Figure: Filtered signal of real-time ECG data and it's spectrum response.
Abstract: This project focused on designing, analyzing, and implementing digital filters to remove noise from Electrocardiogram (ECG) signals and improve the clarity of cardiac waveform interpretation. Using MATLAB 2019a, I worked with both Infinite Impulse Response (IIR) and Finite Impulse Response (FIR) filters to evaluate their effectiveness in eliminating unwanted frequency components. Various filter types—including low-pass, high-pass, band-pass, and band-stop—were examined, with the notch (band-stop) filter identified as the most suitable for suppressing specific noise frequencies commonly found in ECG data.
Throughout the project, I defined filter specifications, designed appropriate filter structures, calculated the required parameters, and analyzed performance using frequency and phase spectrum visualizations. When unwanted frequency components were still present, I refined and tuned the filter design accordingly. Finally, I evaluated the stability and efficiency of each designed filter.
The project outcomes showed that IIR filters offered efficient filtering with low latency but required careful stability considerations, whereas FIR filters provided stable, linear-phase responses with higher computational demand.
References:
Learnings:
Gained hands-on experience in implementing different types of digital filters for effective signal filtration.
Improved understanding of IIR and FIR filter behavior, performance, and stability considerations.
Strengthened skills in analyzing frequency and phase spectra using MATLAB.
Learned to tune and optimize filter parameters to achieve improved noise removal in ECG signals.
Difficulties Faced:
Faced difficulty in selecting the appropriate type of digital filter and its corresponding window for effective ECG signal filtering.
Required multiple iterations and parameter tuning to achieve the desired noise reduction without distorting the original ECG waveform.
My role in this project: This was a solo project in which each student was assigned a different problem based on their student ID. I was fully responsible for the design, analysis, and implementation of the digital filters used for ECG signal noise reduction. All tasks—including defining filter specifications, writing MATLAB code, calculating filter parameters, visualizing results, and evaluating performance—were completed independently by me.
