Our high-time-resolution observations reveal that individual main pulses from the Crab pulsar contain one or more short-lived microbursts. Both the energy and duration of bursts measured above 1 GHz can vary dramatically in less than a millisecond. T
hese fluctuations are too rapid to be caused by propagation through turbulence in the Crab Nebula or the interstellar medium; they must be intrinsic to the radio emission process in the pulsar. The mean duration of a burst varies with frequency as $ u^{-2}$, significantly different from the broadening caused by interstellar scattering. We compare the properties of the bursts to some simple models of microstructure in the radio emission region.
We present Arecibo time-aligned, total intensity profiles for 46 pulsars over an unusually wide range of radio frequencies and multi-frequency, polarization-angle density diagrams and/or polarization profiles for 58 pulsars pulsars at some or all of
the frequencies 50, 111/130, 430 and 1400 MHz. The frequency-dependent dispersion delay has been removed In order to align the profiles for study of their spectral evolution and wherever possible the profiles of each pulsar are displayed on the same longitude scale. Most of the pulsars within Arecibos declination range that are sufficiently bright for such spectral or single pulse analysis are included in this survey--and the calibrated pulse sequences are available by web download for further study.
