The buzz cycle of a supersonic axisymmetric relaxed external compression inlet has been investigated in the 8'x6' supersonic wind tunnel at NASA Glenn Research Center. This inlet entails a mechanically simple design for providing a high-recovery/low-distortion flowfield and low sonic boom signature. Inlet buzz occurred at low mass-flow ratios with various vortex-generator configurations and Mach number values, providing an abundance of buzz data. High-speed schlieren and pressure measurements were used to characterize the inlet buzz. Schlieren movies not only allowed the characterization of the buzz cycle but also permitted the shock position to be tracked in time so that the frequency of the shock motion could be evaluated. The analysis revealed a dominant low frequency oscillation at 21.0 Hz corresponding with the duration of one buzz cycle. High-frequency shock position oscillations (spike buzz) were also observed throughout portions of the inlet buzz cycle.