Processing architecture for a receiving system with improved directivity and signal to noise ratio
AssigneeApex/Eclipse Systems, Inc.
InventorHarry Smith
Life of this patent
Estimating the term…
Abstract
A receive system providing enhanced directivity in the form of a narrowed receive beam and a relatively small antenna with performance comparable to a much larger antenna at similar frequencies. Received signals are converted to digital values and stored in a manner which enables subsequent processing directed to improving the resolution of the received signals and to reduce the associated noise corresponding to the received data samples. The Signal-to-Noise ratio of the received data signals is improved as a result of processing techniques made possible by the configuration of the antenna and the digitally stored nature of the received data.
Claims16
A method for increasing the signal to noise ratio of a receive system, said method comprising the steps of:
- receiving receive signals from an antenna array, said antenna array comprising a plurality of elements;
- amplifying said receive signals to form amplified signal-plus-noise signals;
- creating in-phase and quadrature versions of said receive signals wherein said in-phase and quadrature versions are about ninety degrees out of phase with respect to each other;
- determining an average noise and an average signal of said amplified signal-plus-noise signals;
- forming separate matrices each associated with either said in-phase or said quadrature versions of said receive signal, said matrices digitally representing a plurality of values, said values consisting of said in-phase or quadrature versions of said receive signals received from each element and a deviation of said in-phase or quadrature versions of said receive signals from said average noise;
- and
- selecting an amplified signal-plus-noise signal with a minimum deviation from said average noise;
- and performing an iterative process on data contained in said matrices to determine an estimate of the magnitude and polarity of the noise portion of the signal plus noise for each trial.
A process for substantially improving the signal to noise ratio of a receive system, said process comprising the step of:
- iteratively converging on an estimate of a noise-only portion of received signals plus noise for both in-phase and quadrature components of said received signals plus noise by simultaneously obtaining said noise-only estimates from a net algebraic sum of a series of iterations which provides a close approximations to the magnitude of the noise for each trial, and of opposite polarity;
- reducing the actual noise of said received signals plus noise by subtracting said close approximations from said received signals plus noise.
An iterative method of improving the signal to noise ratio in a receive signal, the method comprising:
- sampling the receive signal for at least two successive samples having the same phase reference using an analog to digital converter, wherein a system clock controls the timing of the sampling;
- establishing an array of signal-plus-noise values derived from the two successive samples;
- algebraically adding predetermined successive digital values to the signal-plus-noise values of the array;
- and
- assigning the predetermined successive digital values added to the array elements as either signal values or noise values during different iterations of the method
- wherein the signal does not alter the noise and the noise does not alter the signal.
A method for maximizing the signal to noise ratio of a receive signal, the method comprising:
- sequentially subtracting each surrogate value of a predetermined series of values from one or more samples of the receive signal;
- determining which of the values of the series of values results in a minimum deviation when subtracted from the samples of the receive signal representing a complete cycle of the receive signal
- identifying an optimum value from among the different surrogate values.
A method comprising:
- sequentially combining each of a series of numerical values with one or more samples of a positive half-cycle of a receive signal, wherein the samples of the positive half-cycle of the receive signal include a random noise component value and a data component value;
- sequentially combining each of the series of numerical values with one or more samples of a negative half-cycle of the receive signal, wherein the samples of the negative half-cycle of the receive signal include a random noise component value and a data component value having substantially the same magnitude as a corresponding data component value in the positive half-cycle thereby achieving a match between the positive and negative half cycles.
Dependencies are inferred from the claim text.