  Simultaneous observations at four different frequencies viz. 313, 607, 1380
and 4850 MHz, for three pulsars, PSRs B0031-07, B0809+74 and B2319+60, are
reported in this paper. Identified null and burst pulses are highly concurrent
across more than decade of frequency. Small fraction of non-concurrent pulses
(less than or equal to 3%) are observed, most of which occur at the transition
instances. We report, with very high significance for the first time, full
broadband nature of the nulling phenomenon in these three pulsars. These
results suggest that nulling invokes changes on the global magnetospheric
scale.
