Self-Programmable Multipurpose Digital Filter Design Based on FPGA

Conventional digital filter can only obtain fixed frequency domain characteristics at a time. In order to obtain variable characteristics, the digital filter´s type, number of taps and coefficients should be changed constantly such that the desired frequency-domain characteristics can be obtained. This paper proposes a method for self-programmable Variable Digital Filter (VDF) design based on FPGA. Taking finite impulse response (FIR) digital filter as an example, we implement a digital filter system by using Custom embedded Micro-Processor, programmable FIR macro module, coefficient-loader, clock manager and A/D or D/A controller and other modules. The self-programmable VDF can provide the best solution for realization of digital filter algorithms, which are the low-pass, high-pass, band-pass and band-stop filter algorithms with variable frequency domain characteristics. The design examples with minimum 1 to maximum 32 taps FIR filter, based on Modelsim post-routed simulation and onboard running on XUPV5-LX110T, are provided to demonstrate the effectiveness of the proposed method and the online-adaptability of variable digital filters.