Abstract: A device and method for canceling or attenuating harmonics noise without distorting the incoming signal. An exemplary device includes the use of an estimation loop to generate an artificial signal to eliminate or attenuate the influence of harmonics. The estimation loop includes a mixer adapted to produce a mixed signal by processing or combining the incoming signal and the artificial signal. The estimation loop includes an error detector, a low-pass filter, a parameter estimator, and a numerically controlled oscillator. The parameter estimator produces information relating to the phase, frequency, and amplitude of an incoming harmonics spur and will be used by the numerically controlled oscillator to generate the artificial signal. If the mixed signal contains relatively low levels of harmonics residuals, the mixed signal is produced at the output in lieu of the incoming signal.

Abstract: A system for providing multi-channel multi-mode QAM equalization and carrier recovery is provided. According to one exemplary embodiment, the system includes an equalization circuit and a carrier recovery circuit operating in a concurrent manner to provide equalization and carrier recovery. The equalization circuit and the carrier recovery circuit each have two operating modes, namely, an acquisition mode and a tracking mode. The carrier recovery circuit evaluates a phase detection error calculated based on signals obtained from the equalization circuit. Based on the evaluation of the phase detection error, the equalization circuit and the carrier recovery circuit are respectively directed to switch operating mode, if appropriate.

Abstract: A device and method for canceling or attenuating harmonics noise without distorting the incoming signal. An exemplary device includes the use of an estimation loop to generate an artificial signal to eliminate or attenuate the influence of harmonics. The estimation loop includes a mixer adapted to produce a mixed signal by processing or combining the incoming signal and the artificial signal. The estimation loop includes an error detector, a low-pass filter, a parameter estimator, and a numerically controlled oscillator. The parameter estimator produces information relating to the phase, frequency, and amplitude of an incoming harmonics spur and will be used by the numerically controlled oscillator to generate the artificial signal. If the mixed signal contains relatively low levels of harmonics residuals, the mixed signal is produced at the output in lieu of the incoming signal.

Abstract: A digital automatic gain control circuit is disclosed. The circuit includes a selector, a scaler, a detector, a gain adjustor and a controller. In one exemplary aspect, the selector receives an input signal having two components, namely, the in-phase (I) and quadrature (Q) components, in digital form. The selector then selects a subset of bits from each component based on a control signal provided by the controller. The two subsets are then forwarded to the scaler. The scaler then multiplies the two subsets respectively against a gain value to generate two multiplication results. A portion of each multiplication result is then provided as output by the scaler. The gain value and the subset selection are periodically adjusted in response to the scaler output. The adjustments with respect to the gain value and the subset selection are effectuated collectively by the detector, the gain adjustor and the controller.

Abstract: An improved multi-channel demodulator is provided. The improved demodulator includes an automatic gain control, a data buffer and a demodulation engine. Data from various RF channels are processed by the automatic gain control in order to keep the data at their respective constant levels. Output from the automatic gain control is passed to the data buffer for storage. Corresponding data from a selected channel is then processed by the demodulation engine. The improved demodulator is able to operate in any one of three operating modes, namely, a data processing mode, a channel switching mode and a waiting mode. In the data processing mode, the demodulation engine processes the channel data that is currently loaded into the demodulation engine. In the channel switching mode, the demodulation engine stores the current channel data into the data buffer and retrieves and loads channel data from another channel for processing.

Abstract: A method for determining a geographical location from a measured wireless signal signature comprises calculating from the measured wireless signal signature a multi-dimensional signature vector, wherein each component of the vector measures a degree of coincidence between the measured wireless signal signature and a calibrated signal signature stored in a calibration table. The method also includes matching the signature vector with vectors in a set of multi-dimensional calibrated vectors. The matching uses a procedure comprising searching a hierarchical tree structure and eliminating nodes that cannot contain the best match vector. Within the remaining nodes, the search eliminates individual vectors that cannot be the best match vector, and selects one or more vectors in the set of multi-dimensional calibrated vectors, where the matched vectors correspond to calibrated geographical locations.