We present characterization of a lock-in amplifier based on a field programmable gate array capable of demodulation at up to 50 MHz. The system exhibits 90 nV/sqrt(Hz) of input noise at an optimum demodulation frequency of 500 kHz.The passband has a full-width half-maximum of 2.6 kHz for modulation frequencies above 100 kHz. Our code is opensource and operates on a commercially available platform.
@article{arxiv.1811.10494,
title = {An open-source high-frequency lock-in amplifier},
author = {G. A. Stimpson and M. S. Skilbeck and R. L. Patel and B. L. Green and G. W. Morley},
journal= {arXiv preprint arXiv:1811.10494},
year = {2019}
}