Digital filter is a system, which applies a mathematical operation to discrete time signal x[n] in order to diminish or increase the particular aspect of signal. In this
manuscript, infinite impulse response (IIR) digital Narrow Band Stop (NBS) filter is employed. In filter design, a band stop filter, also known as a band reject filter, is a filter that allows most frequencies unchanged but has a very low level in a particular range. A band-stop filter with a condensed stop- band is a notch filter or Narrow Band Stop (NBS) filter. This paper carries out the hardware implementation of the digital Notch (NBS) filter. We have used IIR direct form- II structures for implementation. Time-changing bandwidth notch filters have been implemented using IIR structures. Xilinx ISE Tool is used to implement the suggested design on an FPGA. This Notch filter is also validated using MATLAB for sampling frequency of 1000 samples/second with notch frequency of 300 Hz. Here the input test data is taken with three frequency component of 100, 300 and 700 Hz. The hardware and software (MATLAB) implemented results clearly stops the 300 Hz frequency component with improved timing.