In my latest work on Analog Circuits and Filter Design, I’ve had the opportunity to explore a fascinating project that brings theory into practice—an ECG signal processing experiment. Take a moment to watch the video.
This project is a key component of our current learning kit for Analog Signals and Filter Design, where I share systematic explanations, design insights, and hands-on experiments that demystify the world of analog circuitry. In this article, I’ll walk through the design principles, module functionalities, and practical setup of this experiment, highlighting how it can serve both as an educational tool and as a robust demo for real-world applications.
Project OverviewElectrocardiography (ECG) is a prime example of where precise analog signal processing is essential. Capturing the tiny electrical signals generated by the heart and processing them to extract meaningful data involves both linear circuit design and effective filtering techniques.
One of the core principles behind this project is modularity. Each of the four modules is designed as a standalone PCB, allowing you to mix, rearrange, and customize the setup based on your specific learning or teaching requirements. This modular approach not only enhances the reliability of the system but also makes troubleshooting and incremental improvements much simpler.
This project is built around four essential modules, each designed as a compact PCB for reliability and modularity:
- Instrumentation AmplifierThis module is responsible for capturing and amplifying the minute differential signals from the heart. Its high input impedance and excellent common-mode rejection are critical for accurate signal acquisition in biomedical context
- High-Pass FilterTo ensure that the essential features of the ECG waveform are preserved, the high-pass filter eliminates low-frequency noise and DC offsets, which can be introduced by patient movement or even breathing. This step is vital to maintain the fidelity of the signal.
- Notch FilterOne of the common challenges in ECG signal processing is the interference from power line noise (50/60Hz). The notch filter is specifically designed to suppress this interference, ensuring that the ECG signal is not compromised by ambient electromagnetic disturbances.
- Low-Pass FilterFinally, the low-pass filter is used to mitigate high-frequency noise, such as EMI and harmonic distortions. This helps in cleaning up the signal further, making the waveform ready for analysis and diagnostic purposes.
- Flexibility: Adapt the system for various experiments by reconfiguring or upgrading individual modules.
- Ease of Use: The plug-and-play nature of the PCBs allows beginners and professionals alike to build and test the system on a breadboard.
- Scalability: Whether you're conducting classroom demonstrations or detailed research, the modular design can be scaled to meet your needs.
For those who enjoy a hands-on approach, building this project on a breadboard is both a challenging and rewarding experience. Here’s a quick rundown of the build process:
- Setup the PCBs: Start by placing the four compact PCBs (Instrumentation Amplifier, High-Pass Filter, Notch Filter, and Low-Pass Filter) on your breadboard. Their standardized form factor simplifies integration.
- Interconnect the Modules: Connect the modules sequentially—first capturing the ECG signal, then filtering out unwanted frequencies in stages. Each module’s output feeds directly into the next stage, ensuring a clean signal path.
- Lab-On-The-Go Integration: For an enhanced learning experience, I recommend testing your build using a Lab-On-The-Go setup. This portable platform allows you to observe real-time signal processing, making it an excellent demo for classroom or workshop environments.
- Calibration and Testing: Use professional benchtop instruments for calibration to verify the performance of your setup. While the breadboard demo is great for initial testing, benchtop instruments can provide a higher level of precision when needed.
This ECG signal processing experiment is not only a fantastic educational tool for exploring analog circuit design but also a practical demonstration of how sophisticated signal processing can be achieved with a modular, scalable system. Embedded within my upcoming learning kit, this project comes with comprehensive circuit explanations, detailed design notes, and all the essential hardware to get you started.
Whether you are an educator, a student, or a hobbyist looking to delve into the realms of biomedical instrumentation and analog filtering, this project offers a rich, hands-on experience that bridges theory and practice. I invite you to explore, build, and experiment with this system—each step brings you closer to mastering the art of analog signal conditioning.
Happy building!
If you're interested in a comprehensive learning experience, our complete kit includes a well-illustrated book and all the necessary components and hardware — everything you need to dive into analog signals and filter design. Consider supporting us at this link.
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