Abstract: A technique for spectral widening in a communication system may divide respective symbols of a block of symbols into symbol pieces of shorter duration than a symbol. The symbol pieces may be scrambled. The resulting scrambled symbol pieces may optionally be further spread using direct-sequence spreading prior to transmission. Error-control coding may also be used prior to dividing the symbols into symbol pieces and scrambling the symbol pieces. Additionally, the number of symbol pieces per symbol may be adjustable, based on channel characteristics, performance, or both.

Abstract: Techniques for compensating for frequency offset of a frequency used in a translation of a signal from a first band to a second band may include using a frequency reference signal located in a different band from an information-bearing signal, where the different band may be a guard band. The frequency reference signal may be offset from a particular frequency, which may be a center frequency, of the information-bearing signal by a known amount. The frequency reference signal may be received by the transmitting station, a frequency offset may be derived, and the frequency offset may be used to pre-compensate further transmitted signals. At another station, the received frequency reference signal may be used to lock a local oscillator for demodulation and/or transmission of the information-bearing signal based on the known offset of the frequency reference signal from the frequency of the information-bearing signal.

Abstract: Techniques for compensating for frequency offset of a frequency used in a translation of a signal from a first band to a second band may include using a frequency reference signal located in a different band from an information-bearing signal, where the different band may be a guard band. The frequency reference signal may be offset from a particular frequency, which may be a center frequency, of the information-bearing signal by a known amount. The frequency reference signal may be received by the transmitting station, a frequency offset may be derived, and the frequency offset may be used to pre-compensate further transmitted signals. At another station, the received frequency reference signal may be used to lock a local oscillator for demodulation and/or transmission of the information-bearing signal based on the known offset of the frequency reference signal from the frequency of the information-bearing signal.

Abstract: Techniques for compensating for frequency offset of a frequency used in a translation of a signal from a first band to a second band may include using a frequency reference signal located in a different band from an information-bearing signal, where the different band may be a guard band. The frequency reference signal may be offset from a particular frequency, which may be a center frequency, of the information-bearing signal by a known amount. The frequency reference signal may be received by the transmitting station, a frequency offset may be derived, and the frequency offset may be used to pre-compensate further transmitted signals. At another station, the received frequency reference signal may be used to lock a local oscillator for demodulation and/or transmission of the information-bearing signal based on the known offset of the frequency reference signal from the frequency of the information-bearing signal.

Abstract: A technique for spectral widening in a communication system may divide respective symbols of a block of symbols into symbol pieces of shorter duration than a symbol. The symbol pieces may be scrambled. The resulting scrambled symbol pieces may optionally be further spread using direct-sequence spreading prior to transmission. Error-control coding may also be used prior to dividing the symbols into symbol pieces and scrambling the symbol pieces. Additionally, the number of symbol pieces per symbol may be adjustable, based on channel characteristics, performance, or both.

Abstract: A technique for spectral widening in a communication system may divide respective symbols of a block of symbols into symbol pieces of shorter duration than a symbol. The symbol pieces may be scrambled. The resulting scrambled symbol pieces may optionally be further spread using direct-sequence spreading prior to transmission. Error-control coding may also be used prior to dividing the symbols into symbol pieces and scrambling the symbol pieces. Additionally, the number of symbol pieces per symbol may be adjustable, based on channel characteristics, performance, or both.

Abstract: A technique for spectral widening in a communication system may divide respective symbols of a block of symbols into symbol pieces of shorter duration than a symbol. The symbol pieces may be scrambled. The resulting scrambled symbol pieces may optionally be further spread using direct-sequence spreading prior to transmission. Error-control coding may also be used prior to dividing the symbols into symbol pieces and scrambling the symbol pieces. Additionally, the number of symbol pieces per symbol may be adjustable, based on channel characteristics, performance, or both.

Abstract: A transmitter transmits a signal to a receiver using spread spectrum signals. The transmitter generates a respective signal. The transmitter separates the respective signal into multiple predefined portions, wherein each predefined portion is below a noise floor. The transmitter transmits at least a plurality of the predefined portions of the respective signal at discrete bandwidth intervals in accordance with a spread spectrum signal splitting technique. The discrete bandwidth intervals are portions of spectrum that are available for transmission. The receiver receives at least a plurality of the multiple predefined portions of the respective signal at the discrete bandwidth intervals. The receiver reconstructs the respective signal using at least a plurality of the predefined portions in accordance with the spread spectrum signal splitting technique.

Abstract: Several systems and methods for locating blood vessels are described in the present disclosure. One of the implementations of a blood vessel locating system comprises an image capture device and processing circuitry. The image capture device is configured to capture a first image of a region of the skin of a subject when the region is illuminated by a first light and to capture a second image of the region of the skin when the region is illuminated by a second light. The processing circuitry is configured to calculate the difference between the first image and the second image to obtain a differential image. The processing circuitry is further configured to enhance the differential image to obtain an enhanced image of blood vessels located under the surface of the skin of the subject.

Abstract: Several systems and methods for locating blood vessels are described in the present disclosure. One of the implementations of a blood vessel locating system comprises an image capture device and processing circuitry. The image capture device is configured to capture a first image of a region of the skin of a subject when the region is illuminated by a first light and to capture a second image of the region of the skin when the region is illuminated by a second light. The processing circuitry is configured to calculate the difference between the first image and the second image to obtain a differential image. The processing circuitry is further configured to enhance the differential image to obtain an enhanced image of blood vessels located under the surface of the skin of the subject.

Abstract: A receiving system allows for the coherent detection of a spread-spectrum transmission at any point in time during the transmission, thereby avoiding the need to identify the start of the transmission during the transmission-detection process. An input buffer captures the transmissions on a communication channel using a moving time-window. A detector processes a time-slice from the input buffer and identifies all of the simultaneously transmitting transmitters during that time-slice. As each transmitter is identified, the demodulator traces back-in-time to identify where the message can first be detected in the input buffer. The transmission includes suitable characteristics to facilitate detection and demodulation of the message content, but need not contain a preamble to allow the detection process.

Abstract: A receiving system dynamically searches a communications band for transmissions of messages having the same nominal communications parameters, including the use of the same spreading code, but having potentially different specific frequencies and code-phases. The receiver samples the communications band at each code-phase of the spreading code over a span of down-converted transmission frequencies. When a message element is detected at a particular code-phase and frequency, it is forwarded to a demodulator that demodulates the message and sends it to its intended destination. This technique allows each transmitter to be independent of the receiver. In a preferred embodiment of this invention, a Fast M-Sequence Transform (a Walsh-Hadamard Transform) is used to determine the power level at multiple code-phases at a given frequency in parallel, thereby substantially reducing the time required to search for transmissions at each discrete code-phase.

Abstract: A spacecraft architecture and accompanying standard allows for the creation of a spacecraft using an assortment of modules that comply with the standard. The standard preferably includes both mechanical and electrical compatibility criteria. To assure physical/mechanical compatibility, the structure of each module is constrained to be compatible with any other compatible module. To minimize the interference among modules, the extent of each module in select dimensions is also constrained. To assure functional compatibility, a common communication format is used to interface with each module, and each public-function module is configured to respond to requests for function capabilities that it can provide to other functions. Each module is preferably designed to provide structural support to the assemblage of modules, and an anchor module is provided or defined for supporting the entire assemblage and coupling the assemblage to other structures, such as a launch vehicle.

Abstract: A network architecture and protocol provides “plug and play” spacecraft capabilities. A distributed-control architecture is used, wherein each component operates semi-autonomously, and interacts with other components on a task/resource level. Each component announces its requirement for system resources as a request to the network, and components that can provide some or all of the requested resources respond to the request. An arbitration device centralizes and coordinates requests for critical and/or singular resources, such as requests for a specific orientation of the spacecraft. To facilitate such distributed control, requests are made in advance of the requirement for the resource, and include a time interval during which the resource is required. A configuration and test system is provided to process the mission requirements and provide a set of components that can be configured to satisfy the requirements.

Abstract: A communication system is provided that allows the use of low-cost, low-power remote terminal units that communicate substantially asynchronously and independently to a base station. To minimize cost and complexity, the remote terminal units are configured similarly, including the use of substantially identical transmission schemes, such as a common Direct Sequence Spread Spectrum (DSSS) code. To minimize collisions among transmissions, the communication system is designed to use a high-gain antenna with a limited field of view, to limit the number of cotemporaneous, or overlapping transmissions that are received at the base station. To cover a wide area, the limited field of view is swept across the area of coverage. To overcome potential losses caused by collisions, the remote terminal units are configured to repeat transmissions; to minimize repeated collisions, the repeat interval and/or duration is randomized.

Abstract: Disclosed herein are position determining apparatus and conductor structures or grids therefor. The conductor structure for each axis includes a number of conductors which are run in a serpentine-type path each with uniform repeat increment. The repeat increment, which is the spacing or span between one run and the next of the same serpentine-type conductor, are uniform for each conductor (but may change from conductor to conductor) and is constrained by a maximum repeat increment, or a minimum repeat increment. In the preferred embodiments, there is at least a constraint on the maximum repeat increment to provide noise immunity. The conductors are arranged for each axis of the grid in a pattern such that signals obtained for that axis may be processed to provide binary numbers in a Gray-type code each unique to a small region of the active area in which the coil center is located.