Abstract: A system and method for retransmitting an Internet protocol packet for terrestrial digital multimedia broadcasting (DMB) service are provided, in which a PES packetizer and an MPEG-2 TS multiplexer are removed; video, audio, and data signals are individually carried by RTP packets; and a receiver extracts object clock reference (OCR) included in a PEG-4 SL, and synchronizes a system clock and controls buffers by means of the OCR.

Abstract: The present invention relates to a multi fixed-point cell for calibrating a thermometer and a thermometer calibration apparatus using the same, wherein measuring errors can be checked by using a property of constant temperature of a metal on the basis of a phase transition and wide range of temperature region can be measured by one time calibration, thereby capable of increasing efficiencies of time and cost which are taken for calibration. In a multi fixed-point cell for calibrating a thermometer according to the present invention, a thermometer inserting hole in which a thermometer is inserted is formed at one side and at least two reference material inserting holes in which reference materials having different phase transition temperatures are inserted respectively are formed on a same plane as that of the thermometer inserting hole so as to be spaced apart each other.

Abstract: Disclosed is a wavelength-division-multiplexed passive optical network using a wavelength-locked optical transmitter.

Abstract: Disclosed is a remote antenna unit and a wavelength division multiplexing network. The remote antenna unit includes: an optical circulator having a plurality of ports; an electric field absorption modulator having a first input/output end and a second reflective end, the electric field absorption modulator configured to demodulate an optical signal into a first data signal, and modulate the demodulated optical signal according to a second electric data signal; and a filter disposed between the optical circulator and the electric field absorption modulator, for the filter configured to transmit an optical signal having a particular wavelength from among optical signals input from a port of the optical circulator toward the electric field absorption modulator and reflecting the remaining optical signals into the port of the optical circulator, and inputting the optical signal from the electric field absorption modulator into the port of the optical circulator.

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 radio-over-fiber (ROF) system for supporting various services, the system comprising: a central access platform (CAP) for providing time division duplexing (TDD), frequency division duplexing (FDD), and broadcasting services, converting a TDD downward signal and FDD/broadcasting downward signals into optical signals, respectively, transmitting the converted optical signals to a remote access unit (RAU), converting a TDD upward signal and an FDD upward signal, which have been transmitted as optical signals from the RAU, into electric signals, respectively, and using an optical circulator in order to separate upward and downward signals from each other; and the RAU for converting the TDD downward signal and FDD/broadcasting downward signals transmitted from the CAP into electric signals, respectively, converting the TDD upward signal and FDD upward signal to be transmitted to the CAP into optical signals, respectively, and using an optical circulator in order to separate upward and downward signa

Abstract: A remote access unit (RAU) apparatus, coupled to a central station (CS) of an RoF network through at least one optical fiber, and which RAU apparatus includes at least one antenna, includes: first and second antenna ports coupled to the at least one antenna; first and second optical fiber ports coupled to the at least one optical fiber; a first coupler for decoupling a first downstream signal of a first duplexing method and a second downstream signal of a second duplexing method, which are input through the first optical fiber port; a circulator for outputting the first downstream signal input from the first coupler to the first antenna port and outputting a first upstream signal of the first duplexing method input from the first antenna port to the second optical fiber port; and a second coupler for outputting the second downstream signal input from the first coupler to the second antenna port and outputting a second upstream signal of the second duplexing method input from the second antenna port to the sec

Abstract: A radio over fiber (ROF) link apparatus capable of a stable TDD wireless service for a time division duplexing (TDD) baseband signal includes a central access platform (CAP) for receiving various kinds of data including the TDD baseband signal from upper layers, multiplexing the data, electro-optically converting the multiplexed data, and transmitting the converted data as downstream data through an optical fiber, and opto-electrically converting upstream data received through the optical fiber, demultiplexing the converted upstream data, and transmitting the demultiplexed upstream data to the respective upper layers, and a remote access unit (RAU) for receiving the downstream data through the optical fiber, opto-electrically converting the received downstream data to the multiplexed data, demultiplexing the multiplexed data, performing a wireless access process of the demultiplexed data, and transmitting the wireless access processed data to a wireless local area network (WLAN) service terminal through an an

Abstract: Disclosed is an ROF link apparatus for selecting an IF band in order to process various service signals through an MMF, which including transmitters for receiving the service signals, performing IF modulation for the service signals, and transferring the modulated IF signals, a first controller for scanning frequency characteristics of the MMF, searching for flat frequency bands, and transferring information regarding the flat frequency band, thereby controlling IF modulation to be performed, a link unit for combining the IF signals with output signals of the first controller, converting the combined signals into optical signals, transmitting the optical signals, converting the optical signals into electrical signals, and splitting the electrical signals, a second controller for receiving the output signals of the first controller, detecting information regarding the flat frequency band, and transferring the information to receivers, thereby controlling modulation to be performed, and the receivers for receiv

Abstract: Disclosed is a remote access unit for transmitting and receiving upstream and downstream data in which channels having different transmission scheme are multiplexed, and an optical network for bi-directional wireless communication using same. The remote access unit includes an antenna for receiving the downstream data and wirelessly transmitting same and for receiving the upstream data and providing same to the remote access unit, a switch for outputting downstream time division channels of the downstream data to the antenna and for receiving upstream time division channels of the upstream data from the antenna, and a controller for controlling the switch in order to prevent the upstream and downstream time division channels from overlapping.

Abstract: Disclosed is a wavelength-division-multiplexed passive optical network using a wavelength-locked optical transmitter.

Abstract: Disclosed is a remote antenna unit and a wavelength division multiplexing network. The remote antenna unit includes: an optical circulator having a plurality of ports; an electric field absorption modulator having a first input/output end and a second reflective end, the electric field absorption modulator configured to demodulate an optical signal into a first data signal, and modulate the demodulated optical signal according to a second electric data signal; and a filter disposed between the optical circulator and the electric field absorption modulator, for the filter configured to transmit an optical signal having a particular wavelength from among optical signals input from a port of the optical circulator toward the electric field absorption modulator and reflecting the remaining optical signals into the port of the optical circulator, and inputting the optical signal from the electric field absorption modulator into the port of the optical circulator.

Abstract: A Base Transceiver Station (BTS) for interworking a Wireless Local Area Network (W-LAN) and a mobile communication network through a Radio-over-Fiber (RoF) link is provided. The BTS having mobile and fixed wireless service distribution functions includes a Wireless Local Area Network Access Point (W-LAN AP), a wireless service function block, a Radio Frequency (RF) converter, and an optical transmitter. The wireless service function block performs transmission/reception to/from a predetermined mobile terminal via a connection for the voice call communication and data communication with an external Base Station Controller (BSC). The RF converter performs a data communication connection with the external BSC, up-converts data from the BSC into W-LAN frequency band data, and down-converts data to the BSC into baseband data. The optical transmitter transmits the up-converted data of the packet data RF converter to the W-LAN AP through a RoF link.

Abstract: Integrated wired and wireless wavelength division multiplexing passive optical network (WDM PON) apparatus using a light source mode-locked to fed incoherent light includes: a fed light generator for providing fed light for up/downstream signals via a broadband light source emitting an incoherent optical signal; a central office (CO) for receiving, mode-locking, and downstream-optical-transmitting the incoherent optical signal generated by the fed light generator and receiving and optical-detecting an upstream optical signal transmitted from a subscriber unit; and the subscriber unit for receiving, mode-locking, and upstream-optical-transmitting the incoherent optical signal generated by the fed light generator and receiving and optical-detecting a downstream optical signal transmitted from the CO, wherein a wired optical transmitter for transmitting a baseband wired signal and a wireless optical transmitter for transmitting a high frequency radio frequency (RF) signal are comprised for up/downstream optical

Abstract: A fixed-point cell for connection with a thermometer protecting tube and apparatus for estimating the lifetime of thermometerin the thermometer protecting tube including: a reference temperature material layer made of high-purity metallic materials to indicate a reference temperature based on a phase change of material, which coexists in a two-phase or three-phase state; a container part of a multiple structure having the reference temperature material layer embedded and sealed therein for achieving thermal correlation between the reference temperature material layer and the thermometer protecting tube having a thermometer contained therein, the thermometer protecting tube being inserted into the central hole of the fixed-point cell while being in contact with the inner circumference of the container part; and fixing devices disposed on the top portion of the container part for fixing the thermometer protecting tube to the container part in a fastening manner.

Abstract: An optical transmitter for generating return-to-zero alternative-mark-inversion (RZ-AMI) optical signals and a method for generating the optical signals are provided. The optical transmitter includes a light source radiating at its output an intensity-modulated light beam based upon intensity of a first data, a precoder for precoding a second data having the information identical to the first data, and a Mach Zehnder modulator for phase-modulating the intensity-modulated light on basis of the precoded second data to generate a return-to-zero alternative-mark-inversion (RZ-AMI) optical signal.

Abstract: An optical network for bi-directional wireless communication is disclosed. The optical network includes a remote antenna unit for converting a downlink optical signal into a downlink radio signal, transmitting the downlink radio signal wirelessly, and converting an uplink radio signal received wirelessly into an uplink optical signal. An optical line is used as a transmission medium of the downlink optical signal and the uplink optical signal. The optical network also includes a central base station including a circulator linked to the remote antenna unit through the optical line, so that the central base station outputs the downlink optical signal to the remote antenna unit through the circulator and detects the uplink optical signal inputted through the circulator.

Abstract: A wavelength division multiplexed optical access network including a central office for multiplexing first optical signals used for transmitting a high-speed wire data service to a subscriber side and second optical signals used for transmitting a wireless data service to a remote subscriber terminal, a remote node connected to the central office through an optical fiber and for de-multiplexing a multiplexed optical signal received from the central office, a plurality of subscribers connected to the remote node, each subscriber receiving a first optical signal having a corresponding wavelength from among the de-multiplexed first optical signals, and a plurality of radio access units connected to the remote node, each radio access unit converting a second optical signal having a corresponding wavelength from among the de-multiplexed second optical signals into a wireless electric signal and wirelessly transmitting the wireless electric signal.

Abstract: An optical access network of wavelength division method and passive optical network using the same are disclosed. The wavelength division multiplexed optical access network includes a central office for multiplexing first optical signals for wire communication and second optical signals for wireless communication and a remote node connected to the central office through an optical fiber and for demultiplexing a multiplexed optical signal received from the central office. A plurality of subscribers may be connected to the remote node. Each subscriber receives a first optical signal having a corresponding wavelength from among the demultiplexed first optical signals. The network also includes a plurality of radio relay stations connected to the remote node, each radio relay station converting a second optical signal having a corresponding wavelength from among the demultiplexed second optical signals into a radio electric signal and wirelessly transmitting the radio electric signal.

Abstract: A fixed-point cell for connection with a thermometer protecting tube and apparatus for estimating the lifetime of thermometerin the thermometer protecting tube including: a reference temperature material layer made of high-purity metallic materials to indicate a reference temperature based on a phase change of material, which coexists in a two-phase or three-phase state; a container part of a multiple structure having the reference temperature material layer embedded and sealed therein for achieving thermal correlation between the reference temperature material layer and the thermometer protecting tube having a thermometer contained therein, the thermometer protecting tube being inserted into the central hole of the fixed-point cell while being in contact with the inner circumference of the container part; and fixing devices disposed on the top portion of the container part for fixing the thermometer protecting tube to the container part in a fastening manner.