Optical network systems are disclosed, including a transmitter comprising a digital signal processor that receives data; circuitry that generate a plurality of electrical signals based on the data; a plurality of filters, each of which receiving a corresponding one of the plurality of electrical signals, a plurality of roll-off factors being associated with a respective one of the plurality of filters; a plurality of digital-to-analog converter circuits that receive outputs from the digital signal processor, the outputs being indicative of outputs from the plurality of filters; a laser that supplies light; and a modulator that receives the light and outputs from the digital-to-analog converter circuits, the modulator supplying a plurality of optical subcarriers based on the outputs of the digital-to-analog converter circuits, such that one of the plurality of optical subcarriers carrying information for clock recovery.

n wavelengths set such that delay differences between optical signals due to wavelength dispersion in an optical fiber between accommodation and base stations are at equal intervals are assigned to n antenna elements of the base station which are at predetermined intervals. The accommodation station adjusts the phases of optical signals of the wavelengths or modulated signals that modulate the optical signals such that the amounts of phase shift of their RF signals are at predetermined intervals. The accommodation station transmits beacon signals multiple times while varying a transmission phase shift interval α.sub.1 and the terminal transmits beacon number information of a beacon signal selected based on received power multiple times. The accommodation station varies a reception phase shift interval α.sub.2 for each piece of beacon number information to determine a reception phase shift interval α.sub.2 which maximizes the received power and determines the transmission phase shift interval α.sub.1 based on the beacon number information received from the terminal.

Methods and apparatus for reducing and/or canceling signal interference between receiver and transmitter components of a wireless communications device are described. The methods and apparatus are well-suited for use in a wide range of devices including user equipment devices such as cell phones as well as in network equipment such as base stations. Opto-mechanical devices are used in some embodiments as part of an apparatus which performs interference cancelation on RF (Radio Frequency) signals.

Technologies and techniques for operating an electro-optical transmission device. An optical carrier signal is generated via an optical signal source of a base unit of the transmission device. An arbitrary signal is generated via the optical signal source, and the arbitrary signal is modulated onto the optical carrier signal in the base unit, forming a transmission signal. The transmission signal is transmitted to an antenna unit of the transmission device via an optical transmission medium, and the arbitrary signal and the carrier signal are separated in the antenna unit. Aspects also are directed to a computer program product and to a transmission device configured to perform such functions.

Systems and methods for testing operations for distributed device systems may use a test signal that is generated at a central unit and looped back internally within the central unit to test the central unit. The test signal may then be sent over a communication medium to a remote unit and looped back to the central unit to test the communication path. Further, the remote unit may include a testing circuit to test internally. By sequentially testing devices within the distributed device system, problems may be isolated and potentially repaired without having to return a device to a manufacturer facility. Even when such returns are needed, only the problematic device is returned, potentially saving time in the installation.

A terminal (1050) includes a light receiver (151) that receives a light signal emitted by an apparatus (1000), the light signal including an identifier (SSID) of at least one base station (470); a receiver (153) that performs a reception process on the received light signal to output reception data; a data analyzer (155) that selects one base station based on the identifier of the at least one base station that is included in the reception data; and a radio device (453) that establishes a wireless connection with the selected base station (470) by using the identifier of the base station (470) and wirelessly communicates with the base station (470).

The present disclosure relates to an optical line terminal, OLT, which is enabled to range optical network units, ONUs, in a point-to-multipoint optical network by detecting interference burst sequences transmitted by one or more joining ONUs during transmission of upstream data traffic from transmitting ONUs. The present disclosure further relates to an optical network unit, ONU, which is enabled to transmit, at a selected transmission time, an interference burst sequence including a sequence of pulses allowing the OLT to identify the ONU as a joining ONU.

An optical-electronic integrated RF leakage interference cancellation system and method for continuous wave radars belongs to the technical filed of radars. The optical-electronic integrated RF leakage interference cancellation system cancels the RF leakage interference by integrating of the microwave photonic link and the cable link. The microwave photonic link implements the phase adjustment, time delay adjustment and amplitude adjustment of the microwave signal tapped from the continuous wave source in the transmitter and realizes the cancellation matching conditions of the out of phase, the matching delay time and the same amplitude with the leakage interference signal. It has the advantages of broad frequency band, large bandwidth, and high tuning resolution, which enables the effective suppression of the RF leakage interference and ensures the high transmit-to-receive isolation for continuous wave radars.

There is provided a method and device for forwarding a digital signal arranged into portions that each contain a timestamp and an error detection code. Duplicates of the digital signal are received on a first optical path and a second, separate optical path. Corresponding timestamps are identified in the signals and used to synchronize corresponding portions of the signals. The error detection codes in the synchronized portions are used to allow one and only one of the corresponding portions to be selected for forwarding. The selected portions are then forwarded.

An electro-optic system, the electro-optic system that may include an input port that is configured to receive a bandpass signal that conveys information; wherein the bandpass signal is a radio frequency (RF) signal; an optical carrier source that is configured to generate an optical carrier signal having an optical carrier frequency; at least one electrical bias circuit that is configured to generate at least one electrical bias signal; an electro-optic modulation circuit that is linear at the optical field; a manipulator that is configured to (a) receive the at least one electrical bias signal and the bandpass signal, (b) generate, based on the at least one electrical bias signal and the bandpass signal, at least one modulating signal; wherein the electro-optic modulation circuit is configured to modulate the optical carrier by the at least one modulating signal to provide an output optical signal that comprises at least one optical pilot tone and at least one optical sideband that conveys the information.