Data acquisition of noise or interference corrupted measurement signals

Data acquisition (DAQ) with a personal computer equipped with a DAQ board is often corrupted by interference and noise. This is very harmful particularly if the changes to be measured are small compared with the interference coming from the electrical network. However, this noise can be used as a dither signal to improve the resolution of the A/D converter as well as to decrease the uncertainty of noisy measurements. A classical uniform dithering may be also combined with the noise or interference. This paper presents the general framework of dithering, theoretical improvement available with various types of dithering signals, and a virtual instrument for designing the application. A universal dithering is also presented giving a possibility to become insensitive to the changes in the interference amplitude.