Method and apparatus to provide frequency translation of audio signal via switching and/or dc restoration

An apparatus to process a signal for providing a single sideband signal comprising:

• a modulating signal coupled to an input terminal of a predistortion circuit;
• coupling an output signal from the predistortion circuit to an input terminal of an In Phase processor;
• an output terminal of the In Phase processor provides a predistortion modulating In Phase signal;
• coupling the output signal from the predistortion circuit to an input terminal of a Quadrature Phase processor;
• an output terminal of the Quadrature Phase processor provides a predistortion modulating Quadrature signal;
• the predistortion modulating In Phase signal is coupled to a modulating input terminal of a first pulsewidth modulator;
• the first pulsewidth modulator includes a first phase carrier signal;
• the first pulse modulator provides a first pulsewidth modulated output signal;
• the predistortion modulating Quadrature Phase signal is coupled to a modulating input terminal of a second pulsewidth modulator;
• the second pulsewidth modulator includes a second phase carrier signal;
• the second pulsewidth modulator provides a second pulsewidth modulated output signal;
• the first pulsewidth modulated output signal is combined with the second pulsewidth modulated output signal to provide a first linearized single sideband signal;
• the predistortion circuit includes a third pulsewidth modulator, a nonlinear waveform, and a filter;
• the predistortion circuit linearizes the first pulsewidth modulator for providing a first linearized amplitude modulated signal;
• the predistortion circuit linearizes the second pulsewidth modulator for providing a second linearized amplitude modulated signal;
• the predistortion circuit provides the first linearized single sideband signal.

A method to provide multiple single sideband signals comprising:

• an input signal signal coupled to an input terminal of a predistortion system;
• the predistortion system including an output terminal providing multiple In Phase modulation signals and multiple Quadrature Phase modulation signals to a processor including multiple pulsewidth modulators;
• providing multiple In Phase carrier signals and multiple Quadrature Phase carrier signals to the processor including multiple pulsewidth modulators;
• the processor providing at least four pulsewidth modulated signals wherein each of the at least four pulsewidth modulated signals include at least four phases to provide at least a sequence of four pulse width modulated signals;
• combining at four pulsewidth modulated signals to provide a single sideband signal at a fundamental frequency and a single sideband signal of an opposite sideband at a harmonic of the fundamental frequency.