  In this paper, a novel instrument-based time-domain THz channel sounder for
the 300 GHz band is introduced. The performance is characterized by conducted
measurements and verified by over-the-air measurements, which confirm the
sensitivity and highlight the temporal resolution of the setup. Dynamic range,
maximum measurable path loss and phase stability are evaluated. The results
show that the performance in terms of dynamic range and maximum measurable path
loss is, to the best knowledge of the authors, unprecedented in this frequency
range.
