The invention relates to a high-speed serial interface circuit, and discloses a
linearity calibration and precision expansion method of a
numerical control phase interpolator. According to the method, a digital
delay converter (DDC) is cascaded behind a
digital control phase interpolator (DPI), and
delay compensation is carried out on an interpolated
clock signal; sampling the compensated
clock signal by using an analog-to-
digital converter (ADC) to obtain a phase sampling value; the calibration control module calculates a
phase error and generates a
delay control word; when the
numerical control phase interpolator DPI works,
phase control words and delay control words are synchronously provided for corresponding modules, and
linearity calibration and precision expansion are achieved. According to the method, a special detection circuit does not need to be added, hardware resources existing in a high-speed serial interface are utilized, the method can be achieved through simple
digital control logic, the phase integral
linearity is improved to be within 25 fs from 250 fs, meanwhile, the precision of an 8-bit phase interpolator is improved to be close to the 11-bit level, and the method is suitable for large-scale popularization and application. And the
clock recovery performance and the
data transmission reliability of the high-speed communication
system are obviously improved.