摘要:
An optical transmission system for removing skew between optical channels is provided. The optical transmission system comprises an optical signal transmitter and an optical signal receiver. The optical transmitter inserts serial numbers into an overhead of a frame, delays the frame by a time corresponding to skew information transmitted from an opposite optical transmission system, and transmits the frame. The optical signal receiver receives the frame from the opposite optical transmission system via fiber optics, removes skew existing in the received frame in units of both a byte and a frame by referring to the serial numbers stored in the overhead of the frame, and transmits the skew information collected when the skew is removed, to the opposite optical transmission system.
摘要:
A channel equalizer includes a channel estimator, a coefficient calculator, a multiplier, and an error remover. The channel estimator estimates a channel impulse response (CIR) of input data in which a known data sequence is periodically inserted. The coefficient calculator calculates equalization coefficients using estimated CIR, and the multiplier multiplies the input data with the equalization coefficients for channel equalization. The error removes estimates a residual carrier phase error of the channel-equalized input data and removes the estimated phase error from the input data.
摘要:
A PLC-based wavelength-tunable WDM-PON system with an optical wavelength alignment function, the WDM-PON system comprises: a PLC platform formed on a silicon substrate; a semiconductor chip comprising an active region generating light and a passive region located in front of the active region for vertically coupling the light generated in the active region; a planar lightwave circuit (PLC) waveguide; one portion of a PLC platform where the semiconductor chip is surface mounted; waveguide Bragg grating (WBG) formed at a predetermined location of the PLC waveguide; a directional coupler transferring an optical power by permitting the passive region to approach the PLC waveguide; a heater terminal, which is formed on the WBG; and a V-groove for attaching an optical fiber to another end of the PLC waveguide. Accordingly, a WDM-PON system having a function of realizing a cost-effective optical wavelength alignment can be provided.
摘要:
A video data communication method and apparatus for a data communication that enable improving video quality, at a recipient device, and transmission efficiency by transmitting video data using both contention free transmission mechanism and priority-based transmission mechanism are provided. A video data transmission method ion includes dividing video data into different types of slices; assigning different transport priorities to slice types in accordance with importance for recovering, at a recipient device, the video data; and transmitting the slices on the basis of the transport priorities.
摘要:
A reflective semiconductor optical amplifier (RSOA) and an operating system based on a downstream optical signal reuse method with feed-forward current injection are provided. The RSOA has two active regions and includes a reflecting plane that reflects an input optical signal; and an optical amplifying semiconductor including a rear portion, which is positioned at a side of the reflecting plane and to which a signal having polarity opposite to that of the input optical signal is injected, and a front portion, which is positioned at a side opposite to the side of the rear portion facing the reflecting plane and which the input optical signal is passed though and a signal used to modulate a reflected input optical signal from the reflecting plane to an output optical signal is injected into.
摘要:
A DTV transmitter includes a pre-processor expanding original enhanced data, a data formatter generating enhanced data packets including the expanded enhanced data and inserting known data place holders into the data packets, a multiplexer multiplexing the enhanced data packets with main data packets including main data, and an RS encoder adding systematic RS parity data to each main data packet and adding non-systematic RS parity data holders to each enhanced data packet. It further includes a data interleaver interleaving the RS-coded data packets, a known data generator generating know data symbols, a converter converting the interleaved data packet into symbols, and a symbol processor processing the converted symbols. The symbol processor removes symbols representing the null data, encodes symbols representing the original enhanced data at a rate of N/M, and replaces symbols representing the know data place holders with known data symbols.
摘要:
Provided is a method of increasing the number of subscribers using a time division duplexing (TDD) technology in a wavelength division multiplexing (WDM)/Ethernet passive optical network (WE-PON) system, and more particularly, a method of increasing the number of subscribers admissible per wavelength using a TDD technology. In an existing WE-PON, due to an amplitude squeezing effect (ASE) in an optical network terminal (ONT) and an optical output power restriction in an optical line terminal (OLT), there is a disadvantage in that 4 or more subscribers cannot be simultaneously accommodated per wavelength. However, the present invention enables accommodation of a maximum of 16 subscribers per wavelength by applying a TDD technology to a medium access control (MAC) protocol. Point-to-multipoint services can be provided without the need of an additional header for classifying upstream and downstream window sizes in a downstream bandwidth used in an existing WDM-PON loopback technique using dynamic band allocation (DBA) applied to a conventional E-PON MAC protocol and scheduling algorithm. In addition, a DBA and threshold adjustment mechanism are provided to compensate for a downstream bandwidth decrease caused by application of the TDD technology.
摘要:
A digital broadcast transmitting/receiving system and a method for processing data are disclosed. The method for processing data may enhance the receiving performance of the receiving system by performing additional coding and multiplexing processes on the traffic information data and transmitting the processed data. Thus, robustness is provided to the traffic information data, thereby enabling the data to respond strongly against the channel environment which is always under constant and vast change.
摘要:
A digital broadcast transmitting/receiving system and a method for processing data are disclosed. The method for processing data may enhance the receiving performance of the receiving system by performing additional coding and multiplexing processes on the traffic information data and transmitting the processed data. Thus, robustness is provided to the traffic information data, thereby enabling the data to respond strongly against the channel environment which is always under constant and vast change.
摘要:
Disclosed is a wavelength tunable light source module for wavelength division multiplexing passive optical network systems, which is capable of being realizing at low costs, increasing utility of wavelength resources, and facilitating mass production. The wavelength tunable light source module comprising: a temperature adjustment unit for raising or lowering ambient temperature according to heat generation or heat absorption caused by an electrical signal, a support block attached to the temperature adjustment unit and having a structure for fixing a laser diode, and a TO-can type distributed feedback laser diode mounted on the temperature adjustment unit by the support block and having an operation wavelength varied according to the ambient temperature adjusted by the temperature adjustment unit.