Which statement best describes the function of signal conditioning in sensor interfaces?

• A. It matches impedance, amplifies small signals, filters noise, scales to the ADC range, and improves accuracy.
• B. It converts digital outputs to analog for simple processing.
• C. It increases the size of the sensor.
• D. It eliminates the need for analog-to-digital conversion.

Answer: (A)

Signal conditioning prepares the sensor’s analog output for digitization by the ADC. It ensures the signal is clean, properly scaled, and can be accurately measured. This includes impedance matching so the sensor isn’t loading the circuit, amplifying small signals so they utilize most of the ADC’s dynamic range, filtering to remove noise and unwanted frequencies, and scaling or level-shifting to fit the ADC input range. Together these steps improve accuracy by reducing noise, distortion, and quantization error, and by making the signal compatible with the ADC’s requirements. The other statements don’t fit: converting digital outputs to analog is the reverse of what conditioning achieves; simply increasing the sensor’s size doesn’t address signal quality or compatibility with the ADC; and skipping the need for analog-to-digital conversion is not practical since digital processing requires a digitized signal.