A number of application examples are provided with the PIC18FXXK20 Demonstration Board. One of these applications uses a Discrete Fourier Transform (DFT) to highlight the performance characteristics of the new PIC18FXXK20 MCU. As shown in the figure, this application uses a microphone connected to the audio input on the demonstration board. This signal then passes through a Low-Pass filter to the 10-bit ADC. The digitized samples are then transformed to the frequency domain using a DFT and displayed as a 16-point spectral representation on the board’s display.