96 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.

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.

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.

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.