Performance evaluation of multirate filters for digital down converters

For achieving maximum signal transfer without any noise in all available communication systems, the frequency of the processor is synchronized with the sampling rate of the signal. The use of multirate filtering allows designers to achieve this. In this paper, the multirate filters with and without compensation have been implemented very effectively using FPGA (field programmable gate arrays). Also, comparison of FIR (finite impulse response) filters and differential delay farrow filters has been done for different sampling frequencies. The proposed filter structures have wide applications in the designing of sample rate converters, analog to digital converter, decimators and interpolators. It can be concluded from the design results that the proposed structures can be used efficiently in the designing of any communication system.   Key words: Multirate filters, compensation, DDC (digital down converter), WiMax (worldwide interoperability for microwave access), FPGA (field programmable gate arrays).