DIGITAL FILTER WITH SAMPLING RATE REGULATION FUNCTION

A digital filter capable of changing the sampling rate is provided to set the sampling rate of the arbitrary fractional ratio at the time-varying system by changing the up-sampling rate of the interpolator and the down-sampling rate of the attenuator. A digital filter capable of changing the sampling rate includes a synthesizer, an up-sampler, an integrator, a down-sampler and a direct digital synthesizer(30). The synthesizer synthesizes the input signal. The up-sampler performs the up-sampling for the input synthesized signal. The integrator integrates the signal up-sampled through the up-sampler. The down sampler performs the down-sampling for the integrated up-sampling signal. And, the direct digital synthesizer(30) controls the up-sampling value of the up-sampler and the down-sampling value of the down sampler in response to the selection of the user.