Embodiments of the present invention provide a clock signal generator, and the clock signal generator is applied to a physical layer subsystem supporting data transmission at multiple baud rates. The clock signal generator includes: a source clock signal generator, and two or more processors connected to an output end of the source clock signal generator; where the source clock signal generator outputs multiple source clock signals with the same frequency according to a reference signal of a reference clock in the subsystem; the processors perform frequency dividing processing on the multiple source clock signals through a digital logic circuit according to an oversampling technology, to obtain a synchronous clock signal corresponding to a baud rate of data transmission in the subsystem, so as to implement timing and transceiving functions when data is transmitted at the baud rate.