Transmitter apparatus and methods using frequency doubling modulation

A transmitter circuit, comprising:

• a phase modulating oscillator circuit operative to generate an oscillator signal that has a first frequency and that is phase modulated responsive to a phase modulation signal;
• a frequency doubler circuit configured to receive the phase-modulated signal and operative to produce an output signal therefrom that has a second frequency;
• and
• a power amplifier circuit responsive to the output signal produced by the frequency doubler circuit and operative to generate an amplified output signal therefrom.

A transmitter circuit, comprising:

• an oscillator circuit operative to generate first and second differential pairs of oscillator signals in quadrature relationship to one another;
• a modulator circuit configured to receive the first and second oscillator signals and a modulation signal, the modulator circuit comprising:
• first and second cross-coupled differential amplifier circuits that control first and second currents passing from first and second nodes to respective third and fourth nodes responsive to a differential pair of modulation signals;
• and
• third and fourth differential amplifier circuits coupled to respective ones of the third and fourth nodes of the first and second differential amplifier circuits and operative to control current flow therebetween responsive to respective ones of the first and second differential pairs of oscillator signals;
• and
• a power amplifier circuit responsive to the output signal produced by the modulator circuit and operative to generate an amplified output signal therefrom.

A transmitter circuit, comprising:

• an oscillator circuit operative to generate an oscillator signal;
• means, operatively associated with the oscillator circuit, for producing a frequency-doubled phase-modulated output signal from the oscillator signal, the frequency-doubled phase-modulated output signal phase modulated according to a modulation signal;
• and
• a power amplifier responsive to the frequency-doubled phase-modulated output signal and operative to generate an amplified output signal therefrom.

A method of operating a transmitter, comprising:

• generating an oscillator signal having a first frequency;
• producing a frequency-doubled modulated output signal from the oscillator signal, the frequency-doubled modulated output signal phase modulated according to a modulation signal and having a second frequency that is about twice the first frequency;
• amplifying the frequency-doubled modulated output signal;
• and
• transmitting the amplified frequency-doubled modulated output signal in a communications medium.