Method for adding random noise in a time-to-digital converter circuit and circuits for implementing the method

摘要

The method involves processing a rapid signal (F-DCO) by delay chains (41-1-41-n), and generating a thermometric code. PN bits of the code are reduced from the code. The reduced bits are processed to generate variables representing difference of rise and fall times of the signal with respect to a slow reference signal (Fref). Gain is calculated to generate average value of frequency of the reference signal. A binary value corresponding to number of bits is added to one variable. The added value is multiplied with the average value, and a phase difference between the signals is calculated. Independent claims are also included for the following: (1) a time to digital converter comprising a set of flip-flops (2) a frequency synthesis circuit for generating high frequency signal.