A multi-frequency amplitude modulator for encoding electrical signals in MR images
Hanson L, Hanson C
Copenhagen University Hospital Hvidovre
Using rudimentary hardware, it has previously been demonstrated that electrophysiological signals can be modulated and encoded in a way similar to the ""mag stripe"" technique used for representation of sound tracks in movies: The signals are encoded in the oversampled region of the field-of-view discarded by the image reconstruction. Non-MR signals can thereby be recorded by the scanner without affecting the images. A much improved flexible modular 8-channel modulator was constructed for the purpose. Filters, gains, trigger timings and frequencies are controlled via an optical PC-link. The equipment provides easy high-quality recording of non-MR signals.