摘要:
An apparatus for measuring Optical Beat Interference (OBI) noise is applied to a central office in a Subcarrier Multiple Access (SCMA) optical network. The central office includes an optical receiver for converting an optical signal received through an optical fiber into an electrical signal. The OBI noise measurement apparatus includes a power divider, first and second filters, and a power measurement unit. The power divider divides the power of a signal output from the optical receiver into two signals. The first filter passes one of the two signals divided by the power divider in a low band of frequencies below a band of subcarrier signals. The second filter passes the other of the two signals divided by the power divider in a high band of frequencies above the band of subcarrier signals. The power measurement unit measures the power of each signal passed through the first and second filters.
摘要:
Provided are an apparatus and method for processing analog monitoring signals by using a serial bus. The apparatus includes a multiplexer receiving at least one analog signal and outputting only one of the at least one analog signal in response to a predetermined control signal; an analog-to-digital converter converting the output analog signal into a digital signal; a first controller generating the control signal, outputting the control signal to the multiplexer, and controlling the operation of the analog-to-digital converter; and a bus controller outputting the digital signal via an external serial bus. Accordingly, analog monitoring signals are received, converted into digital data, and output via serial bus even when a large number of analog monitoring signals are present, only if the address input to the apparatus is identical to unique address of the apparatus.
摘要:
An optical transceiver for transmitting light source control information, which is applied to a Subcarrier Multiplexing optical network, is disclosed. The optical transceiver includes a controller, an SCM frame generation/restoring unit, a modulator/demodulator, and an EO/OE converter. The controller controls transmission of light source control information or collects received light source control information. The SCM frame generation/restoring unit generates an SCM frame containing light source control information received from the controller. The modulator/demodulator modulates an SCM frame generated by the SCM frame generation/restoring unit into a signal suitable for transmission. The EO/OE converter converts a transmission signal modulated by the modulator/demodulator into an optical signal and transmits the optical signal through an optical fiber. An optical network having a telephone office OLT and subscriber ONTs, each having the optical transceiver, is also disclosed.
摘要:
Provided are an optical transmission apparatus and an optical access network for a wavelength-division multiplexing optical network with sub-carrier multiplex and sub-carrier multiple access schemes. The optical transmission apparatus includes: a multiplexer and/or demultiplexer demultiplexing M forward A band optical signals having wavelengths each comprising a plurality of sub-carriers and multiplexing M backward B band optical signals having wavelengths each comprising a plurality of sub-carriers; a plurality of optical power splitters splitting each of the M forward A band optical signals into N optical signals; a plurality of optical receivers receiving backward optical signals belonging to a C band; and M optical transmitters converting the backward optical signals in the C band into the M backward B band optical signals.
摘要:
An optical receiver for use in an Optical Network (ON) such as a WPON based on an SCMA scheme. The optical receiver apparatus for use in a Central Office contained in an ON includes: an optical power divider for dividing an input optical signal into first and second optical signals; a frequency generator for generating a oscillation frequency; a phase shifter for shifting a phase of the oscillation frequency; a first optical modulator for modulating the first optical signal with the oscillation frequency; a second optical modulator for modulating the second optical signal with the oscillation frequency phase-shifted; a first photodiode for converting the optical signal modulated by the first optical modulator into a first RF signal; a second photodiode for converting the optical signal modulated by the second optical modulator into a second RF signal; and a differential amplifier for differentially amplifying the first RF signal and the second RF signal.
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.