Abstract: A cognitive HF radio is disclosed having a cognitive engine that optimizes HF transmission parameters on the basis of learned experience with previous transmission under varying transmission and environmental conditions. Additionally, electrically small HF antennas optionally using non-Foster matching elements are disclosed. Furthermore, another electrically small HF antenna and associated impedance matching networks are disclosed, including an impedance matching network using non-Foster matching elements.

Abstract: A cognitive HF radio is disclosed having a cognitive engine that optimizes HF transmission parameters on the basis of learned experience with previous transmission under varying transmission and environmental conditions. Additionally, electrically small HF antennas optionally using non-Foster matching elements are disclosed. Furthermore, another electrically small HF antenna and associated impedance matching networks are disclosed, including an impedance matching network using non-Foster matching elements.

Abstract: Multiuser classification of the modulation schemes of simultaneous multiple unknown transmitters is disclosed. Cooperation among multiple cognitive radio receivers for modulation classification offers improvements in classification performance and overcomes detrimental channel effects that degrade single cognitive radio classifier performance. A centralized soft-combining data fusion algorithm based on the joint probability distribution of fourth order cumulants is presented for cooperative modulation classification. Fourth order cumulants of received signals are calculated as discriminating features for different modulation schemes at each cognitive radio node and sent to a centralized data node. The data node chooses the modulation scheme that maximizes the joint probability of the estimated cumulants.

Abstract: An intelligent cognitive radio system is disclosed that acquires information about its environment to make operational decisions. Dynamic radio frequency mapping provides estimates of RF power levels over an area where spectrum activity or changes in the environment may be transient. These power levels can be used for a variety of applications such as interference management, spectrum policing, and facilitating spectrum auctions. The RF mapping can be accomplished by a network of sensors that are distributed in a geographical area and used to spatially sample signal levels. The present invention can quantify the effect of aliasing on the estimation of an RF map as a function of the sampling density and the number of antennas used at the sensing node.

Abstract: Multiuser classification of the modulation schemes of simultaneous multiple unknown transmitters is disclosed. Cooperation among multiple cognitive radio receivers for modulation classification offers improvements in classification performance and overcomes detrimental channel effects that degrade single cognitive radio classifier performance. A centralized soft-combining data fusion algorithm based on the joint probability distribution of fourth order cumulants is presented for cooperative modulation classification. Fourth order cumulants of received signals are calculated as discriminating features for different modulation schemes at each cognitive radio node and sent to a centralized data node. The data node chooses the modulation scheme that maximizes the joint probability of the estimated cumulants.

Abstract: A system and related methods for allowing for an increase in the use of spectrum resources through market based mechanisms for spectrum management. Spectrum trading mechanisms are implemented that allow for assignment and allocation decisions to be made by market forces. The system helps moderate an environment where buyers and sellers dynamically determine the assignment of spectrum and its uses.

Abstract: An example Cognitive Radio (CR) described herein may include equalization and Automatic Modulation Classification (AMC). The equalization may employ digital filter techniques with an adjustable length or order. The output of the equalization may be provided to the AMC, where the AMC may be adapted to identify various characteristics about the RF environment and also to identify probabilities of classification associated with the performance of the AMC itself. The CR device may be configured to adjust the equalization using feedback from the AMC to enhance performance of each other.

Abstract: Techniques for producing an output signal using an outphasing transmitter are disclosed. In some examples, constant modulation (CM) signals may be produced from a digital input signal. The CM signals may be converted to an analog state and filtered. The signals may then be modulated to produce modulated signals, which may be amplified. The amplified signals may be combined to produce combined signals, which may further be combined to produce an output signal.

Abstract: Techniques for producing an output signal using an outphasing transmitter are disclosed. In some examples, constant modulation (CM) signals may be produced from a digital input signal. The CM signals may be converted to an analog state and filtered. The signals may then be modulated to produce modulated signals, which may be amplified. The amplified signals may be combined to produce combined signals, which may further be combined to produce an output signal.

Abstract: An example Cognitive Radio (CR) described herein may include equalization and Automatic Modulation Classification (AMC). The equalization may employ digital filter techniques with an adjustable length or order. The output of the equalization may be provided to the AMC, where the AMC may be adapted to identify various characteristics about the RF environment and also to identify probabilities of classification associated with the performance of the AMC itself. The CR device may be configured to adjust the equalization using feedback from the AMC to enhance performance of each other.

Abstract: A multiplierless IIR filter incorporates power-of-two coefficients to perform shift operations to reduce space and increase speed. To optimize performance, a genetic algorithm generates the power-of-two coefficients. The filter architecture includes shift registers to receive input samples and previous outputs. A shifter stage is employed to perform shift operations for the input samples and previous outputs based on corresponding power-of-two coefficients. Products are added by parallelism and sequential pipelining to produce an output.

Abstract: A multiplierless IIR filter incorporates power-of-two coefficients to perform shift operations to reduce space and increase speed. To optimize performance, a genetic algorithm generates the power-of-two coefficients. The filter architecture includes shift registers to receive input samples and previous outputs. A shifter stage is employed to perform shift operations for the input samples and previous outputs based on corresponding power-of-two coefficients. Products are added by parallelism and sequential pipelining to produce an output.

Abstract: A method for determining pressure in an operating Coriolis effect mass flowmeter. The Coriolis flowmeter flow tubes are vibrated in both a bending mode (as is normal for measuring mass flow rate) and in a twisting mode. The ratio of the fundamental frequencies at which the flow tubes vibrate in each of the two vibration modes is proportional to the pressure within the flow tubes. In the preferred embodiment, a sum/difference method initially isolates the superposed sinusoids representing the fundamental frequencies of the two vibrational modes. Fast conjugate gradient (FCG) digital filters are then used to rapidly estimate the fundamental frequencies in each of the two vibration modes. The estimated frequencies are then used by filter chains including digital notch and band pass filters as well as recursive maximum likelihood (RML) digital filter techniques to enhance the bending mode and twisting mode fundamental frequency estimates.

Abstract: An apparatus and method for determining frequency and phase relationships of vibrating flow tubes in a Coriolis mass flow meter. Adaptive line enhancement (ALE) techniques and apparatus are used in a digital signal processing (DSP) device to accurately determine frequency and phase relationships of the vibrating flow tube and to thereby more accurately determine mass flow rate of a material flowing through the mass flow meter. In a first embodiment, an adaptive notch filter is used to enhance the signal from each corresponding sensor signal on the vibrating flow tubes. In a second embodiment, a plurality of adaptive notch filters are cascaded to enhance the signal from each corresponding sensor signal. In both embodiments an anti-aliasing decimation filter associated with each sensor signal reduces the computational complexity by reducing the number of samples from a fixed frequency A/D sampling device associated with each sensor signal.