292 results about "Synchronous frame" patented technology

A method for synchronization and communication in a multi-hop network includes: transmitting a synchronization signal by a central node or a previously synchronized node, with a beacon slot assigned a beacon and the hop count value of the transmitting node transmitted in the frame of the synchronization signal, and, for all previously synchronized neighbor nodes of the transmitting node transmitting respective beacon slots and the hop count values in the frame of the synchronization; receiving by a first node the synchronization signal and the data transmitted in connection therewith; synchronizing the first node to the synchronization signal; detecting by the first node its neighbors and their respective beacon slot assignment and hop count values; determining the predecessor of the first node in the network by the first node in dependence of given criteria; storing by the first node the data received with the synchronization signal and data received in connection therewith and determined therefrom; and repetition the foregoing steps until synchronization of all the nodes.

Communication, using a synchronous protocol, over a synchronous communications link, between synchronous application programs executed on a terminal (i.e., personal computer, PC) with an asynchronous byte-oriented interface and a PC with a synchronous frame orientated interface is made possible by enhancing the PC with the asynchronous byte-oriented interface with a device which modifies the data to be transmitted by inserting framing flags and transparency characters before the data passes through the COMM port (asynchronous byte-oriented interface) and extracting the transparency characters after the data exits the COMM port. As a consequence, the PC with the frame-oriented interface does not have to be modified.

The invention discloses a dual-CCD (Charge Coupled Device) scanning imaging detection method for continuous casting slab surface defects. The dual-CCD scanning imaging detection method comprises the following steps: (1) mounting a linear array CCD camera, an area array CCD camera and a linear laser transmitter on a continuous casting slab; (2) scanning by the linear array CCD camera and the area array CCD camera according to a synchronous frame frequency and line frequency manner to obtain a two-dimensional image and a three-dimensional image of the surface of the continuous casting slab; (3) registering the acquired two-dimensional image and three-dimensional image; and (4) carrying out information fusion processing on the registered two-dimensional image and three-dimensional image in one area on the surface of the continuous casting slab, analyzing area-of-interest features of the two images, and extracting a final area-of-interest to be identified on the surface of the continuous casting slab by combining the feature fusion processing result of the two images, thus reserving reliable defect information of the surface of the casting slab and detecting the surface defects of the continuous casting slab. According to the dual-CCD scanning imaging detection method provided by the invention, the structure is simple and convenient; the method is high in detection precision, great in real-time property and capable of automatically eliminating interference information.

A method of configuring system layers for a synchronous Ethernet is provided. In the method, a physical layer takes charge of input and output of an Ethernet frame in direct relation to hardware, an xMII (x Media Independent Interface) layer connects the physical layer to a data link layer. The data link layer has a sync frame processor for processing a synchronous frame and an async frame processor for processing an asynchronous frame. A parser and multiplexer (MUX), included in the x MII layer, construct a super frame with a synchronous frame and an asynchronous frame, transmit the super frame through the physical layer, parse a received super frame into a synchronous frame and an asynchronous frame, and transmit the synchronous and asynchronous frames to the data link layer.

The invention provides a method for sending synchronization signals. The method includes the steps that the synchronization signals of each sub-band are generated corresponding to each sub-band according to the ID of a cell and the serial number of a corresponding absolute sub-band of each sub-band, wherein the synchronization signals generated by the different sub-bands are mutually different; all points of the synchronization signals of each sub-band are mapped to the time-frequency resource positions of the synchronization signals of each sub-band where the pointes are located for transmitting, wherein time-frequency resources of the synchronization signals comprise all downlink resources on the whole sub-bands in a synchronization frame. By the application of the method for sending the synchronization signals, the peak-to-average ratio of time-domain signals can be reduced.

The invention provides a high-speed continuous variable quantum key distribution system and a bit frame synchronization method thereof. The bit frame synchronization method comprises the following steps: Step one, a sender generates a set of special data used as a synchronous frame; Step two, the sender sends a coherent state to a receiver through a quantum channel; Step three, the receiver uses a balance homodyne detector to measure the displacement component of the coherent state; Step four, the receiver selects an appropriate alternate voltage determining threshold and a frame synchronization segment determining threshold to determine the synchronous frame according to structure information of the special data acquired through a classical channel in Step one; and Step five, synchronization fails if the receiver does not search the synchronous frame in the specified time, and the receiver needs to adjust the value of the alternate voltage determining threshold and the value of the frame synchronization segment determining threshold and reestablishes communication. According to the invention, the interference of external environmental factors to synchronization signals in the process of quantum key distribution can be effectively overcome, and synchronization between both sides of communication can be realized.

A method of enabling transmission of a time-critical control signal event in a sync frame period, such as a pause signal that is generated when the receive buffer of an Ethernet switch is filled with packets beyond a threshold due to congestion of uplink asynchronous data, is disclosed. To transmit time-critical information in a synchronous Ethernet system, a current transmission period is checked upon detection of a time-critical event. If the current transmission period is a sync frame period, time-critical control information is generated, inserted into the first sub-sync frame after the time-critical event, and transmitted. If the current transmission period is an async frame period, a control frame including the time-critical control information is generated and transmitted.

A method of processing a DVD bitstream includes the steps of reading the DVD bitstream, the bitstream including a sync frame. A sync window is created, the sync window being open at least during the expected timing of a sync detection signal within the sync frame. The sync pattern is detected within the sync frame and the sync detection signal is generated only when the sync pattern has been detected and the sync window is open. A DVD sync pattern detection circuit includes a sync window generator to generate a sync window signal, a sync pattern detector, the sync pattern detector generating a sync detection signal only when both a sync pattern is detected in a DVD input stream and the sync window signal is asserted. A read channel bit counter generates a read counter signal to control the sync window generator, the read channel bit counter being reset when the sync pattern detector detects the sync pattern. The read channel bit counter controls the width of the sync window signals to allow the generation of correctly timed demodulation enable signals even when the sync frames have non-standard bit lengths. The sync windows also prevent the erroneous detection of sync patterns within the data portions of the sync frames. A pseudo sync detection signal is generated when the sync pattern is corrupted or missing from the sync frame.

The invention discloses an E1 link-based bidirectional time-frequency synchronous transmission method and a master-slave device, and relates to communication technology. The method comprises the following steps that: A, a master station transmits a time synchronous frame to a slave station, records a synchronous frame packet transmitting time stamp T1 and inserts the time stamp T1 into the synchronous frame; B, the slave station receives the synchronous frame from the master station, records a packet receiving time stamp T2 and acquires the time stamp T1 from the synchronous frame; C, the slave station transmits a time delay request frame to the master station and records the time stamp T3 for transmitting the time delay request frame; D, the master station receives the time delay request frame transmitted by the slave station and records the packet receiving time stamp T4, and the master station transmits the time stamp T4 to the slave station; and E, the slave station acquires the time stamp T4, calculates line loop time delay D, master-slave time deviation and frequency deviation according to the acquired time stamps T1 to T4 so as to adjust local time and clock frequency, wherein information in each step is encapsulated to be in an E1 frame format. The method and the device have the advantages of no need of protocol conversion or cache and low expenditure, so data transmitting and receiving time delay jitter can be greatly reduced.

A control architecture for an electrical inverter includes a command limiter that is realized as a circular voltage limiter. The command limiter includes a Cartesian-to-polar converter coupled to a command source such as a synchronous frame current regulator. The Cartesian-to-polar converter provides magnitude and phase components for d-q command voltages. The command limiter further includes a magnitude limiter that limits the magnitude component to the maximum fundamental voltage component of the inverter, and a polar-to-Cartesian converter that converts the limited magnitude component and the phase component into modified d-q command voltages.

The embodiment of the invention provides an image splicing method and a system thereof; the image splicing method comprises the following steps: matching feature points are extracted from at least twopairs of synchronous frames, and the synchronous frame pairs are provided with an image overlapping region obtained by two different angles; homography matrix is solved according to the matching feature points; the homography matrix is applied to carry out image splicing to the synchronous frame pairs obtained by two different angles. In the embodiment of the invention, the matching feature points are extracted from a plurality of the synchronous frame pairs, so as to obtain a plurality of matching feature points, compared with the prior art, the matching feature points are extracted from a pair of the synchronous frame pairs, the method in the invention has representativeness, and the obtained homography matrix is reliable and accurate, thereby obtaining better image splicing effect.

A method of synchronising the reference clock of a first wireless device with a master reference clock of a second wireless device via a wireless network. The method involves transmitting, from the second wireless device to the first wireless device, a dedicated synchronisation frame via a dedicated synchronisation channel; receiving the dedicated synchronisation frame at the first wireless device; and synchronising the reference clock of the first wireless device with the master reference clock of the second wireless device based on the received dedicated synchronisation frame.

The disclosure provides a system and method for monitoring and evaluating a conversion facility. The method includes storing values for quantitative variables and/or cost variables associated with processes performed at the conversion facility. The method includes receives a syncing frame, wherein the syncing frame embraces values for the quantitative variables and/or the cost variables stored less than thirty days prior to receiving the syncing time frame. The method includes determining, from the stored values for at least one set of values for at least one of the variables that are within the syncing frame. The method also includes calculating a cost of processing a commodity processed at the conversion facility for the syncing frame using the first and second set of values.

The invention discloses a TDMA based long propagation delay wireless link time slot distribution method which is mainly used for solving the problem of low throughput rate and low channel utilization rate of an existing long propagation delay wireless ad hoc network. The implementation scheme comprises the steps of 1, initializing a node; 2, judging whether the node receives a synchronous frame, if so, carrying out network access synchronization by the node, and otherwise, building a network by regarding the local clock as a reference by the node; 3, after synchronization is finished, generating a super-frame structure automatically by the node, and dividing the local time into multiple time slots with different functions; and 4, judging whether the current time slot is a service time slot by the node, if so, sending and receiving data, and otherwise, updating network information. as the TDMA is adopted as a channel access mode, the node can access the channel without any conflict; and through an interactive sending mechanism and a data frame queue scheduling mechanism, the network throughput rate and the channel utilization rate are increased, the queuing delay of the data frames is reduced; and the TDMA based long propagation delay wireless link time slot distribution method can be used for a time division multiple access ad hoc network.

Network equipment at sending end packs several data frames received early or late into IP data packet, and sends the IP data packet to network equipment at receiving end through IP network. Data frame in IP data packet stores recorded timestamp of transmission time difference between adjacent data frames. Based on comparison between time interval of data frame received successively and data frame stored timestamp, the network equipment at receiving end determines whether the received IP data packet is transmitted out. Moreover, through types, sequence number id in IP data packet, the method determines whether reception is correct in order to decide whether to ask the sending end to do retransfer. Features are: realizing synchronous transmission of data frame, increasing use ratio of bandwidth, and raising transmission efficiency.

An LPP detection unit detects an LPP from a wobble signal. A correction unit obtains a difference set by performing processing of calculating a difference in signal level between an LPP-present sync pattern portion and a non-LPP sync pattern portion having the same polarity, and executes correction on an RF signal at a timing when the LPP is detected, by using the difference set. The LPP-present sync pattern portion is a sync pattern portion obtained when the LPP is detected at the timing of the sync pattern portion positioned at the head of a sync frame of the RF signal. The non-LPP sync pattern portion is a sync pattern portion obtained when no LPP is detected at the timing of the sync pattern portion of the sync frame. In the case of reproducing information recorded on a DVD-R/RW optical disk, the occurrence of errors due to the effect of the LPP can be reduced.

A wireless sensing network is a network structure comprising many nodes communicating with each other by wireless radio frequency mode; most of the nodes in the wireless sensing network are supplied power by cell; so the power consumption management of node is an important problem in wireless sensing network design. A radical solution to the problem is to make the nodes in sleep state with low power consumption in most time; and the node in sleep state must be able to wake synchronously to accomplish network function. The algorithm provides a synchronous mechanism, which comprises: a synchronizer exists in network for sending a synchronous frame; the synchronous frame is forwarded step by step by routers in the network to all the nodes; and the nodes in the network obtains the consistent clocks by using the synchronous frame and the synchronizer. By applying the mechanism described in the algorithm, almost all the nodes in a wireless sensing network can be supplied power by cell and can sleep periodically.