Accuracy in a data acquisition is a very important thing. An analog signal to be analyzed need to be converted into digital numbers. Unfortunately the number of bits of the representator number limit the accuracy of the representation. More number means more accuracy, but the cost to do so is skyrocketing. Therefore in this study, tests were done on oversampling and dithering method to increase the accuracy of the digital representation without the need of additional hardware cost. The study is done using 10 bit ADC in Atmega8 with LM35 thermal sensor as the input. These components assembled together to form a data acqusition module with USB connection to PC. The dither signal generator in this module generates a triangle wave to emulate gaussian data distribution that happens when white noise is present in the input signal, this distribution is required by the oversampling process. The module can save result data into a file that can be used for further analysis. The result shows that dithering is required to do oversampling on a 10 bit ADC, with frequency required to lie between oversampling result frequency and ADC sampling frequency. Increase in accuracy as big as 62,9 times of the original was achieved for additional 6 digital bit with 4096 times of data sampling which required 0.8 second (1,2Hz) to finish.

Kata Kunci : oversampling, dithering, data acquisition, accuracy