Patent ID: 7010014

Claim:
A method for spreading the electromagnetic emissions of a generated clock signal that is created in response to a reference clock signal, the method comprising the steps of: providing the reference clock signal to an adjustable delay line having a plurality of selectable delay trim units; generating a first control signal for enabling a first set of the delay trim units in the adjustable delay line, the first set being selected to provide the generated clock signal having a base clock period; generating a second control signal for adjusting the first set of delay trim units, the second control signal being selected to vary in a predetermined pattern; combining the first control signal and the second control signal to create a third control signal; and providing the third control signal to the adjustable delay line, wherein the third control signal causes different sets of the delay trim units to be enabled during different cycles of the reference clock signal, thereby causing the generated clock signal to exhibit a repeating regular pattern of varying clock periods, wherein the pattern of the varying clock periods includes the base clock period, as well as clock periods greater than and less than the base clock period.