Systems and methods for up-sampling a polar amplitude sample stream in a polar modulator

A polar modulator comprising:

• an input configured to receive an in-phase sample stream and a quadrature sample stream, wherein the in-phase sample stream and the quadrature sample stream together characterize a data signal in an IQ plane;
• a coordinate system converter configured to receive the in-phase sample stream and the quadrature sample stream from the input and to generate a polar amplitude sample stream and a polar phase sample stream;
• an up-sampler configured to receive the polar amplitude sample stream from the coordinate system converter and to generate an up-sampled polar amplitude sample stream, the up-sampler comprising:
• an origin-crossing identifier configured to analyze at least one of the polar amplitude sample stream or the polar phase sample stream and to responsively adjust an inversion trigger;
• a controlled inverter configured to selectively apply an inversion to the polar amplitude sample stream based on the inversion trigger to form a selectively inverted polar amplitude sample stream;
• an interpolator configured to receive the selectively inverted polar amplitude sample stream from the controlled inverter and to interpolate the selectively inverted polar amplitude sample stream to form an interpolated selectively inverted polar amplitude sample stream;
• and
• an inversion removal module configured to receive the interpolated selectively inverted polar amplitude sample stream from the interpolator and to remove the inversion to form the up-sampled polar amplitude sample stream;
• and,
• a carrier-signal modulator configured to receive the up-sampled polar amplitude sample stream and the polar phase sample stream and to modulate a carrier signal based on the up-sampled polar amplitude sample stream and the polar phase sample stream.

A polar modulator comprising:

• an input configured to receive an in-phase sample stream and a quadrature sample stream, wherein the in-phase sample stream and the quadrature sample stream together characterize a data signal in an IQ plane;
• a coordinate system converter configured to receive the in-phase sample stream and the quadrature sample stream from the input and to generate a polar amplitude sample stream and a polar phase sample stream;
• an up-sampler configured to receive the polar amplitude sample stream from the coordinate system converter and being further configured to:
• analyze at least one of the polar amplitude sample stream or the polar phase sample stream and responsively adjust an inversion trigger;
• selectively apply an inversion to the polar amplitude sample stream based on the inversion trigger to form a selectively inverted polar amplitude sample stream;
• interpolate the selectively inverted polar amplitude sample stream to form an interpolated selectively inverted polar amplitude sample stream;
• and
• remove the inversion from the interpolated selectively inverted polar amplitude sample stream to form an up-sampled polar amplitude sample stream;
• and,
• a carrier-signal modulator configured to receive the up-sampled polar amplitude sample stream from the up-sampler and the polar phase sample stream from the coordinate system converter and being further configured to modulate a carrier signal based on the up-sampled polar amplitude sample stream and the polar phase sample stream.