Abstract: GPS aided precision timing uses GPS to generate synchronized timing pulses by various nodes. One of the nodes is designated as a master node and the remaining nodes are designated as auxiliary nodes. Each node tracks the carrier phases of satellite signals transmitted by a plurality of GPS satellites relative to a carrier phase of a reference oscillator in the respective node. The master node provides the tracked phase measurements along with its position information to all of the auxiliary nodes. Each auxiliary node determines the phase offset of its reference oscillator relative to the reference oscillator of the master node to “align” its phase to the phase of the master node. The phase of a time pulse signal generator in each node is then aligned to the phase of its reference oscillator for generating synchronized timing pulses based on the aligned phases.

Abstract: Space-time solutions are determined by exchanging pings among nodes in a network. Each ping includes a current space-time state of the transmitting node, which includes the transmitting node's currently estimated location and corrected time (as a count stamp). A particular node in the network receives pings from the other nodes in the network and uses the data in the received pings to estimate its own current position and to correct its own free-running clock relative to a common system time. As a service to the network, the particular node then transmits its corrected time (as a count stamp) and estimated position to the other nodes. In some embodiments, the space-time solutions discussed herein are used as backup to other navigation systems, such as the Automatic Dependent Surveillance-Broadcast (ADS-B) system.

Abstract: A clock synchronization method, apparatus, and system are provided according to the embodiments of the present invention. The method includes: receiving time information TM1 from a central office side, in which the time information TM1 is obtained by the central office side by reading a local clock of the central office side when transmission data at a first designated location starts to be transferred, and the local clock of the central office side is synchronous with a Global Positioning System (GPS) clock or a Building Integrated Timing Supply (BITS) clock; determining whether transmission data at a second designated location starts to be received, if so, reading a local clock of the Customer Premises Equipment side to obtain time information TS1; and synchronizing a clock frequency of the Customer Premises Equipment side to the central office side according to the time information TM1 and the time information TS1.

Abstract: A wireless device receives a message assigning each second carrier to one of a first carrier group and second carrier group(s). The message comprises parameters for each second carrier. If the parameters comprise a carrier group index for a second carrier, the second carrier is assigned to one of the second carrier group(s) identified by the carrier group index. Otherwise, the second carrier is assigned to the first carrier group. The wireless device receives a time alignment command comprising the carrier group index and a time adjustment value.

Abstract: A data source sends a synchronization signal and information to several data sinks that use the synchronization signal and a specified parameter to determine when to process the information. The data source and data sinks may comprise wireless nodes such as, for example, a wireless audio source that sends multi-channel data to a pair of wireless earpieces. The wireless earpieces use the synchronization signal and a latency interval to determine the appropriate time to output audio based on the audio channels.

Abstract: A bidirectional wireless communication system includes: a first wireless communication apparatus for bidirectional communication configured to multiplex a modulated signal obtained by modulating an input signal by a reference carrier signal having a predetermined carrier frequency, and transmit a resultant transmission signal; and a second wireless communication apparatus, having an oscillator configured to oscillate a signal having a free-running oscillation frequency, configured to inject a reception signal received from the first wireless communication apparatus into the oscillator, receive the reception signal while variably controlling the free-running oscillation frequency of the oscillator of the second wireless communication apparatus, detect whether the free-running oscillation frequency of the signal of the oscillator of the second wireless communication apparatus has entered the frequency range up to the injection locking to be frequency-locked with a carrier frequency of the injected reception sig

Abstract: A base station configures a first carrier group and a second carrier group in a wireless device. The wireless device transmits first uplink signals in the second carrier group employing a first secondary carrier in the second carrier group as a timing reference carrier. The wireless device autonomously changes the timing reference carrier to a second secondary carrier in the second carrier group. The second secondary carrier is an active carrier different from the first secondary carrier. The wireless device transmits second uplink signals in the second carrier group employing the second secondary carrier as the timing reference carrier.

Abstract: Aspects of the present disclosure are also directed towards a method that includes maintaining a transmission period which has a start time and an end time synchronized to metrological time. Further, this method, in response to the start time, begins transmission of a frame, which includes a plurality of symbols. This transmission occurs over power distribution lines that carry power using alternating current (AC). This method also includes synchronizing a transmission time for each symbol of the plurality of symbols according to a time-based parameter of the AC. In response to reaching an end of the frame, a synchronization symbol period is determined for a synchronization symbol, as a function of the transmission times, for the plurality of symbols and time from the end of the frame to the end time. The synchronization symbol is then transmitted on the power distribution lines.

Abstract: In some embodiments, a system comprises a clock, a root node, a radio channel network, and first and second child nodes. The clock may be configured to generate a clock signal. The root node may be configured to generate a first frame including a first payload and a first overhead and generate a second frame including a second payload and a second overhead. The first and second overheads may comprise a synchronization value based on the clock signal. The radio channel network may be in communication with the root node for transmitting the first and second frames. Each first and second child nodes may be configured to perform clock recovery including frequency synchronization using the synchronization value and a respective phase-lock loop.

Abstract: Region having a same size in a audio signal region of a transmission frame is allocated to each of an active engine and passive engine. The active engine reads out input signals written into regions of the frame, performs signal processing on the read-out signals, and writes resultant signals into the region allocated to the active engine. The passive engine reads out the input signals written into the regions, performs the same signal processing as the active engine on the read-out signals, and writes resultant output signals into the region allocated to the passive engine. When a flag of the active engine is indicative of a normal state, an output device reads out the output signals from the region allocated to the active engine, but, when the flag is indicative of an abnormal state, the output device reads out the output signals from the region allocated to the passive engine.

Abstract: Precision Timing Protocol (PTP) related functions for use in packet communications carried in part by a microwave communications link include setting of time of day values across the microwave link and providing transparent clock functions. The PTP functions may be used for synchronizing radio base stations in a cellular network. The transparent clock can bridge Ethernet switches associated with microwave stations providing the microwave communications link.

Abstract: RFID tags are used for many purpose including tracking. RFID interrogators are used to retrieve information from tags. In many applications, a plurality of RFID interrogators are required. Synchronization between interrogators in the same theatre of operation is critical to ensure that their broadcasts do not interfere with each other. In fixed RFID interrogator applications, RFID interrogators can be wired together allowing a channel to synchronize the transmissions of the RFID interrogators. Methods described herein can ensure that synchronization is maintained in the event of the failure of a synchronizing master. Furthermore, additional methods for synchronizing RFID interrogators in wireless applications are described allowing synchronization in the absence of wired connections between interrogators.

Abstract: A device and method for time synchronization in a communication network, wherein a virtual clock is produced by a controller in each network node based on the PROFINET-Standard and/or the Precision Transparent Clock Protocol. In contrast to known methods for estimating the time, the time of the virtual clock does not undergo sudden changes. The virtual clock includes a controlled, continuous path. As a result, the virtual clock is particularly suitable for time-critical applications. Here, the estimation of the time of a reference clock is improved by 18-35%. Accordingly, a markedly greater number of network nodes may be synchronized with a predetermined level of accuracy for the time synchronization.

Abstract: An efficient synchronization procedure applicable to mesh WLAN based on the 802.11s standard is proposed. A first and second stations initiate the process and establish a communication link between them. Next, the first station transmits to the second station a synchronization element that contains: a capability information element indicative of a capability of the first station to synchronize, and a status information element indicative of whether the first station has established a synchronized peer link with another station. One of the two stations may then initiate the actual handshake for synchronization. The initiator transmits a request for synchronization and receives a response from the other station representative of the acceptance by the other station of the synchronization, the request and the acceptance being restrained in that the stations may not entertain conflicting synchronization procedures with different links. The request may include a set of the synchronization profile.

Abstract: The invention relates to a method for transmitting a clock rate on a network link, seat of a speed timing signal (DR), consisting of at least synchronizing (A), at an input point (I) of this network, this speed timing signal with a reference external clock rate (ESR) for generating a synchronized speed timing signal (SDR) propagating on the network, and of extracting, at an output point (O) of the network, the reference external clock rate (ESR) from the synchronized speed timing signal (SDR) for utilization. The invention is for providing networks that are seats of a speed timing signal such as FastEthernet and Gigabit Ethernet networks or of higher speed Ethernet networks.

Abstract: When data is disclosed to a plurality of users by using a transfer network and a transfer apparatus, data disclosure time control which cannot be adversely affected by the users is performed to reduce the difference in data disclosure time among the users. A transfer network system includes a distribution server serving as a data-distribution-source transfer apparatus, and a network terminal connected to distribution-destination user equipment. The distribution server and the network terminal each have a time keeping function and a time synchronization function for matching the time of the time keeping function with a master clock. The distribution server sends in advance disclosure data and disclosure time to the network terminal. When the time of the time keeping function of the network terminal matches the disclosure time, the network terminal sends the disclosure data to the user equipment.

Abstract: An enhanced base station and clock synchronization method are provided. The method includes scanning to discover a satellite transmitting a satellite signal and a master base station providing clock synchronization signal, entering, when a satellite having a signal that fulfills predetermined conditions is found, a master mode for receiving the satellite signal to acquire clock synchronization and transmitting a clock synchronization signal to at least one slave base station, and entering, when no satellite having a signal that fulfills the predetermined conditions is found, a slave mode for receiving the clock synchronization signal from the master base station to acquire clock synchronization. The method allows the base station to switch between the master and slave modes dynamically according to variation of the communication environment, resulting in efficient clock synchronization.

Abstract: A configurable decoder within a receiver (for example, within a wireless communication device) includes numerous decoders. In one mode, the multiple decoders are used to decode different sub-packets of a packet. When one decoder completes decoding the last sub-packet assigned to it of the packet, then that decoder generates a packet done indication. A control circuit receives the packet done indications, and when all the decoders have generated packet done indications then the control circuit initiates an action. In one example, the action is the interrupting of a processor. The processor responds by reading status information from the control circuit, thereby resetting the interrupt. End-of-packet markers are usable to generate packet done indications and to generate EOP interrupts. Similarly, end-of-group markers are usable to generate group done indications and to generate EOG interrupts. The decoder block is configurable to process sub-packets of a packet using either one or multiple decoders.

Abstract: Assuring acquisition of symbol timing in a full-duplex data transceiver under inter-symbol interference conditions. One embodiment includes a transmitter comprising a first local clock having a first free running frequency, and a receiver comprising a second local clock having a second frequency initially set to a value higher than the first free running frequency. A first type decision-directed timing recovery mechanism is intentionally limited to only decreasing the frequency of the second local clock. A second type decision-directed timing recovery mechanism is not limited to only decreasing the frequency. The receiver receives symbols, decrease the frequency of the second local clock to a third frequency value using the first type decision-directed timing recovery mechanism, disables the first type mechanism after reaching the third frequency, and then phase-lock the second local clock to the optimal phase under MMSE criteria using the second type decision-directed timing recovery mechanism.

Abstract: A method and apparatus for enabling a radio to track channel timing and support channel scanning A non-leading radio operating on a communications channel, determines a diffusion period during which channel timing is to be propagated from a leading radio to non-leading radios operating on the communications channel. The non-leading radio implements a first scanning pattern during the diffusion period to scan a CT designated channel for a control timing message with a timing signal sent from the leading radio. The first scanning pattern involves scanning the CT designated channel during every other scan interval and scanning non-priority channels and priority channels during scan intervals not used on the CT designated channel.

Abstract: A method and system of applying modulated carrier signals to tree networks and processing signals tapped from the tree networks to generate output signals with phase-synchronized carriers are disclosed.

Abstract: A wireless device receives a control command to transmit a random access preamble on a second carrier. The wireless device repeatedly transmits the random access preamble until a random access response corresponding to the random access preamble is received or a predefined number of transmissions is reached. If the predefined number of transmissions is reached without receiving the random access response, the wireless device keeps an RRC connection with the base station active.

Abstract: A correlation calculating method of correlating a received code signal obtained by demodulating a received signal, which is a signal obtained by receiving a positioning satellite signal, with a replica code signal is provided which includes: correlating values of the replica code signal in a chip period with values of the received code signal at first to n-th arrival times obtained by varying an arrival time of the chip period by 1/n chip (where n is an integer equal to or greater than 2); and acquiring a correlation calculation result at a 1/n chip interval by synthesizing the correlation calculation results.

Abstract: The present disclosure is directed to a system and method for serializing data streams. In some implementations, a device includes a sapphire substrate and an integrated circuit formed on the sapphire substrate. The integrated circuit is configured to receive a plurality of digital signals from a detector and successively multiplex the plurality of digital signals to generate a serialized signal with a data rate approximately 4 Gb/s or greater, the integrated circuit having a feature size of approximately 0.10 ?m or greater.

Abstract: A wireless device receives RRC message(s) configuring transmissions of sounding reference signals on a second carrier in a second carrier group. The wireless device receives a random access response comprising a long time alignment value and a preamble identifier. The wireless device transmits the sounding reference signals on the second carrier after adjusting uplink transmission timing of the second carrier group. The wireless device is configured to not transmit any of the sounding reference signals on the second carrier until the wireless device receives the random access response comprising the long time alignment value and an uplink grant.

Abstract: A communication system including a phase-locked loop, a signal division controller, a divider, and a transmitter. The phase-locked loop is configured to generate an output signal in response to a common reference clock signal. The output signal is in phase lock with the common reference clock signal. The signal division controller is configured to receive a select signal, select an edge of a rising edge of the output signal and a falling edge of the output signal in response to the select signal, and generate a divider reset signal in response to the selected edge. The divider is configured to generate a communication clock signal by performing frequency division of the output signal. The divider reset signal controls a start time of the frequency division. The transmitter is configured to operate in response to the communication clock signal.

Abstract: A wireless device receives RRC message(s) configuring transmissions of sounding reference signals on a second carrier in a second carrier group. The wireless device receives a random access response comprising a long time alignment value and a preamble identifier. The wireless device transmits the sounding reference signals on the second carrier after adjusting uplink transmission timing of the second carrier group. The wireless device is configured to not transmit any of the sounding reference signals on the second carrier until the wireless device receives the random access response comprising the long time alignment value and an uplink grant.

Abstract: Some demonstrative embodiments include devices, systems and/or methods of clock distribution. For example, a device may include a plurality of wireless communication units including at least a first wireless communication unit, which includes a first clock source to generate a first clock signal, and a second wireless communication unit, which includes a second clock source to generate a second clock signal, wherein the plurality of wireless communication units are to switch between commonly using the first clock signal as a common master clock signal and commonly using the second clock signal as the common master clock signal.

Abstract: A clock generation device provided for a transmitter is provided and comprises a clock generator, a calculator and a first phase locked loop (PLL) circuit. The clock generator generates a first clock signal. The calculator calculates a frequency difference between the first and second clock signals. The first PLL circuit generates an output clock signal according to a first reference clock signal related to the first clock signal, and a frequency of the output clock signal is changed according to the frequency difference. The transmitter transmits data according to the output clock signal.

Abstract: A system and method for synchronizing a plurality of receivers. A tone from a signal generator is swept over a frequency band. A power splitter splits the tone into a plurality of resultant tones that are supplied to the respective receivers. For each receiver, a relative frequency response (including amplitude and phase responses) is measured between the receiver and a master receiver. A linear approximation to the phase response is computed. A digital filter is custom designed for the receiver to compensate for non-uniformity of the amplitude response and for deviations of the phase from the linear approximation. After applying the digital filter, further adjustments are made to remove the time delay corresponding to the linear approximation, e.g., by appropriately configuring a fractional resampler, by adjusting a numerically-controlled oscillator, and/or, by adjusting sample clock phase.

Abstract: A communication system and method is provided herein for synchronizing a plurality of network nodes after a network lock condition occurs within a network. According to one embodiment, the method may generate a local trigger signal simultaneously at each of the plurality of network nodes by compensating for unique phase delays attributed to each of the plurality of network nodes. As described herein, the local trigger signals may be used for synchronizing devices, such as multimedia devices, which may be coupled to the network nodes. More specifically, the local trigger signals may be used to synchronize events occurring within devices, which are coupled to different nodes of the network.

Abstract: A transmitter system including: a bidirectional signaling (BDS) network having first and second networks for carrying first and second carrier signals, and having a set of n phase synchronous location pairs (ai, bi); and also including tunable transmitter circuits for driving an antenna array, each tunable transmitter circuit having an output line for carrying an output signal and first and second input lines electrically connected to the first and second networks of the BDS network at locations of a corresponding one of the set of phase synchronous location pairs, and including a multiplier having a first input electrically connected to the first input line of that tunable transmitter circuit; a phase setting circuit electrically connected to the multiplier for controlling the phase of the output signal of that tunable transmitter circuit; and an amplitude setting circuit for controlling the amplitude of the output signal of that tunable transmitter circuit.

Abstract: An arrangement for synchronizing a transmission time of a digital data stream in individual high-frequency transmitters of a common-wave network operating according to an ATSC standard and transmitting identical data at an identical frequency. The stream generated in a master station is supplied to the transmitters as a periodic succession of data frames, and a setpoint transmission time is calculated in the transmitters from a synchronizing time stamp inserted into the data frames within the master station and from a time reference used in the master station and transmitters, while the transmission of the frames by the transmitter is determined by a system clock in the transmitters. The setpoint transmission time is compared with the actual transmission time determined by the clock, and the clock frequency is regulated by a regulating circuit so that the actual transmission time determined by the clock corresponds with the calculated setpoint transmission time.

Abstract: A medical sensor system comprises a gateway comprising a wideband receiver and a narrow band transmitter, the each gateway configured to receive a wideband positioning frame using the wideband receiver from one or more wearable sensors and to transmit acknowledgement frames using the narrow band transmitter that include timing and control data for use by the sensors to establish timing for transmission of the positioning frame; and at least one wearable sensor comprising a wideband transmitter and a narrow band receiver, the sensor configured to transmit a sensor data frame to the gateway using the wideband transmitter and to receive an acknowledgement frame from the gateway using the narrow band receiver, extract timing and control information from the frame, and adjust the timing and synchronization of the wideband transmitter using the timing and control information.

Abstract: In one embodiment, a method includes determining pre-calculated information. The pre-calculated information is used to determine a counter pattern for a reference clock. The counter pattern include, for at least one data bit, a number of reference clock cycles of the reference clock that is determined based on a frequency of the reference clock and a data rate of a serial data stream. The serial data stream is sampled to read a plurality of data bits based on the counter pattern. A data bit is sampled based on the number of reference clock cycles associated with the data bit.

Abstract: Embodiments allow for the use of the SS modulation technique (and thus for significant reduction of EMI due to clock transmission) in scenarios involving tight synchronization requirements between two devices. In particular, embodiments can be used in high-speed communication networks (e.g., high-speed Ethernet) where a clock signal embedded in the data stream at the transmitter and recovered from the data stream at the receiver is the only source for synchronization between the transmitter and the receiver (i.e., no other synchronization channel available). Embodiments are also especially useful in communication systems utilizing echo cancellers.

Abstract: A method of operation of a network system including a network line terminal coupled to a slave network unit and a master network unit over a first network includes: calculating a master round trip time between the network line terminal and the master network unit; sending a master message to the slave network unit, the master message having the master round trip time and a master local time; and calculating a slave local time based on the master round trip time and the master local time.

Abstract: A method and system for optimizing data throughput in a Bluetooth communication system is provided. The method may include determining the bit error rate (BER) of a first Bluetooth packet type of a plurality of Bluetooth packet types transmitted at a first power output level by a Bluetooth transmitter and selecting a second packet type from the plurality of Bluetooth packet types in response to determining the bit error rate. The different packet types may comprise DM1, DM3, DM5, DH1, DH3, DH5, HV1, HV2, HV3, 2DH1, 2DH3, 2DH5, 3DH1, 3DH3, and 3DH5 Bluetooth packets. The method may also include estimating the BER from the packet error rate (PER) of the first Bluetooth packet type, where the PER may be computed by comparing a number of packets of said first Bluetooth packet type with good CRCs to a number of packets of said first Bluetooth packet type with bad CRCs.

Abstract: An arrangement for providing synchronization between a number of overlapping area access points within a wireless LAN utilizes a Power over Ethernet (PoE) cable connection to transmit synchronization signals from a centralized hub/switch to each of the access points connected to the cable. The synchronization signal takes the form of a direct sequence spread spectrum (DS-SS) signal that is coupled onto the twisted pair used to provide the low voltage PoE signal to various powered devices. At each access point, a filter is used to remove the synchronization signal from the PoE transport, allowing for the group of access points to share a common beacon signal and allow for frequency re-use among the access points. The DS-SS signal is preferable created by a combination of a baseband signal and a set of separate pseudo noise (PN) sequences defining a precision phase (“pilot tone”) signal, a time mark (superframe/beacon) signal, and a time-of-day (real-time clock) signal.

Abstract: A clock recovery apparatus includes a mask generator configured to generate a plurality of time masks using a multi-phase clock signal and a clock recovery unit configured to select one of the time masks to recover a clock from a data stream.

Abstract: A method, telecommunication apparatus, and electronic device detect a status of a radio link. A transceiver 302 may receive a reference signal transmitted from a base station 104. A processor 304 may assume a transmission of a codeword of a first payload type from the base station and may determine a synchronization status based on the received reference signal and based on the assumed transmission of the codeword of the first payload type from the base station.

Abstract: Disclosed is an apparatus and methodology for synchronizing data received at a central location that has been collected at plural remote locations and separately transmitted to the central location. A plurality of remote sensors is provided and configured to be simultaneously triggered to begin a data collection sequence and to subsequently transmit the collected data along with remote sensor identification data and timing information to the central location. Timing information may include a specifically transmitted time reference or may be derived based on successive transmissions from the individual remote sensors.

Abstract: The present application discloses a method in which a base station transmits a reference signal sequence in a wireless communication system. In detail, the method comprises the steps of: generating a pseudo-random sequence using a first m-sequence and a second m-sequence; generating the reference signal sequence using the pseudo-random sequence; and transmitting the reference signal to a mobile station via antenna ports different from one another. The second m-sequence has an initial value containing parameters for discriminating reference signal sequences among users.

Abstract: In some embodiments, a system comprises a clock, a root node, a radio channel network, and first and second child nodes. The clock may be configured to generate a clock signal. The root node may be configured to generate a first frame including a first payload and a first overhead and generate a second frame including a second payload and a second overhead. The first and second overheads may comprise a synchronization value based on the clock signal. The radio channel network may be in communication with the root node for transmitting the first and second frames. Each first and second child nodes may be configured to perform clock recovery including frequency synchronization using the synchronization value and a respective phase-lock loop.

Abstract: A communication system includes master host unit, hybrid expansion unit, and remote antenna unit. Master host unit communicates analog signals with service provider interfaces. Master host unit and hybrid expansion unit communicate N-bit words of digitized spectrum over communication link. Hybrid expansion unit converts between N-bit words and analog spectrum. Hybrid expansion unit and remote antenna unit communicate analog spectrum over analog communication medium. Remote antenna unit transmits and receives wireless signals over air interfaces. Master host unit includes master clock distribution unit that generates digital master reference clock signal. Master host unit communicates digital master reference clock signal over communication link. Hybrid expansion unit receives digital master reference clock signal from master host unit over communication link and generates analog reference clock signal based on digital master reference clock signal.

Abstract: Embodiments of a synchronization circuit are described. This synchronization circuit includes multiple selectively coupled synchronization stages which are configurable to synchronize data and control signals between a first time domain and a second time domain, where the synchronization can be performed based on asynchronous or synchronous events associated with either the first time domain or the second time domain. Additionally, the synchronization circuit includes control logic, coupled to the synchronization stages, which is configured to adapt a number of synchronization stages used to synchronize the data and the control signals based on an estimate of a probability of metastability persisting to an output of the synchronization circuit during the synchronization.

Abstract: A high-speed security device for network connected industrial controls provides hybrid processing in tandem hardware and software security components. The software security component establishes state-less data identifying each packet that requires high-speed processing and loads a data table in the hardware component. The hardware component may then allow packets matching data of the data table to bypass the software component while passing other non-matching packets to the software component for more sophisticated state analysis.

Abstract: A hierarchical wireless access system includes terminals, access points, centralized access gateways and a plurality of master access point management units located at the access layer and adopting distributed architecture. The master access point management unit includes a communication interface interacting with the centralized access gateway and/or core networks, to which one or more access points are attached. The master access point management unit processes forwards the data and signaling among the attached access points, and provides the function of access gateway and local operation maintenance and network management. Construction of the master access point management unit and the access point in the system is also provided.

Abstract: A method and system of applying modulated carrier signals to tree networks and processing signals tapped from the tree networks to generate output signals with phase-synchronized carriers are disclosed.

Abstract: Embodiments of the present invention relate to systems and methods for distributing an intentionally skewed optical-clock signal to nodes of a source synchronous computer system. In one system embodiment, a source synchronous system comprises a waveguide, an optical-system clock optically coupled to the waveguide, and a number of nodes optically coupled to the waveguide. The optical-system clock generates and injects a master optical-clock signal into the waveguide. The master optical-clock signal acquiring a skew as it passes between nodes. Each node extracts a portion of the master optical-clock signal and processes optical signals using the portion of the master optical-clock signal having a different skew for the respective extracting node.