Methods and apparatus for reducing high-frequency events in polar domain signals

A method of reducing high-frequency events in a polar domain signal, comprising:

• generating an unmodified rectangular-coordinate signal, with a modulator, having in-phase (I) and quadrature phase (Q) components modulated according to a predetermined modulation scheme;
• detecting, with a high-frequency detection and reduction unit configured to detect a first sample of the signal having in phase (I) and quadrature phase (Q) components;
• modifying the first sample of said unmodified rectangular-coordinate signal based on how close said first sample is to the origin in a complex signal plane and how fast a signal trajectory between said first sample and a subsequent sample changes, to produce a modified rectangular-coordinate signal by calculating a magnitude of a trajectory vector defining said signal trajectory between said first sample and a subsequent sample and modifying said first sample based on a magnitude of said first sample and a magnitude of said trajectory vector,
• wherein modifying said first sample comprises determining a pushing vector for pushing said first sample away from the origin in the complex signal plane and scaling said pushing vector depending on the magnitude of said first sample and the magnitude of said trajectory vector by defining a symbol interval around said first sample, said symbol interval including a leading sample that is N/2 time units earlier than said first sample and a lagging sample that is N/2 units later than said first sample, where N represents an oversampling rate of samples of the I and Q signals over a symbol rate;
• scaling said pushing vector based on positions of the leading and lagging samples among signal constellation points in a signal constellation representative of said predetermined modulation scheme;
• and
• converting said modified rectangular-coordinate signal to a polar domain signal having amplitude and phase components,
• wherein by modifying said first sample, either or both the amplitude and phase components of said polar domain signal have reduced high-frequency content compared to a polar domain signal that would be generated without said first sample having been first modified.