Lena/Aug 2016: Difference between revisions

The magnetometer can take the vector measurements in two channels: X and Y. The Y is orthogonal to both pump and probe, and provides the sensitivity to the main direction at DC, while the X direction signal is demodulated at 1kHz. An LabVIEW filter in FPGA is setup to separate the two signals. The Y signal is obtained by low-pass filtering the signal with two 2-order Butterworth filters, while the X signal is obtained by multiplying the time signal by a reference and low-pass filtering it by the same filters.

 

The problem is that the Y channel often has large digitization noise (see the picture). The digitization noise disappears when one of the Butterworth filters is deleted (but then the filtering is insufficient).