PLEXTEK LIMITED Patent applications |
Patent application number | Title | Published |
20100245161 | DOPPLER RADAR SYSTEMS - A frequency scanning radar system includes a controller for controlling a frequency generator and a signal processor arranged to determine a Doppler frequency associated with a target. The frequency generator generates three or more sets of signals, each set of signals having a different characteristic frequency and including signals transmitted at a selected rate, and the radar controller selects the rate in substantially direct proportion to the characteristic frequency, whereby to normalize the Doppler frequency determined by the signal processor, such that the normalized Doppler frequency is substantially constant in relation to variation in the carrier frequency. In a frequency modulated radar system, each set of signals includes a sequence of modulation patterns, and the radar controller modifies a given modulation pattern in dependence on the characteristic frequency of the signal being modulated. | 09-30-2010 |
20100195665 | DATA ACKNOWLEDGEMENT APPARATUS AND METHOD - In the sending of data in a network from a sending node to a receiving node via a relay node, the receiving node sends a notification arranged to notify both the sending node and receiving node of receipt of data at the receiving node. Notifications acknowledge that the data has been correctly received over each individual stage of transmission, and further acknowledge to the sending node that data has been correctly transmitted over the whole transmission path and received at the receiving node. The burden on the network of sending acknowledgments is reduced while notifications of data transmission over single stages and over the whole transmission path are provided. | 08-05-2010 |
20100142464 | METHOD AND DEVICE FOR SELECTING AND TRANSMITTING VARIABLE FRAME FORMATS - A network includes a first transceiving station and a further transceiving station. In one arrangement the data is transmitted from the first transceiving station to the second transceiving station according to a frame structure having a payload portion for payload data and a synchronisation portion for synchronisation data. The frame structure is selected from candidate frame structures having differing durations of the synchronisation portion, according to a data loading factor which depends on the amount of data that is required to be transmitted. The payload capacity may be optimised by reducing the duration of the synchronisation portion when a large amount of data is required to be transmitted. | 06-10-2010 |
20090304127 | NARROW BAND RECEIVER - An RF receiver comprises a signal processor arranged to perform a method of decoding data contained within a signal that comprises a set of slots, at least one said slot comprising a preamble portion and a payload portion and being transmitted at a predetermined transmission frequency. The signal processor is arranged to perform a first process to derive timing data from the preamble portion and perform a second process to extract information from the payload portion, the second process being triggered from said timing data derived from the first process. The preamble portion comprises at least a first sequence of data and a second sequence of data, and the second sequence is the inverse of the first sequence. In preferred embodiments the first process comprises identifying a transition between said first and second sequences of data and deriving said timing data from the identified transition. | 12-10-2009 |
20090303981 | NARROW BAND TRANSCEIVER - The data transmitted from a first station is transmitted at a first data rate. The data transmitted from a second station is transmitted at a second data rate. The second data rate is lower than the first data rate. In view of both the difference in data rates and the synchronisation between radio stations, a separate synchronisation word is not required to be sent from the second station to the first station on the uplink portion; instead, and because the uplink slots of a given frame are synchronised between transceiving stations, the start of the uplink payload slot can comprise signalling information which simply acts to signify the start of transmission of uplink data from the second station. | 12-10-2009 |
20090295620 | RADAR SYSTEM - Electronically steered radar systems such as frequency scanning radars are particularly suitable for detecting and monitoring slow moving, ground-based targets. So-called crawler radar systems are intended for detection of targets that deliberately attempt to avoid detection by keeping low and by moving slowly. Disclosed is a radar system which includes an electronically steered antenna and a receiver arranged to process signals received from a target located at a distance from the radar system so as to identify a Doppler frequency associated with the target. The antenna stares at, rather than glides past, the target surrounding clutter. This means that the spectral spreading of static ground clutter associated with mechanical radar systems can be eliminated, overcoming one of the shortcomings of mechanical radar systems that would otherwise render a crawler radar system unsuitable for Doppler processing. | 12-03-2009 |
20090273505 | RADAR SYSTEM - A scanning radar system suitable for detecting and monitoring ground-based targets includes a frequency generator, a frequency scanning antenna, and a receiver arranged to process signals received from a target so as to identify a Doppler frequency associated with the target. The frequency generator generates sets of signals, each set having a different characteristic frequency, and includes a digital synthesiser arranged to modulate a continuous wave signal of a given characteristic frequency by a sequence of modulation patterns to generate one set of signals. The frequency scanning antenna cooperates with the frequency generator to transceive radiation over a region having an angular extent dependent on the generated frequencies. Digital synthesiser techniques capable of precise frequency generation and control are combined with passive frequency scanning and Doppler processing techniques, enabling accurate control of range and scan rates, and optimisation of range cell size for factors such as slow and fast target detection and Signal to Noise ratio, so that targets can be detected at distances considerably farther away than is possible with known systems having similar power requirements. | 11-05-2009 |
20080284652 | FREQUENCY SCANNING ANTENNA - Embodiments of the invention are concerned with frequency scanning antennas for transceiving radio frequency energy for use in detecting and monitoring ground-based targets. | 11-20-2008 |
20080284651 | RADAR SYSTEM - Embodiments of the invention are concerned with a radar system, and relates specifically to scanning radar systems that are suitable for detecting and monitoring ground-based targets. | 11-20-2008 |
20080284641 | DOPPLER RADAR SYSTEMS - Embodiments of the invention are concerned with improvements to Doppler radar systems, and are suitable for use with frequency scanning radar systems. | 11-20-2008 |