Self-calibrating modulator apparatuses and methods

A method of countering nonlinearities of a controlled oscillator, comprising:

• configuring a controlled oscillator in a closed-loop frequency control circuit of a modulator apparatus;
• tuning and locking said frequency control circuit to cause an output frequency of said controlled oscillator to be centered at a center frequency;
• opening a loop of the frequency control circuit;
• applying a test pattern signal to a control input of said controlled oscillator, said test pattern signal representing a plurality of reference frequencies that cause the output frequency of the controlled oscillator to deviate from said center frequency;
• measuring a plurality of output frequencies of the controlled oscillator for each reference frequency represented in the test pattern signal;
• and
• calculating a plurality of oscillator gain coefficients from said plurality of measured output frequencies.

A polar modulation transmitter, comprising:

• an amplitude modulation path having an amplitude modulator configured to amplitude modulate a direct current power supply signal according to amplitude variations in an amplitude modulation signal received in the amplitude modulation path;
• a phase modulation path including a self-calibrating modulator apparatus having a phase modulator having a direct modulation path, a feed-forward path, and a controlled oscillator having a control input configured to receive signals from the direct modulation path and the feed-forward path and an oscillator gain calibration circuit coupled to the feed-forward path of said phase modulator, said self-calibrating modulator apparatus operable to calculate frequency dependent oscillator gain coefficients for use by said phase modulator to counter nonlinear frequency responses of said controlled oscillator;
• and
• a power amplifier configured to amplify a phase modulated carrier signal generated by said phase modulator according to an amplitude modulated power supply signal applied to a power setting input of said power amplifier from said amplitude modulator,
• wherein said direct modulation path and said feed-forward path receive a modulation signal.