Say you build an ADC or a DAC (or a scope/spectrum analyser) that has the best performance in the world. With what exactly do you test it with?
- Build the best ADC. You'll get digital numbers that you can collect, then run them through an FFT on your computer. But how do you know if your source or your ADC is the weak link if you get disappointing numbers?
- Build the best DAC. As long as you've a better ADC, you can use the ADC to measure the DAC.
Am I thinking along the right lines?