An Analog-to-Digital converter (ADC) is a device that converts an Analog signal to its Digital equivalent. The ADC is the bridge between the analog and digital in the world of SDR. It is in fact a key component of SDR.
The output of an ADC is a string of ones and zeros that vary with the incoming signal. This string can be processed by a Field Programmable Gate Array (FPGA) or a microprocessor.
Here are two examples of processing that can occur in the FPGA:
- A Fast Fourier Transform (FFT) to convert the time domain signal to its frequency domain equivalent.
- Digital filtering and demodulation to extract the content in the analog waveform.
The simplest way to get hands-on with an ADC is to get yourself an Arduino. The Arduino has a total of six analog input header pins that connect to its ADC.
Here are a couple of resources to get you started with understanding how to use the ADC in an Arduino.