A method of sampling a frequency difference in an integrated circuit is disclosed. The method comprises the steps of receiving a clock signal in a first clock domain; comparing a count of the clock signal in the first clock domain to a predetermined value N; converting the result of the comparison to a second clock domain; and generating an error signal representing the difference between the count of the first clock signal and the count of a second clock signal in the second clock domain. A circuit for sampling a frequency difference in an integrated circuit is also disclosed.