A DIGITAL LOCK-IN-TECHNIQUE FOR PULSED MAGNETIC-FIELD EXPERIMENTS

We have developed a digital lock-in (DLI) technique with improved sign al-to-noise characteristics for magnetotransport experiments in pulsed magnetic fields. The basic idea of the DLI is to digitize both the hi gh-frequency sample signal and the reference during the entire high fi eld shot and to evaluate the data sets afterwards with respect to the principles of the phase sensitive detection by appropriate software. S ophisticated noise elimination procedures, such as FFT filtering, can easily be implemented. Each DLI channel is able to detect the in-phase and the quadrature signal simultaneously. We demonstrate the superior properties of our DLI system by comparing actual measurement results with those taken with the well-established analog lock-in technique.