Carrier supression in a nfc receiver

A receiver comprising:

• first and second input terminals for receiving first and second input signals;
• a digital-to-analog converter (DAC) for providing a current;
• a mixer having a first input coupled to receive the first and second input signals and a second input coupled to receive the current from the DAC, and in response, the mixer provides a combined current;
• a track-and-hold circuit having an input coupled to receive the combined current and an output to provide a series of output samples;
• an amplifier coupled to receive the output signal from the track-and-hold circuit and to provide an amplified output signal;
• and
• an analog-to-digital converter (ADC) coupled to receive the amplified output signal and to provide a digital representation of the amplified output signal.

A near-field communication (RFC) receiver comprising:

• first and second input terminals for receiving first and second input signals, respectively, wherein the first and second input signals include a modulated portion and a carrier portion;
• a first channel comprising:
• a first digital-to-analog converter (DAC) to provide a first current;
• a first mixer circuit having a first input coupled to receive the first and second input signals and a second input coupled to receive the first current, and in response, the first mixer circuit provides a first combined signal, wherein the carrier portion is at least partially suppressed in the combined signal;
• a first track-and-hold circuit having an input coupled to receive the first combined signal, and an output to provide a first series of track-and-hold output samples;
• a first amplifier coupled to receive the first track-and-hold output samples, and an output to provide a first amplified output signal;
• and
• a first analog-to-digital converter (ADC) coupled to receive the first amplified output signal, and an output to provide a digital representation of the first amplified output signal;
• and
• a second channel comprising:
• a second DAC to provide a second current;
• a second mixer circuit having a first input coupled to receive the first and second input signals, and a second input coupled to receive the second current, and in response, the second mixer circuit provides a second combined current, wherein the carrier portion is at least partially suppressed in the combined signal;
• a second track-and-hold circuit having an input coupled to receive the second combined current, and an output to provide a second track-and-hold output signal;
• a second amplifier coupled to receive the second track-and-hold output signal, and an output to provide a second amplified output signal;
• and
• a second analog-to-digital converter (ADC) coupled to receive the second amplified output signal, and an output coupled to provide a digital representation of the second amplified output signal.

A near-field communication (RFC) receiver comprising:

• first and second input terminals for receiving first and second input signals, respectively, wherein the first and second input signals includes a modulated portion and a carrier portion;
• a first quadrature channel comprising:
• a first digital-to-analog converter (DAC) to provide a first current;
• a first mixer circuit having a first input coupled to receive the first and second input signals and a second input coupled to receive the first current, and in response, the first mixer circuit provides a first combined current, wherein the carrier portion of the first and second input signals is at least partially suppressed in the combined current;
• a first track-and-hold circuit having an input coupled to receive the first combined signal, and an output to provide a first series of track-and-hold output samples;
• a first averaging circuit having an input coupled to the output of the first track-and-hold circuit to receive the first series of track-and-hold output samples, and an output for providing an output signal that is an average of two consecutive output samples of the first series of track-and-hold output samples;
• a first amplifier coupled to receive the output signal from the first averaging circuit, and an output to provide a first amplified output signal;
• and
• a first analog-to-digital converter (ADC) coupled to receive the first amplified output signal, and an output to provide a digital representation of the first amplified output signal;
• and
• a second quadrature channel comprising:
• a second DAC to provide a second current;
• a second mixer circuit having a first input coupled to receive the first and second input signals, and a second input coupled to receive the second current, and in response, the second mixer circuit provides a second combined current, wherein the carrier portion of the first and second input signals is at least partially suppressed in the second combined current;
• a second track-and-hold circuit having an input coupled to receive the second combined current, and an output to provide a second series of track-and-hold output samples;
• a second averaging circuit having an input coupled to the output of the second track-and-hold circuit to receive the second series of track-and-hold output samples, and an output to provide an output signal that is an average of two consecutive output samples of the second series of track-and-hold output samples;
• a second amplifier coupled to receive the output signal from the second averaging circuit, and an output to provide a second amplified output signal;
• and
• a second analog-to-digital converter (ADC) coupled to receive the second amplified output signal, and an output coupled to provide a digital representation of the second amplified output signal.