Apparatus and method for reducing phase noise in near field communication device signaling

An apparatus for reducing phase noise in near field communication (NFC) device signaling, the apparatus comprising:

• means for generating a transmission signal, an in-phase local oscillator signal, and a quadrature local oscillator signal from edges of an input clock signal;
• means for mixing a load modulated signal with the in-phase local oscillator signal to generate an in-phase baseband signal;
• means for mixing the load modulated signal with the quadrature local oscillator signal to generate a quadrature baseband signal;
• and
• means for adjusting a phase delay of at least one of the in-phase local oscillator signal or the quadrature local oscillator signal in response to a first signal strength of the in-phase baseband signal and a second signal strength of the quadrature baseband signal.

An apparatus for reducing phase noise in near field communication (NFC) device signaling, the apparatus comprising:

• an NFC initiator device including:
• a ring oscillator;
• a clock generator coupled to the ring oscillator, wherein a transmission signal generated by the clock generator is based on a clock signal that is generated by the ring oscillator;
• a first mixer responsive to an in-phase local oscillator signal and to a load modulated signal that is generated based on NFC signaling with an NFC target device;
• and
• a second mixer responsive to a quadrature local oscillator signal and to the load modulated signal;
• wherein an in-phase baseband signal is generated at the first mixer based on the in-phase local oscillator signal and the load modulated signal;
• and
• wherein a quadrature baseband signal is generated at the second mixer based on the quadrature local oscillator signal and the load modulated signal.

A non-transitory computer-readable storage medium, the non-transitory computer-readable storage device including instructions for reducing phase noise in near field communication (NFC) device signaling that, when executed by a processor, cause the processor to:

• determine a first signal strength of an in-phase baseband signal generated at an NFC initiator device, wherein the in-phase baseband signal is generated by mixing a load modulated signal with an in-phase local oscillator signal;
• determine a second signal strength of a quadrature baseband signal generated at the NFC initiator device, wherein the quadrature baseband signal is generated by mixing the load modulated signal with a quadrature local oscillator signal;
• and
• adjust a phase delay of at least one of the in-phase local oscillator signal or the quadrature local oscillator signal in response to the first signal strength and the second signal strength.