INTERPOLATION OF MICROCONTROLLER ADC BY SELF- INDUCED DITHERING

摘要

The resolution of ADCs (Analog-to-Digital Converters) can be improved by dithering, i.e. byintentionally injecting white noise into the analog signal. This work describes the theory behinddithering, how to optimize the magnitude of the noise and also a design that illustrates how ditheringcan be implemented to increase the resolution of a microcontroller’s ADC. In order to demonstrate thepotential of the design, the resolution of the 10-bit ADC of a PIC18F458 microcontroller is increased to12 bits by dithering. This is possible by oversampling and decimation. The great advantage of theproposed design is that the noise is generated by the microcontroller itself, obviating the need of anexternal noise source.