Altiostar Networks, Inc.

John N Ibison

Data is received characterizing a first signal and a second signal. The first signal and a function of the second signal is compared at a plurality of time-shifts to estimate a time-difference between the first signal and the second signal. The function of the second signal includes the second signal, a complex conjugate of the second signal, and a constant. The comparison is provided. At least one of receiving, comparing, and providing is performed by at least one processor of at least one computing system.

Time-alignment of signals suffering from quadrature errors

In one aspect a computer-implemented method is performed. The method may include capturing intermediate data samples for transmission by a wireless communications transmitter. The method may further include applying signal processing to the intermediate data samples, capturing output data samples after applying the signal processing, and/or determining quadrature correction coefficients from the intermediate data samples and the output data samples, wherein the quadrature correction coefficients remove quadrature errors caused by the signal processing. The method may further include applying the quadrature correction coefficients to a series of input data samples, wherein the intermediate data samples comprise the input data samples with the quadrature correction coefficients applied to the input data samples. The capturing the intermediate data samples, the applying the signal processing, the capturing the output data samples, the determining the quadrature correction coefficients, and the applying the quadrature correction coefficients may be performed by at least one processor.

Correction of quadrature modulation errors

A method is presented which performs crest factor reduction (CFR) on a digitized signal. The method may include determining one or more peak values in a series of data samples of a communication signal, and/or generating a peak queue comprising the one or more peak values that exceed a threshold value and a corresponding index values for each peak value. The method may further include generating, from the peak queue, an entry to a clip table, the entry including a clip coefficient at the corresponding index value, updating the clip table to include a new clip coefficient at a new corresponding index value when the clip function squared at the new index value exceeds a scaled output power for an input power at the new corresponding index value, and/or clipping the series of data samples in a neighborhood of the peak value according to the clip function.

Crest factor reduction

Data characterizing a first signal and a second signal can be received. A first stream of bits for the first signal and a second stream of bits for the second signal can be calculated based on the received data. Each bit in the first stream of bits can characterize a slope of a power of the first signal and each bit in the second stream of bits can characterize a slope of a power of the second signal. The first stream of bits and the second stream of bits can be compared bitwise at a plurality of time-alignment differences for matching bits. Based on the comparing a final time-alignment difference between the first signal and the second signal can be determined. At least one of the receiving, the calculating, the comparing, and the determining can be performed by at least one processor of at least one computing system.

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Bradford, United Kingdom

John N Ibison