摘要:
A tunable high-order Bessel low pass filter which is applied to a multi-rate duobinary generation system of an optical communication system. The tunable Bessel low pass filter comprises a variable inductor circuit including a plurality of variable inductors connected in series between an input signal terminal and an output signal terminal and controlled respectively by corresponding inductance control signals, a variable capacitor circuit including a plurality of variable capacitors connected respectively between corresponding connection nodes of the plurality of variable inductors of the variable inductor circuit and a ground terminal and controlled respectively by corresponding capacitance control signals, and a variable capacitor/inductor controller for outputting the corresponding capacitance control signals to the variable capacitors of the variable capacitor circuit and the corresponding inductance control signals to the variable inductors of the variable inductor circuit on the basis of preset values according to a given data rate, respectively. When the data rate of an application system is changed, the tunable Bessel low pass filter controls its filtering characteristics most appropriately to the changed data rate, so as to extend its application range and enhance performance and efficiency of the application system.
摘要:
The present invention relates to an apparatus and method for automatically correcting a bias voltage for a carrier suppressed pulse generating modulator using the phase distribution of the output pulses, which automatically detects an optimal bias voltage for the carrier suppressed pulse generating modulator and stabilizes the bias voltage. In the bias voltage automatic correction method and apparatus of the present invention, an optimal bias voltage for the modulator is set to a bias voltage that is obtained when mean power of an optical signal output from the modulator is highest. The varying direction of the bias voltage is detected on the basis of the phase variations in the output optical signal of the modulator according to the bias voltage variations is detected, and the bias voltage is corrected oppositely to the varying direction of the bias voltage.
摘要:
Disclosed herein is an apparatus for controlling a decision threshold voltage to an optical receiver, which is capable of automatically controlling the decision threshold voltage to the optical receiver appropriately to signal level decision on the basis of a low-frequency band signal component of an output signal from the optical receiver. The apparatus is adapted to control the level of the decision threshold voltage to the optical receiver, which converts an input optical signal into an electrical signal. To this end, the apparatus comprises a voltage detector for branching off part of the output signal from the optical receiver and detecting a corresponding voltage, a differential comparator for comparing the voltage detected by the voltage detector with a reference voltage inputted thereto and outputting the resulting differential voltage, a low pass filter for filtering the differential voltage from the differential comparator at a predetermined low frequency band and supplying the resulting voltage as the threshold voltage to the optical receiver, and a voltage controller for controlling the reference voltage to the differential comparator on the basis of a differential voltage between the threshold voltage from the low pass filter and a predetermined voltage corresponding to a predetermined minimum bit error rate.
摘要:
Provided is an apparatus for stabilizing a wavelength for optical communications which includes a digital control circuit unit and an analog control circuit unit to stabilize a wavelength that may be shifted at the time of driving an optical source for optical communications. The wavelength can be precisely controlled according to a modulation format using the optical source for optical communications, and thus performance can be stabilized.
摘要:
An optical transceiver case is provided. The optical transceiver case has an optical transmission/reception device and a PCB that operates the optical transmission/reception device. The optical transceiver case includes a lower plate and an upper plate. The lower plate supports the optical transmission/reception device and the printed circuit board, and includes handle grooves formed on both external sides of the lower plate to allow the optical transceiver case to be mounted/detached to/from an optical transmission/reception system's board. The upper plate is coupled to the lower plate to mount the optical transmission/reception device and the printed circuit board, and includes a protuberance embossed on an external upper surface of the upper plate in order to discharge heat generated from the optical transmission/reception device and the PCB to the outside. The optical transceiver case is easily mounted detached to/from on optical transmission/reception system's board and maintains a constant internal temperature.
摘要:
A system and a method for providing a secured transmission through an authenticated encryption for each ONU in downlink transmission of an OLT in GPON are provided. The GPON system includes an OLT for generating a GTC downlink frame by receiving data from an external service provider and ONUs for receiving the GTC downlink frame from the OLT and processing the received GTC downlink frame. The OLT performs the authenticated encryption for the generated GTC downlink frame according to the ONU by including an authentication generator and the ONU determines whether the GTC downlink frame is allowed to be processed or not by checking the authentication of the received GTC downlink frame through an authentication checker.
摘要:
A mobile terminal executes a navigation function by receiving Transport Protocol Experts Group (TPEG) traffic information through a Digital Multimedia Broadcasting (DMB) network. This DMB-based mobile terminal receives and decodes TPEG data at a separate second processor different from a conventional first processor. Further, the DMB-based mobile terminal may execute a calculation of an optimum route at the second processor. The terminal and a related method reduce the processing load of the first processor, which causes a decrease in the response time to a user's navigation request and improves a user's convenience.
摘要:
Disclosed are a hinge assembly and a mobile device having the hinge assembly. In the mobile device, a rotation portion 14 slides and rotates on a base portion 10, so as to be inclined to the base portion 10. For this reason, the rotation portion 14 is connected to the base portion by means of the hinge assembly 20 so as to slide and rotate on the base portion 10. The rotation portion 14 slides on the base portion by a predetermined distance, and then rotates to be inclined at a desired angle with respect to the base portion 10. The rotation portion 14 easily rotates with respect to the base portion of the mobile device, so that the status of the mobile device can be easily converted. Further, when the status of the mobile device is converted, the front, rear, left and right of a display screen is not changed. As a result, the mobile device should not have a structure of changing a display direction of the display screen. Further, there is an advantage in that an electric connection between the base portion and the rotation portion by means of a connection link mechanism can be stably achieved.
摘要:
An embodiment of the invention provides an apparatus and method for varying a voltage controlled oscillator (VCO) sensitivity. A VCO has an oscillator portion coupled to a variable current supply. The variable current supply has one or more enabled variable current cells. The enable variable current cell input provides a control to change the VCO sensitivity. In an example, the oscillator portion has a ring oscillator. In an example, the variable current supply has at least two variable current cells that supply the control current. A binary control signal alters a quantity of variable current cells that supply the control current. Each successive variable current cell has an output current substantially equal to twice that of a prior variable current cell.
摘要:
Provided is a method for setting a security channel between an OLT and at least one ONU in an EPON. In detail, a channel is generated by which the OLT makes a reciprocal security capability agreement with the ONU that wants to set a security channel in a discovery interval and then automatically registers the ONU with the security capability agreement. The security channel is set by which the OLT distributes an encryption key for the security with the ONU completed with the security capability agreement. A renewal point of the encryption key is shared by transmitting a message indicative of a time to change the encryption key between the OLT and the ONU both completed with the encryption key distribution.