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

We have developed a digital lock-in (DLI) technique with improved signal-to-noise characteristics for magnetotransport experiments in pulsed magnetic fields. The basic idea of the DLI is to digitize both the high-frequency sample signal and the reference during the entire high field shot and to evaluate the data sets afterwards with respect to the principles of the phase sensitive detection by appropriate software. Sophisticated 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.