A circuit includes a time-to-digital converter (TDC) to produce an output signal that is a function of a time difference between a first input clock to the TDC and a second input clock to the TDC. A first delay line is also included to add a time delay to a third clock to produce the first input clock. A pseudo random binary sequence generator generates a pseudo random binary bit sequence to be used to vary the amount of time delay added by the first delay line to the third clock.