Spread Spectrum Clock Generator

The invention discloses a spread spectrum clock (SSC) generator used for generating an SSC signal. The SSC generator is provided with a first reversible counter working at a fixed first duration time (t1), a first PRBS generator working at a variable second duration time (t2), a second reversible counter working at a fixed third duration time (t3) and a second PRBS generator working at a variable fourth duration time (t4). A state machine sequentially triggers the first counter and the first PRBS generator to generate a positive portion of a period of the SSC signal, and then sequentially triggers the second counter and the second PRBS generator to generate a negative portion of the period of the SSC signal. For a set of parameters stored in a configurable register, the first duration time and the third duration time are fixed from period to period, but the second duration time and the fourth duration time vary from period to period.