System and method for generating a multi-component signal including a modulated signal and an auxiliary signal

A method, comprising:

• receiving a multi-component analog signal including a modulated signal and an auxiliary zero-crossing modulated signal encoding input digital data;
• generating digital samples of the modulated signal;
• mixing the digital samples of the modulated signal with a carrier signal for the modulated signal to create a downconverted signal;
• and
• decoding the downconverted signal to obtain estimates of the input digital data.

An apparatus, comprising:

• an input port receiving input digital data;
• an auxiliary signal generator configured to generate, based upon the input digital data, zero-crossing modulated waveform data encoding the input digital data wherein the zero-crossing modulated waveform data represents an auxiliary zero-crossing modulated waveform having a plurality of periods wherein portions of the plurality of periods are perturbed in at least one of amplitude and phase relative to a sinusoid;
• and
• a mixer connected to the auxiliary signal generator, the mixer being configured to mix the zero-crossing modulated waveform data and modulation data representing a modulated signal so as to produce a multi-component signal.