92 results about "Syncword" patented technology

Noise is prevented when decoding an audio stream not containing syncwords or CRC bits in the elementary stream. When decoding a current frame, the private header of the next frame is analyzed and the current frame is muted if the private header of the next frame is not valid. When there is a data discontinuity caused by editing, decoding resumes from the start address of the next frame determined by the stream analyzing means.

The payloads of IP packets are checked to actually determine if a packet contains MPEG-2 video rather than using predefined streams or priority levels that are assumed to contain such information as is done in the prior art. More specifically, the “sync” bytes of the MPEG-2 stream are searched for within the IP packet payload, and when a pattern indicative of the sync bytes is found the sync bytes are identified and the packet is determined to contain MPEG-2 video. The sync byte was defined in MPEG-2 for over-the-air broadcasting in order that a television receiver be able to synchronize the MPEG-2 transport stream packets. Note that the MPEG-2 video, e.g., the MPEG-2 transport stream packets, may or may not be incorporated within real time protocol (RTP) packets before being incorporated into the IP packets.

Provided are a forming terminal of a time slot data frame compatible with a data chain and a working method of the same. Based on correlation of data redundancy and requirements for communication quality of service, under the condition of constant radio-frequency bandwidth, the terminal can visually and clearly display the formation process of the time slot data frame through the coordination of parts. The received service data is analyzed, and an appropriate encoding, a modulation, a spread spectrum combined technology and a data encapsulation formats are selected, then the combined technical information is creatively mapped to a fine synchronization field stuffing bits for the time slot data frame, so that when the receiving terminal is in the fine synchronization, the encoding, the modulation and the spread spectrum subsequent combined technical information of the subsequent received data are obtained, which can shorten the preprocessing time of the received data, satisfy the requirement of anti-interference, confidentiality, real-time and coverage of the data chain, and further enhance the adaptability of the data chain to future complex environments and improve system throughput. The forming terminal of the time slot data frame compatible with the data chain has the advantages of being compact, reasonable and artful in structure, being simple, convenient and easy to operate, and being promising in application prospect.

The embodiment of the invention provides a data retransmission method. The data retransmission method comprises the steps of receiving broadcast data transmitted by bluetooth master equipment at a preset receiving interval; detecting whether the broadcast data transmitted by the bluetooth master equipment is correctly received or not; and when it is detected that the broadcast data transmitted bythe bluetooth master equipment is not correctly received, requesting the bluetooth master equipment to retransmit the broadcast data, and receiving the retransmitted broadcast data. The embodiment ofthe invention further provides bluetooth slave equipment and a wireless communication system. The data retransmission method has an additional function of feeding back information of incorrect reception after the bluetooth slave equipment receives the broadcast data on the basis of the existing point-to-multipoint broadcast transmission mechanism. Whether there is bluetooth slave equipment requesting data retransmission or not is judged according to a relation between the bluetooth master equipment and the feedback data by using a characteristic that multiple sets of bluetooth slave equipmentsimultaneously transmit by adopting the same synchronization word on the same channel, thereby realizing automatic retransmission, and thus improving the reliability of point-to-multipoint broadcast transmission.

A method and apparatus for searching the synchronization signal of a next frame in encoded digital signal without the need of referring to a frame length indication signal. The encoded digital signal contains a plurality of frames, wherein each frame may have varying length and contain a synchronization signal. The method includes determining a search region, and locating the synchronization signal in the search region.

A predetermined syncword detecting circuit includes a matched-bit-number comparing circuit, a comparing-result-change detecting circuit, a detected-result storing circuit, a total number detecting circuit, and a syncword detecting circuit. The matched-bit-number comparing circuit acquires a number of bits in a baseband signal that matches bits of the predetermined syncword and compares the number with a first threshold. The comparing-result-change detecting circuit samples the result of the matched-bit-number comparing circuit. The comparing-result-change detecting circuit detects changes in the result of the matched-bit-number comparing circuit. The detected-result storing circuit sequentially stores a result of the comparing-result-change detecting circuit. The total-number detecting circuit detects a total number of the result of the matched-bit-number comparing circuit. The result is included in an N cycle period and surpasses the first threshold. The syncword detecting circuit detects the predetermined syncword and selects an intermediate phase of the cycles as a detection phase.

Method and computer program product are provided to encode data for recording onto media whereby modulation and linear constraints from a concatenated code or product code are imposed. A first array of unencoded user data is generated. Each row is modulation encoded to enforce a first modulation constraint; the array is transformed into a second array which is transformed into a third array having predetermined empty locations in each column interleaved with the modulated data. A C2-parity byte is computed for at least some of the empty locations of the third array and a fourth array is generated. C1-parity symbols in each row are computed, generating a fifth array. A second modulation constraint is enforced on each C1-parity symbol in each row of the fifth array, generating a sixth array. The rows of the sixth array are assembled with header and sync fields for recording onto a recording media.

A frame synchronization apparatus and method based on differential correlation in a communication system are provided. A correlation analysis is performed by using sync word in a prior search window and a posterior search window for obtaining a plurality of prior-window correlation values and a plurality of posterior-window correlation values, respectively. N maximum correlation values in the correlation values are selected, wherein indexes of the maximum correlation values are I₁˜I_N, and N is an integer greater than 0. The posterior-window correlation values are compared with a first threshold. If one of the posterior-window correlation values is greater than the first threshold, the index of the one is defined as J. If the index J is equal to one of the index I₁˜I_N, a check step is performed by using the index J for confirming that a position of the index J is a header position.

The invention provides a space link protocol blind identification method and system. The space link protocol blind identification method comprises the steps that target data in a file to be blind identified are converted into hexadecimal data; all frequent sequences within an appointed length range are found based on the hexadecimal data to constitute an initial frequent sequence set, and statistics is performed on the number of occurring times of the sequences of each appointed length; count values of the frequent sequences obtained by the statistics are compared with a plurality of set min_threshold values one by one, and the frequent sequences of which the count values are larger than the min_threshold values are stored in a middle frequent sequence set; a pattern matching method is adopted, all sequences in the middle frequent sequence set are searched for and positioned in the target data one by one, all equally-spaced frequent sequences are extracted from the middle frequent sequence set, and a target frequent sequence set is constituted; pattern matching is conducted on the target frequent sequence set obtained by excavation and space link protocol frame synchronization word sensitive information, and applied protocol types are judged.

The invention provides a data link anti-quantum computing communication method and system based on ID cryptography and a symmetric key pool. The method comprises the following steps: firstly, allocating respective identity IDs and private keys to two communication parties through an ID cryptography mechanism, calculating opposite side public keys by the two communication parties respectively by utilizing the IDs disclosed by the opposite sides, and calculating symmetric keys according to the own private keys and the opposite side public keys; when the two parties with the symmetric key communicate with each other, enabling asender and areceiver to perform frequency hopping synchronization through adoption of a synchronization header method, and appoint to select at least one part of information in the synchronization header as initial information; enabling the initial information to besubjected to root key transformation by a key pool, so that the initial information acquired by the enemy becomes useless information; and then, based on a true random number key sequence in three links of root key calculation information encryption and message authentication, direct sequence spread spectrum and frequency hopping which cannot be obtained by an enemy, achieving anti-quantum calculation of data transmission, and therefore the security of the whole data link system is greatly improved.

The invention discloses a method and device for five times of iterative decoding of superstrong forward error correction, and relates to the field of channel error correction coding and decoding in an optical communication system. The device comprises a synchronization word analytical unit, an internal frame mapping unit, an RAM storage unit, a control unit for five times of iterative decoding, a BCH (900, 860) code syndrome computing unit, a BCH (900, 860) code BM algorithm unit, a BCH (900, 860) code data buffer unit, a BCH (900, 860) code forward search and error correction unit, a BCH (500, 491) code syndrome computing unit, a BCH (500, 491) code data buffer unit, a BCH (500, 491) code forward search and error correction unit, an internal frame inverse mapping unit and a decoding performance monitoring unit. Hardware implementation resources are small in scale, and the good coding gain error correction performance is acquired through five times of iterative decoding.

A hopping spread-spectrum wireless network for IoT applications. The network includes mobile devices with unsynchronized local clocks that transmit including, in a preamble portion, a plurality of sync words, each combined with at least one instance of a sequential index. The hopping frequencies at which the sync word are transmitted are different. This arrangement helps detection and synchronization of the signals, despite the unavoidable frequency mismatches and collisions.

The invention relates to the technical field of satellite positioning, and discloses a GNSS receiver long-time lock loss recapture rapid recovery positioning method, which is characterized by comprising the following steps: S1, when a satellite signal receiver locks a satellite signal, storing locking state data; S2, traversing each channel of the satellite signal receiver in each traversing period, judging whether a satellite signal is unlocked or not, if so, continuing S3, and otherwise, continuing S2; S3, the satellite signal receiver carrying out lock losing counting to obtain lock losingtime, when the lock losing time is within a first threshold value, continuing the step S4, and otherwise, kicking off a lock losing channel; and S4, after recapturing the satellite signal, speculatinga frame synchronization word in combination with the locked state data, and resolving a positioning result of the satellite signal receiver by utilizing the frame synchronization word. The speculatedframe synchronization words can directly participate in positioning calculation, and the steps of bit synchronization and frame synchronization are omitted, so that the positioning result is quicklyobtained.

The invention discloses a method for solving a multi-portrait label job-oriented scheduling task, which belongs to the technical field of system development and comprises the following steps of: 1, acquiring data required by a user portrait and taking the data as a source end of offline data scheduling; 2, synchronizing fields into a hive data warehouse; 3, checking the number of source end data and the number of data synchronized into the portrait intermediate table, if the number of source end data is consistent with the number of data synchronized into the portrait intermediate table, starting a scheduling job of offline label data, calculating the offline label data of the user portrait, and if the number of source end data is not consistent with the number of data synchronized into the portrait intermediate table, deleting the synchronized data of the day and rescheduling; and 4, checking whether the calculated offline label data is normal, if not, sending a mail and enterprise WeChat to inform related personnel, and if yes, starting a scheduling task of aggregating the user label data. According to the method, the required label can be automatically generated, rescheduling and mail notification sending are carried out when the task goes wrong, and the reliability and stability of data are ensured.

The invention discloses a frequency hopping group call delay adding method suitable for PDT/DMR, and belongs to the technical field of wireless communication. After a calling party initiates establishment of a frequency hopping group calling service, a transmitting party alternately embeds frequency hopping synchronization information subjected to link coding and link control signaling into an embedded information domain of a part of subframes of a voice superframe; after the equipment which is not in the group calling service is transferred to the group, the equipment is in a slow scanning state on the service frequency point sequence; after receiving the complete service superframe, the receiver firstly determines a burst position according to a synchronization word in the service superframe, and then extracts frequency hopping synchronization information embedded into the voice sub-frame; the receiver shifts to a synchronous following hopping state according to the frequency hopping synchronization information to realize synchronous receiving; and after the superframe carrying the link control signaling is synchronously received, the group call service is added according to the information in the link control signaling. According to the invention, on the basis of not changing PDT/DMR communication system air interface waveform, a frequency hopping group call delay adding function can be realized.