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DY: Fachverband Dynamik und Statistische Physik

DY 39: Data Analysis and Stochastic Modeling II (jointly with UP)

DY 39.3: Vortrag

Donnerstag, 17. März 2011, 17:30–17:45, ZEU 255

How to measure low frequency signals with a sound card — •Thomas John and Dirk Pietschmann — Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg

Modern sound cards as analog/digital-converter are cheap because of monolithic circuit design. They have a spectacular signal to noise ratio of more than 100 dB. A common disadvantage in usage as measurement instrument in laboratories is the low-pass filtering, with prevents exact measurements for frequencies below 100 Hz. We present a software based algorithm to bypass this disadvantage. All tested sound cards could be characterized by only two parameters for frequency behavior and one parameter for relative voltage scaling. These parameters can be easily determined with our algorithm. The achieved accuracy is approx 5 µV to 1 V in a frequency range from below 1 Hz up to 24 kHz with exact phase determination of the applied signal.