Wind tunnel experiments up to Mach 3 have provided fluctuating wall-pressure spectra beneath a supersonic turbulent boundary layer to frequencies reaching 400 kHz by combining data from two types of fast-response pressure sensors. Data were corrected for spatial attenuation at high frequencies and for wind-tunnel noise and vibration at low frequencies. A comparison of the pressure fluctuation intensities with fifty years of historical data shows their reported magnitude chiefly is a function of the frequency response of the sensors. The present corrected data yield results in excess of the bulk of the historical data, but uncorrected data are consistent with lower magnitudes, suggesting that much of the historical compressible database may be biased low. The resulting power spectra are used to assess theories for the behavior of boundary layer pressure fluctuations in different frequency ranges. Additional data acquired from a spanwise array of pressure sensors reveal signatures of coherent structures that resemble similar structures known to exist in the velocity field, which provide an explanation for the physical origin of fluctuations at frequencies well below those associated with the boundary layer thickness.

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