Physical layer circuit, clock recovery circuit and calibration method of frequency offset

A physical layer circuit comprising:

• an equalizer, for equalizing a digital received signal generated by sampling based on a sampling clock signal, and generating an equalized sampling signal;
• and
• a clock recovery circuit, comprising:
• a phase detector, for receiving the equalized sampling signal to calculate a plurality of phase differences in a plurality of time windows;
• a loop filter electrically connected to the phase detector, for correspondingly generating a plurality of loop pulses in the time windows according to the phase differences;
• a free wheel circuit, for generating a plurality of free wheel is pulses;
• an output circuit electrically connected to the loop filter and the free wheel circuit, for receiving the loop pulses and the free wheel pulses, and generating a plurality of phase-shifting pulses correspondingly;
• and
• a controller electrically connected to the free wheel circuit and the output circuit, for calculating a first accumulative correction offset according to the phase-shifting pulses generated by the output circuit in a previous time window of the time windows,
• wherein the free wheel circuit periodically generates the free wheel pulses during a current time window of the time windows according to the first accumulative correction offset, the current time window being next to the previous time window,
• wherein the sampling clock signal is adjusted according to the phase-shifting pulses generated by the output circuit.

A calibration method of frequency offset applied to a physical layer circuit of a receiver, the calibration method of frequency offset comprising steps of:

• equalizing a digital received signal generated by sampling based on a sampling clock signal to generate an equalized sampling signal;
• calculating a plurality of phase differences in a plurality of time windows according to the equalized sampling signal;
• generating a plurality of loop pulses correspondingly in the time windows according to the phase differences;
• periodically generating a plurality of free wheel pulses during a current time window of the time windows according to a first accumulative correction offset:
• generating a plurality of phase-shifting pulses correspondingly according to the loop pulses and the free wheel pulses;
• and
• adjusting the sampling clock signal according to the phase-shifti g pulses,
• wherein the first accumulative correction offset is calculated according to the phase-shifting pulses generated in a previous time window prior to the current time window.