) in a digital living network alliance system (DLNA) is dislcosed. An update process is performed through a periodic update event in a Digital Media Player (DMP) that receives all content information of the DMS. Upon determining that information loss has occurred in the update process, the DMP sends to the DMS a request for information about a list of items possessed by the DMS. The DMP receives the requested information about the list of items and compares the received information about the list of items with information about pre-stored items to obtain a comparison result. When a difference occurs as the comparison result, all information about contents of the DMS is obtained through a browse action. When the difference does not occur as the comparison result, the update process is continuously performed.

Abstract: Disclosed is a wavelength division multiplexing optical switching system, which is connected with a plurality of nodes of an optical network and supports communication between the nodes. The optical switching system includes a wavelength division demultiplexing unit which demultiplexes optical signals received from each of the plurality of nodes and outputs them as channels with different wavelengths. A routing unit which classifies the channels in accordance with destinations thereof. A fixed wavelength converting unit which converts the classified channels into channels of a single wavelength, the single wavelength being allocated in accordance with corresponding starting places. A wavelength division multiplexing unit which collects the wavelength-converted channels in accordance with destinations and then outputs them as multiplexed optical signals.

Abstract: Disclosed is a bidirectional optical add/drop multiplexer that includes a first filter for reflecting a first optical signal pre-selected among input forward optical signals and transmitting the remaining forward optical signals, a second filter for reflecting a second optical signal pre-selected among input reverse optical signals and transmitting the remaining reverse optical signals, a first optical splitter for combining the first optical signal and the forward optical signals by reflection from the first filter, wherein the reflected second optical signal having passed through the first filter is outputted to a connected second drop terminal and the first optical signal input from a connected first add terminal is outputted to the first filter, and a second optical splitter for adding the second optical signal and the reverse optical signals by reflection from the second filter, wherein the reflected first optical signal having passed through the second filter is outputted to a connected first drop termi

Abstract: A duobinary optical transmission apparatus is provided to generate duobinary optical signals, without using an electric low-pass-filter (LPF), by restricting a bandwidth of a Mach-Zehnder-interferometer-type optical intensity modulator (MZ MOD). Alternatively, a LPF having a single pole with a single capacitor is implemented instead of an expensive LPF, thereby providing a simple transmitter with a lower production cost in comparison with a transmitter using a conventional electric LPF.

Abstract: A burst-mode optical receiver of a differential-output structure is disclosed.

Abstract: An optical transmission system for optimizing the bias of a laser diode during an SCM analog optical transmission includes an optical transmitter for converting a baseband electric signal into an optical signal using a laser diode according to the set bias and outputting the optical signal through an optical line, an optical receiver for converting the optical signal transmitted from the optical transmitter into the baseband electric signal, a recovery unit for detecting an error generated according to the bias of the laser diode on the basis of the electric signal converted by the optical receiver, and a bias adjuster for optimally adjusting the bias of the laser diode on the basis of a value of the error detected by the reproducer.