How does the PC noise affect the measurement on my plug-in data acquisition board?

How does the PC noise affect the measurement on my plug-in data acquisition board?

Noise is always an important issue to deal with, whether the measurement hardware is a standalone instrument or a plug-in data acquisition board. The noise generated by the PC is not unique to the PC itself. Most components in the PC do exist in a standalone instrument as well, such as clocks, multiplexers, switching power supplies, and various digital circuits. It is the task of the analog designer to predict the sources of noise and minimize their effects, like adding low pass filters or isolating the digital circuit from the analog circuit or conditioning the power coming into the board or even shielding. RF noise is everywhere and it could affect the measurement device inside or outside the PC. The noise in the measurement associated with PC boards is less a result of PC noise and more a result of the fact that traditional standalone instruments use integrating A/D technology, while plug-in data acquisition boards use successive approximation A/Ds that are more susceptible to noise.