  We have revisited the problem of off-pulse emission in pulsars, where
detailed search for the presence of low level radio emission outside the pulse
window is carried out. The presence of off-pulse emission was earlier reported
in two long period pulsars, PSR B0525+21 and B2046-16 at frequencies below 1
GHz using the Giant Meterwave Radio Telescope (GMRT). However, subsequent
studies did not detect off-pulse emission from these pulsars at higher radio
frequencies (> 1 GHz). We have carefully inspected the analysis scheme used in
the earlier detections and found an anomaly with data editing routines used,
which resulted in leakage of signal from the on-pulse to the off-pulse region.
We show that the earlier detections from PSR B0525+21 and B2046-16 were a
result of this leakage. The above analysis scheme has been modified and
offline-gating has been used to search for off-pulse emission in 21 long period
pulsars (P > 1.2 sec) at different observing frequencies of GMRT. The presence
of low level off-pulse emission of peak flux 0.5 mJy was detected in the
brightest pulsar in this list PSR 0B0628-28, with off-pulse to average pulsar
flux ratio of 0.25%. We suggest that coherent radio emission resulting due to
cyclotron resonance near the light cylinder can be a possible source for the
off-pulse emission in this pulsar.
