Faults applied during March 1993 commissioning tests for the California-Oregon Transmission Project produced 14 Hz transient oscillations that were conspicuous in BPA's enhanced transducers at Malin, and in PG&E's Dynamic System Monitor at Table Mountain. Prony analysis of high speed fault data provided a detailed model for the underlying network resonance signal, and a basis for validating transient performance of a Macrodyne Phasor Measurement Unit (PMU) at the test site. This instrument, which is closely associated with EPRI's FACTS project, provides useful insight into emerging technology for high speed digital transducers. The phasor calculations are found to be of very high quality, but filtering enhancements are recommended for broadband applications.