The ____ is responsible for converting analog ECG signals to digital data.

• A. Data acquisition system
• B. Signal amplifier
• C. Analog-to-digital converter
• D. Digital signal processor

Answer: (B)

Converting analog ECG signals to digital data is done by the analog-to-digital converter. The ECG signal is continuous in time and amplitude, and before digitization it’s typically amplified and conditioned to improve fidelity. The amplifier increases the signal strength, but it doesn’t change it into digital form. The ADC then samples the conditioned analog waveform at discrete time intervals and quantizes each sample into a digital value, producing the data that a computer or processor can work with. After digitization, a digital signal processor can filter, analyze, and interpret the data. The data acquisition system encompasses the whole front-end, including sensors, conditioning, and conversion, but the actual conversion from analog to digital occurs specifically in the analog-to-digital converter.