2001ApJ...546..394J

The single-pulse characteristics of the millisecond pulsar PSR B1937+21 are studied using the recently installed Caltech baseband recorder at the Arecibo Radio Observatory in Puerto Rico. This is the first such analysis of this object that includes both average intensity pulses as well as ``giant pulses.'' Pulse ensemble-averaging techniques are developed in order to study the characteristics of PSR B1937+21's single pulses since the high time resolution signal-to-noise ratio is less than unity. This analysis reveals that the non-giant pulse radio emission is extremely stable. All observed fluctuations are consistent with diffractive interstellar scattering. Such intrinsic stability has yet to be observed in other radio pulsars.