1800 results about "Interference immunity" patented technology

Apparatus and a method for enhancing the interference resistance of so-called RFID systems, wherein identification messages delivered from an identification device are longer than the time for which an anticipated interference or disturbance is calculated to continue, and wherein the messages contain redundancy, such as a checksum. The messages are delivered from the identification device repetitively, and are redundancy checked. In the event of any discrepancy in the redundancy check, such as when the checksum is checked against the data content of the message and is found in disagreement, successive messages are checked bit for bit against each other. Any deviations between otherwise previously rejected messages are assumed to be due to external interference and are thus successively substituted until the redundancy check gives an accepted result, such as through the medium of a checksum check according to the so-called CRC method.

A data transceiver module for digital data communications in a portable handheld data terminal has multiple data spread spectrum modes which include direct sequence and frequency function modulation algorithms. The transceiver module has multiple user or program configurable data rates, modulation, channelization and process gain in order to maximize the performance of radio data transmissions and to maximize interference immunity. Various module housings, which may be PCMCIA type, are able to be mated with a suitably designed data terminal. Media access control protocols and interfaces of multiple nominal operational frequencies are utilized. Wireless access devices in a cell based network each consider a variety of factors when choosing one of a plurality of modes of wireless operation and associated operating parameters. Such selection defines a communication channel to support wireless data, message and communication exchanges. In further embodiments, the wireless access devices also support a second channel, a busy / control channel, for managing communication on the main communication channel and to overcome roaming and hidden terminal problems. Roaming terminal devices are also configured to support the dual channel design. Such configuration in both circumstances may involve the use of a multimode radio that is timeshared between the two channels or two radios, one dedicated to each channel.

This invention describes a means for acquiring GPS P / Y code under jamming conditions. It improves jam resistance by augmenting a component of the GPS signal with one from a different satellite system, such as a low earth orbiting (LEO) satellite. The preferred embodiment of this invention employs the Iridium LEO satellite constellation broadcasting in a 10 MHz wide band about 1,621 MHz. A low-cost, integrated Iridium receiver coupled to the GPS receiver employs a single antenna that is capable of receiving both the GPS and Iridium signals together.

The invention discloses a train unmanned system and a train unmanned method, belonging to the field of traffic control. The system comprises a sensor, an automatic train protecting system connected with the sensor, a train-mounted recording system connected with the automatic train protecting system, an automatic train driving system connected with the automatic train protecting system, and a man-machine interaction system connected with the automatic train protecting system. By utilizing the system and the method, the precise control on the unmanned operation process of a train is realized, misoperation caused by artificial factors is reduced, the interference resistance is good, the working intensity of drivers is reduced, the security in train operation is improved, the departure interval of trains is shortened, and the operation efficiency of train routes is improved.

A data transceiver module for digital data communications in a portable hand-held data terminal has multiple data spread spectrum modes which include direct sequence and frequency function modulation algorithms. The transceiver module has multiple user or program configurable data rates, modulation, channelization and process gain in order to maximize the performance of radio data transmissions and to maximize interference immunity. Various module housings, which may be PCMCIA type, are able to be mated with a suitably designed data terminal. Media access control protocols and interfaces of multiple nominal operational frequencies are utilized. Wireless access devices in a cell based network each consider a variety of factors when choosing one of a plurality of modes of wireless operation and associated operating parameters. Such selection defines a communication channel to support wireless data, message and communication exchanges. In further embodiments, the wireless access devices also support a second channel, a busy / control channel, for managing communication on the main communication channel and to overcome roaming and hidden terminal problems. Roaming terminal devices are also configured to support the dual channel design. Such configuration in both circumstances may involve the use of a multimode radio that is timeshared between the two channels or two radios, one dedicated to each channel.

The present invention relates to employing OFDM modulation in combination with spatial diversity and space-time block coding to provide high data rates and exceptional interference immunity. For transmission, quadrature modulated data is encoded in space and time to create individual series of encoded symbols. Each of these series of encoded symbols is subjected to a type of inverse Fourier Transform in corresponding transmission paths. In each transmission path, cyclic extensions may be appended to the resultant symbols, which are subsequently converted to an analog format, modulated, amplified, and transmitted from one of multiple antennas. Preferably, such communications are implemented from base stations to mobile terminals in an environment where the frequency reuse factor is approximately one and the base stations are synchronized to a common clock signal.

The invention discloses a phase calibration method of the DQS delay for a DDR controller and an apparatus thereof. The method comprises the following steps: 1, sampling DDR data DQ according to trigger signals after different grade delays of a DQS signal; 2, comparing the data DQ acquired by sampling with a preset self-check datum in byte, and acquiring a minimum boundary delay parameter and a maximum boundary delay parameter through delaying for two beats; 3, endowing a mean value of the minimum boundary delay parameter and the maximum boundary delay parameter to a DQS selection signal; and 4, delaying the DQS signal according to the output clock of the DQS selection signal to obtain a DQS signal at the center of an effective datum window. According to the invention, the phase calibration of the DQS delay is realized through adopting a delay parameter determination unit and hardware in a delay parameter output circuit, and the delayed DQS can accurately fall on the center of the effective datum window through a datum screening method with the delay parameter determination unit, thereby the stability, the accuracy and the interference immunity of datum sampling are enhanced.

A multiple-input-multiple-output radar waveform design method belongs to the radar communication technical field, and aims to provide a design method with lower related sidelobe and frequency spectrum inhibition depth, high efficiency, less consumption, high robustness, and excellent time frequency anti-interference performance; the method comprises the following steps: pre-evaluating an autocorrelation sidelobe inhibition fuzzy region according to a relative position between a strong scatterer and a to be measured object in a radar scene, thus forming a corresponding object function; analyzing MIMO radar waveform orthogonality constraint so as to form the object function satisfying the orthogonality constraint; pre-evaluating a frequency domain interference fuzzy frequency band zone according to scene prior information, thus forming the corresponding object function; forming a constant modulus phase coding waveform constrained condition; forming a loose alternative projection algorithm framework; solving a waveform design according to the loose alternative projection algorithm framework, thus providing three waveform optimization output modes. The loose alternative projection constant modulus waveform coding design enables the MIMO radar to have batter detection performance.

The invention discloses a method and a device of remote uderwater acoustic communication. The device comprises more than one underwater communication nodes and more than one abovewater communication buoys which are responsible for communication with more than one underwater communication nodes within a set distance range through an underwater acoustic channel; and the communication connection is carried out between the abovewater communication buoys through a land wireless channel. In the method, the multi-frequency band combination is adopted to sent data in parallel, and the remote communication is realized by uniting the communication buoys; in the remote communication, a three-time handshake protocol in the carrier sense multiple access (CSMA) needs not to be used in the communicationbetween the underwater communication nodes and the buoys, while a channel can be directly monitored in a full frequency range; the data are synchronously sent to the abovewater communication buoys inparallel on each subchannel on the monitored idle channel by utilizing a frequency modulation method; and the data is transmitted by the abovewater communication buoys through a radio wave manner. Bythe method and device provided by the invention, one-time successful transmission probability of the two parties of the communication can be improved, and the anti-interference performance of a system is enhanced.