With the advancements in Digital Signal Processing, real time signal processing and applications are increasing day by day. One of the foremost application of real time signal processing is realization of digital filter. Software filter results i high quality precision, flexibility and wide areas of application. Various uses of DSP are given in the first chapter describing the importance of DSP in various fields. For realization of software filter, high quality special filters are used. These processors have special features like fast calculations and data processing abilities. ADSP 21xx series is one of such processor manufactured by ANALOG DEVICES. The processor is interfaced with the raw signal and processed to give filtered output. Signal could be from body ( e.g. ECG ), radar or satellite etc.
Our experiment takes the ECG signal from the heart and the software is designed to eliminate noise from the signal. The software is designed as an FIR band pass filter with band pass ranging from 1 Hz. to 49 Hz. The input signal is fed to ADSP port with the help of a sensing circuit. The raw waveform is filtered by the ADSP processor according to the controlling co-efficient and given to the CRO. What we get on the CRO is a filtered version of PQRST complex wherein the various peaks can be detected or measured on the CRO in terms of voltage or time period. The output gives a pure distortion less waveform and all the components beyond the passband are eliminated. Thus we conclude that a digital filter is realized.