RF carrier synchronization and phase alignment methods and systems
A method comprising generating a baseband information signal by mixing a received modulated carrier signal with a local oscillator (LO) signal having an LO frequency; obtaining baseband signal samples of the baseband information signal having a baseband signal magnitude and a baseband signal phase; determining a cumulative phase measurement associated with baseband signal samples having a baseband signal magnitude greater than a threshold; and, applying a correction signal to compensate for an LO frequency offset of the LO frequency based on the cumulative phase.
1. A method comprising:
generating a baseband information signal by mixing a received modulated carrier signal with a local oscillator (LO) signal having an LO frequency;
obtaining baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample;
determining an offset frequency rotation based on an estimated correlation between the in-phase signal samples and the quadrature signal samples;
processing the baseband information signal using the offset frequency rotation;
determining an offset phase associated with the estimated correlation between the in-phase signal samples and the quadrature signal samples;
processing the baseband information signal using the offset phase; and
determining the offset phase based on a symmetry property of the estimated correlation, the symmetry property being measured with respect to a plurality of frequency offsets.
2. A method comprising
generating a baseband information signal by mixing a received modulated carrier signal with a local oscillator (LO) signal having an LO frequency;
obtaining baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample;
determining an offset frequency rotation based on an estimated correlation between the in-phase signal samples and the quadrature signal samples;
processing the baseband information signal using the offset frequency rotation;
determining an offset phase associated with the estimated correlation between the in-phase signal samples and the quadrature signal samples;
processing the baseband information signal using the offset phase; and
determining the offset frequency rotation and offset phase with respect to a maximum value of the estimated correlation, wherein the estimated correlation is calculated using a plurality of candidate phase offsets over a first range and candidate frequency rotations over a second range.
3. The method of claim 2 further comprising updating the offset frequency rotation and the offset phase by recalculating a maximum value of the estimated correlation, wherein at least one of the first range and the second range is reduced.