摘要:
A wide-band overlay sequence generator adds an overlay signal to a television signal which is transmitted through a channel. At a receiver, a replica of the transmitted overlay sequence is generated and synchronized to the overlay signal in the received signal. An adaptive equalizer filter effectively adjusts the received television signal so that the channel perturbations are removed from the signal.
摘要:
A spread spectrum communications system that is operable to provide user-selectable data transfer rates comprises a user station for generating an access request and a gateway server for receiving the access request. The gateway server includes a rate unit for comparing a requested rate to assigned rates, a selector for selecting an available user channel and an available signaling alphabet, and an allocation unit for assigning the carrier, user channel, and alphabet to the access request. One of several offered transfer rates is assigned to the available user channel. Each offered rate corresponds to a set of signaling alphabets with low cross-correlation for data transfer.
摘要:
A system for directing a receiving lobe of an adaptive antenna array toward an aircraft in flight includes an aircraft position vector calculator and an antenna weight vector generator. The aircraft position vector calculator receives aircraft position information from an aircraft tracking service and calculates, based upon the aircraft position information it receives, an aircraft position vector g. An antenna weight vector generator receives the aircraft position vector g from the aircraft position vector calculator and generates, based upon the aircraft position vector g, an antenna element weight vector w. The antenna weight vector w is applied to the elements of an adaptive antenna array to direct a receiving lobe of the array towards an aircraft in flight.
摘要:
A telemeter for telemetry of diagnostic messages from a mobile asset to a remote station comprises a processor coupled to the output of one or more condition sensors. The processor converts the output of the condition sensors to a diagnostic message, and provides the diagnostic message at a processor output. A transmitter is coupled to the processor output. The transmitter is adapted to transmit the diagnostic messages in the Industrial, Scientific, Medical (ISM) frequency band. An exemplary embodiment of a telemetry system of the invention comprises a telemeter adapted to transmit diagnostic messages in the ISM frequency band, and a remote station including a receiver for receiving the diagnostic messages in the ISM band.
摘要:
A system for directing a receiving lobe of an adaptive antenna array toward an aircraft in flight includes an aircraft position vector calculator and an antenna weight vector generator. The aircraft position vector calculator receives aircraft position information from an aircraft tracking service and calculates, based upon the aircraft position information it receives, an aircraft position vector g. An antenna weight vector generator receives the aircraft position vector g from the aircraft position vector calculator and generates, based upon the aircraft position vector g, an antenna element weight vector w. The antenna weight vector w is applied to the elements of an adaptive antenna array to direct a receiving lobe of the array towards an aircraft in flight.
摘要:
A telemeter for telemetry of diagnostic messages from a mobile asset to a remote station comprises a processor coupled to the output of one or more condition sensors. The processor converts the output of the condition sensors to a diagnostic message, and provides the diagnostic message at a processor output. A transmitter is coupled to the processor output. The transmitter is adapted to transmit the diagnostic messages in the Industrial, Scientific, Medical (ISM) frequency band. An exemplary embodiment of a telemetry system of the invention comprises a telemeter adapted to transmit diagnostic messages in the ISM frequency band, and a remote station including a receiver for receiving the diagnostic messages in the ISM band.
摘要:
A method for decoding (voice)data where the data is encoded by a finite-state data encoder (216) for transmission over a data channel (18), includes the step of procuring a table of joint statistics representing the probability of occurrence, in a frame of source data of each of the bits of the frame. The joint statistics may be determined ahead of time. The method includes the step of calculating intermediate gamma signals in response to the decoded data of the preceding frame and the joint statistics. The joint statistics source distribution signals represent the likelihood that, for a given logic level of the preceding bit, the “current” bit takes on a particular state; for uncorrelated bits, this value is 0.5. State probability signals and transition probability signals are generated from the gamma signals. The state probability and transition probability signals are processed to produce bit probability signals indicative of the probability that the current bit is in a given state, from which hard bit decisions can be made.
摘要:
The present techniques provide systems and methods for modulation coding of data on optical disks, such as holographic data disks, and techniques for reading that data back from the disks. The techniques involve parsing a bit stream into a sequence of individual bit-patterns, and then using the individual bit patterns to select a symbol, or matrix, from a lookup table of previously selected matrices. The symbols are selected according to predetermined criteria that may help make the disk more resistant to interferences and errors, such as surface scratches, and the like. For example, criteria that may be used to select the symbols are the number of reflective and non-reflective regions within each matrix, and the number of sequential reflective regions, among others. The symbols may be written to the disk in a two-dimensional fashion, e.g., across adjacent tracks, or in a three-dimensional fashion, e.g., across adjacent data layers.
摘要:
The present techniques provide methods and systems for reading and processing a data signal read from an optical data disc. In embodiments, an optical reader system may read data bits from a data ring in the disc. The data rings may be concentric, and a beginning of a sequence of data on the data ring may be in substantially the same position as an ending of the sequence. The reader may identify a data ring and begin the read process on the targeted data ring, and may end the read process when the reader reaches the starting point. The data sequence read from the data ring may be decoded to form a bit stream, which may be provided to various output devices. A circular trellis formed from the bit stream may enable the reading of a targeted data sequence without additional tail bits to improve data transmission efficiency.
摘要:
The present techniques provide systems and methods for modulation coding of data on optical disks, such as holographic data disks, and techniques for reading that data back from the disks. The techniques involve parsing a bit stream into a sequence of individual bit-patterns, and then using the individual bit patterns to select a symbol, or matrix, from a lookup table of previously selected matrices. The symbols are selected according to predetermined criteria that may help make the disk more resistant to interferences and errors, such as surface scratches, and the like. For example, criteria that may be used to select the symbols are the number of reflective and non-reflective regions within each matrix, and the number of sequential reflective regions, among others. The symbols may be written to the disk in a two-dimensional fashion, e.g., across adjacent tracks, or in a three-dimensional fashion, e.g., across adjacent data layers.