Time to digital converter with increased range and sensitivity

An apparatus comprising:

• an analog receiver circuit configured to receive a modulated signal having a carrier frequency;
• a phase-to-digital conversion (PDC) circuit coupled to the analog receiver circuit and configured to obtain a phase measurement between the modulated signal and a local clock signal;
• a carrier-based phase correction circuit coupled to the PDC circuit and configured to generate a carrier-based phase correction value by accumulating a phase-correction increment;
• a corrected phase measurement circuit coupled to the carrier-based phase correction circuit and configured to generate a corrected phase measurement value based on a difference between the phase measurement and the carrier-based phase correction value;
• and
• a carrier phase measurement circuit coupled to the corrected phase measurement circuit and configured to generate a carrier phase measurement by scaling the corrected phase measurement value.

A method comprising:

• obtaining a plurality of phase measurements of a local clock associated with signal transitions of a carrier having a carrier frequency and a phase-modulation component;
• generating an adjusted local clock phase measurement by subtracting an offset based on a frequency difference between the carrier frequency and a frequency of the local clock;
• and
• generating a phase modulation value by scaling the adjusted local clock phase measurement based on a ratio between the carrier frequency and the frequency of the local clock.