Disclosed is a method for communication, according to a TDMA protocol, between a master device and at least one slave device, during which a plurality of frames are transmitted between the master device and the slave device, each frame being partitioned into a plurality of time intervals, at least one time interval having an analogue synchronization signal having an amplitude regulation portion in the form of a sine wave having a constant amplitude over a number of predetermined pulses, and an optimized synchronization portion in the form of a triangular amplitude modulation of the sine wave so as to determine a reference time.

A method includes computing electrical phase of electrical metering devices including obtaining data indicating zero-crossing times at first and second metering devices. A time difference between the zero-crossing times may be determined. In a first example, the time difference may be based at least in part on calculations involving a first value of a first free-run timer on a first metering device, a second value of a second free-run timer on a second metering device, the time of reception of a packet, and a latency defined by a time taken for the packet to propagate through at least one layer of at least one of the first metering device and the second metering device. A phase difference between the first zero-crossing and the second zero-crossing may be determined, based at least in part on the determined time difference.

A method and a device are disclosed including a PLC node having a synchronizer, a modem with a transceiver, and a computing device coupled with a power line for power line data communications. In various embodiments, a coordinator or Data Concentrator Unit (DCU) coordinates the communication of PLC nodes. The PLC nodes are configured to detect a zero crossing of the power line wave form and transmit or receive data within time slots defined with respect to the detected zero crossing. In other embodiments, the time slots may be synchronized using a frame sync signal, an external signal, or polling. In various embodiments, the time slots may be random access or assigned. In some embodiments, the modem and/or node may be placed in a sleep mode when not communicating to reduce power consumption and be awaken when an allocated time slot is approaching.

Systems and methods are disclosed for detection of a selected signal pattern, such as a servo sector preamble, and for frequency offset determination. A circuit may be configured to divide a signal into detection windows of a selected size, and sample the signal a selected number of times within each detection window. The circuit may then determine an error value for each detection window based on values of the samples for each detection window, and determine the preamble is detected when a threshold number of most-recently sampled detection windows have error values below a threshold value. The circuit may then organize the sample values corresponding to the preamble into groups, and calculate phase estimates representing a phase at which the groups were sampled. The circuit may determine a frequency offset based on the phase estimates, and modulate the sampling frequency according to the frequency offset.

A coded light receiver comprising a sensor for receiving coded light, a filter, and a timing and data recovery module. The coded light comprises a signal whereby data and timing are modulated into the light according to a self-clocking coding scheme. The filter is arranged to match a template waveform of the coding scheme against the received signal, thereby generating a pattern of filtered waveforms each corresponding to a respective portion of the data, and the timing and data recovery module recovers the timing from the signal based on characteristic points of the filtered waveforms. The timing and data recovery module is configured to do this by separating the filtered waveforms into different sub-patterns in dependence on the data, and to recover the timing by processing each of the sub-patterns individually based on the characteristic points of each sub-pattern.

A method includes computing electrical phase of electrical metering devices including obtaining data indicating zero-crossing times at first and second metering devices. A time difference between the zero-crossing times may be determined. In a first example, the time difference may be based at least in part on calculations involving a first value of a first free-run timer on a first metering device, a second value of a second free-run timer on a second metering device, the time of reception of a packet, and a latency defined by a time taken for the packet to propagate through at least one layer of at least one of the first metering device and the second metering device. A phase difference between the first zero-crossing and the second zero-crossing may be determined, based at least in part on the determined time difference.

In a method for operating a device comprising an internal clock generator and an internal clock and being connected to a network, the internal clock is incremented by the internal clock generator. Moreover, the internal clock is synchronized with a network frequency of the network.

Techniques for computing electrical phase of electrical metering devices are described. In an example, data indicating zero-crossing times at first and second metering devices is obtained. A time-difference between the zero-crossing times may be determined. In a first example, the time-difference may be based at least in part on calculations involving a first value of a first free-run timer on a first metering device, a second value of a second free-run timer on a second metering device, and a time of a transmission between the metering devices. In a second example, the time-difference may be based at least in part on calculations involving a start or end time of a time-slot of a spread spectrum radio frequency transmission scheme. A phase difference between the first zero-crossing and the second zero-crossing may be determined, based at least in part on the determined time-difference.

The present invention relates to a system for performing phase detection and synchronization in an AMI communication network using a relay communication, and a method thereof. According to an embodiment of the present invention, a system for performing phase detection and synchronization in an AMI communication network using a relay communication includes an AMI server for collecting a ‘reference zero-crossing detection (ZCD) time difference by phase’ of input/output terminals of a main transformer installed in a substation; and a data concentration unit (DCU) comparing the ‘reference ZCD time difference by phase’ transmitted from the AMI server with a ‘ZCD time difference by phase’ collected by itself, and matching the same to have a time difference close to an error range.

The present invention relates to a system for performing phase detection and synchronization in an AMI communication network using a relay communication, and a method thereof. According to an embodiment of the present invention, a system for performing phase detection and synchronization in an AMI communication network using a relay communication includes an AMI server for collecting a ‘reference zero-crossing detection (ZCD) time difference by phase’ of input/output terminals of a main transformer installed in a substation; and a data concentration unit (DCU) comparing the ‘reference ZCD time difference by phase’ transmitted from the AMI server with a ‘ZCD time difference by phase’ collected by itself, and matching the same to have a time difference close to an error range.