  We describe a pulsed multi-frequency electron paramagnetic resonance
spectrometer operating at several frequencies in the range of 110-336 GHz. The
microwave source at all frequencies consists of a multiplier chain starting
from a solid state synthesizer in the 12-15 GHz range. A fast PIN-switch at the
base frequency creates the pulses. At all frequencies a Fabry-Perot resonator
is employed and the pi/2 pulse length ranges from ~100 ns at 110 GHz to ~600 ns
at 334 GHz. Measurements of a single crystal containing dilute Mn2+ impurities
at 12 T illustrate the effects of large electron spin polarizations. The
capabilities also allow for pulsed electron nuclear double resonance
experiments as demonstrated by Mims ENDOR of 39K nuclei in Cr:K3NbO8.
