Patent ID: 7961040

Claim:
A mixed-signal chip having a first portion of analog circuitry and second portion of digital circuitry, the chip comprises: an on-chip precision oscillator residing on the first analog portion, the precision oscillator has a precision frequency; a first on-chip non-precision tunable oscillator from a first clock domain residing on the first analog portion, the first non-precision tunable oscillator has a first adjustable frequency; a noise detector for detecting a first noise in the first clock domain; a frequency adjusting register for storing a first desired frequency value of the first on-chip non-precision tunable oscillator, wherein the first desired frequency value is determined based on the first noise; a control circuit for adjusting the first adjustable frequency of the first non-precision tunable oscillator to the first desired frequency value by using the precision frequency of the on-chip precision oscillator as a reference; a second on-chip non-precision oscillator from a second clock domain residing on the first analog portion, the second non-precision oscillator having a second adjustable frequency, wherein the control circuit is further coupled to adjust the second adjustable frequency to a second desired frequency based on the precision frequency of the on-chip precision oscillator; and a second noise detector which detects a second noise in the second clock domain, wherein the second desired frequency is determined based on the second detected noise.