Techniques are provided for bi-directional communication between a power supply and one or more light engines (and/or other lighting system components) via the existing power lines so that no additional communication wires are needed. In particular, the power supply can transmit information by modulating its output (voltage or current) and the light engine (or other lighting componentry, such as a sensor) can communicate back by modulating how much power it draws from the power supply. Any suitable type of modulation scheme can be used, and a master-slave arrangement can be used to control the bi-directional communication if so desired, so as to avoid multiple devices communicating over the power line communication channel at the same time. Other embodiments allow a multiple simultaneous communications over the power line communication channel.

Embodiments of the invention provide multiple cyclic prefix lengths for either both the data-payload and frame control header or only the data payload. Frame control header (FCH) and data symbols have an associated cyclic prefix. A table is transmitted in the FCH symbols, which includes a cyclic prefix field to identify the cyclic prefix length used in the data payload. A receiver may know the cyclic prefix length used in the FCH symbols in one embodiment. In other embodiments, the receiver does not know the FCH cyclic prefix length and, therefore, attempts to decode the FCH symbols using different possible cyclic prefix lengths until the FCH symbols are successfully decoded.

A distributed power system including multiple DC power sources and multiple power modules. The power modules include inputs coupled respectively to the DC power sources and outputs coupled in series to form a serial string. An inverter is coupled to the serial string. The inverter converts power input from the serial string to output power. A signaling mechanism between the inverter and the power module is adapted for controlling operation of the power modules. Also, for a protection method in the distributed power system, when the inverter stops production of the output power, each of the power modules is shut down and thereby the power input to the inverter is ceased.

A bus station, a two-wire bus system, and methods for transmitting data in a two-wire bus system. The method includes: supplying a variable battery voltage to a first bus station and a second bus station, and transmitting data from the first bus station to the second bus station using a modulation signal that is superposed on the variable battery voltage, wherein the modulation signal is adjusted to follow a level of the variable battery voltage in a predefined manner.

Aspects of the subject disclosure may include, a system that can be configured for generating an electromagnetic wave and coupling the electromagnetic wave to a transmission medium with a reduced loss of radiation of the electromagnetic wave into free space. The system can also be configured to receive an electromagnetic waves form the transmission medium with a reduced loss of radiation of the electromagnetic wave into free space. Other embodiments are disclosed.

A method for testing a detection sensor positioned facing a target fixed to a drive shaft that is intended to be installed in a motor vehicle. The method includes generating a pulsed voltage test signal, amplifying the high states of the generated test signal, filtering the amplified test signal so as to obtain a voltage test signal having high states the voltage of which is higher than a predetermined high-state detection threshold and low states the voltage of which is lower than a predetermined low-state detection threshold, and detecting the high states and the low states of the filtered test signal in order to test the sensor.

Methods, and apparatus for determining inertia within a synchronous area of an electric power grid are described. A frequency characteristic relating to a frequency of electricity flowing in the electric power grid is measured, a magnitude relating to a power flow modulation is determined based on data relating to power characteristics of one or more power units arranged to consume electric power from and/or provide real and/or reactive electric power to the electric power grid, and a frequency response characteristic associated with at least one area of the electric power grid is determined on the basis of the measured frequency characteristic and the determined magnitude characteristic. This enables frequency response characteristics within a synchronous area of the electric power grid to be easily determined.

Methods, apparatus and computer programs for transmitting and/or receiving information are described. Information encoded in a carrier signal comprising a modulation pattern superimposed on a grid frequency at which electricity flows in a synchronous area of an electric power grid, is decoded by measuring, at a receiving device, a characteristic relating to a frequency of electricity flowing in the electric power grid, accessing data indicative of one or more predetermined code patterns and performing a correlation process to determine a correlation between the modulation pattern and one of the one or more predetermined code patterns. The information is decoded on the basis of the determined correlation. This enables information to be easily transmitted within a synchronous area of the electric power grid.

A power line communication apparatus includes a drive block including an actuator control circuit and a drive circuit and a communication block. The actuator control circuit generates a control pulse for controlling an actuator, and controls a transition timing of the control pulse during an operation period set within a communication cycle by a communication clock. The drive circuit controls a driving current of the actuator supplied from a DC power source through a power line based on the control pulse in which the transition timing is controlled. The communication block generates the communication clock, and modulates a current flowing through the power line in response to data to be transmitted during a signal transmission period different from the operation period, set within the communication cycle.

Methods and apparatus are disclosed for communicating between an aircraft and a terminal when the aircraft is on the ground. The connection between the aircraft and the terminal is made over a ground power line while the aircraft is being supplied with power. The ground power line comprises one or more wires, which are typically unshielded and cause radio interference. At the transmitting end, multiple copies of the same signal offset in phase relative to one another over the ground power line. Each data stream is coupled to a respective wire in the ground power line. At the receiving end, the multiple copies of the signal are extracted from the respective wires of the ground power line and combined to generate a combined signal with improved signal-to-noise ratio. Radio interference is suppressed by transmitting the data streams in a phase offset manner so that the unwanted emissions cancel.