1994A&A...286..807S

We have investigated the statistics of signals obtained with high time resolution at 1400 MHz and at 102.5 MHz from the pulsar PSR 1133+16 at pulse longitudes corresponding to both components of the average pulse profile. Observations were not simultaneous at both frequencies. We have determined the probability for the presence of microstructure and for the presence of quasi-periodicities for the two observing frequencies. Probability of microstructure appearance has been determined to be the cause of decrease of the average microstructure component at high frequencies. We show that the distribution of characteristic times of microstructure is substantially different for pulse components I and II of the average pulse profile at 1400 MHz, although the probability for the presence of microstructure and for the presence of quasi-periodicities is independent of the longitude of the pulse component. The average characteristic time of microstructure is the same at both pulse component longitudes at both frequencies. The observations are interpreted in terms of pulsar emission models.