Achieving Higher ADC Resolution Using Oversampling
Jayanth Murthy Madapura
An Analog-to-Digital Converter (ADC) is an active interface between the analog and digital signal chains in an embedded system. An ADC converts analog signals into digital signals in electronic systems. The key feature of an ADC is the accuracy (resolution) it offers. The higher the desired accuracy, the higher the ADC cost.
Higher ADC accuracy is achieved by designing hardware to quantize the analog signal amplitude into the digital signal with a higher code-word length. Practical ADCs have finite word lengths.
To effectively strike a balance between system cost and accuracy, higher conversion accuracy is achieved by oversampling the low-resolution ADC integrated within a digital signal controller (DSC), and then processing the oversampled digital signal in software through a digital filter and a decimator. This processing scheme, which adds additional bits of accuracy to the 12-bit ADC conversion in a dsPIC® DSC, is explored in this application note.
ADC Resolution, Oversampling