US Patent 9264219 Clock and data recovery circuit and method

A clock and data recovery (CDR) circuit and method are disclosed herein. The CDR circuit includes a data analysis module, a loop filter module and a phase adjust module. The data analysis module generates an error signal according to an input data, a first clock signal, and a second clock signal. The loop filter module generates a first corrective signal according to the error signal, a frequency threshold value, and a phase threshold value. The phase adjust module generates the first clock signal and the second clock signal according to the first corrective signal. The loop filter module further accumulates the error signal to generate an accumulated value, and to compare the accumulated value with an accumulated threshold value, so as to dynamically adjust the accumulated threshold value, the frequency threshold value, and the phase threshold value.