System and method for improved detection of AM signals

An apparatus operable to detect an amplitude modulated (AM) signal, comprising:

• a receiver operable to receive a radio frequency (RF) signal containing the AM signal modulated about a carrier frequency (fc) ;
• and
• a processing circuit operably coupled to a first local oscillator having a frequency flo and a second local oscillator, wherein the processing circuit is operable to:
• downconvert the RF signal with a first local oscillator having a frequency flo;
• produce an in-phase (I) signal and a quadrature (Q) signal;
• determine a relationship between fc and flo from a phase difference between a downconverted carrier signal of the I-channel signal and the Q-channel signal;
• and
• mix the I-channel signal and the Q-channel signal with a second set of local oscillators having frequencies and phases determined by the downconverted carrier signal to output a demodulated AM signal.

A digital amplitude modulated (AM) signal detector comprising:

• a receiver operable to receive a radio frequency (RF) signal containing the AM signal modulated about a carrier frequency (fc);
• a frequency detector operable to detect fc within the RF signal;
• a first local oscillator having a frequency flo;
• a second set of local oscillators;
• a processing circuit operably coupled to the first local oscillator, wherein the processing circuit is operable to:
• downconvert the RF signal with a first local oscillator having a frequency flo;
• and
• produce an in-phase (I) signal and a quadrature (Q) signal;
• a phase detector operable to determine a phase difference between the I-channel signal and the Q-channel signal;
• and
• a set of mixers operable to multiply the I-channel signal and the Q-channel signal with an output of the second set of local oscillators, wherein the frequencies and phases of the second local oscillator set are determined by the downconverted carrier signal of the downconverted RF signal and produce a demodulated AM signal.