  We examine the X-ray spectral and temporal behavior of the Galactic black
hole candidate source GRS 1915+105 during its spectral state transition
observed in 1997 March - August. The source was making a slow transition from a
low-hard state to a high-soft state in about three months and during this
transition it was exhibiting a series of fast variations which can be
classified as bursts. During one type of bursts, called the irregular bursts,
it was found that the source makes rapid transitions between two intensity
states. We have analyzed the RXTE PCA data obtained on 1997 June 18 (when the
source was making rapid state transitions) and compared the results with two
sets of data each pertaining to the low hard-state and high-soft states. We
find that the power density spectrum (PDS) during the burst shows remarkable
similarity to that seen during the high-soft state of the source. The PDS
during the quiescence, on the other hand, is quite flat and is very similar to
the PDS commonly seen during the canonical low-hard state of black hole X-ray
binaries. A low frequency QPO at $\sim$3 Hz is observed during the quiescence,
a property seen during the low-hard state of the source. The X-ray spectrum of
the source during quiescence is similar to the spectrum seen during the
low-hard state of the source and the spectra during the burst and high-soft
state are very similar to each other. These observations corroborate the
suggestion made by Yadav et al. (1999) that during the irregular bursts the
source shows spectral state variations at very fast time scales. We explain
such fast state changes using the two component accretion flow model in which
the accretion disk consists of a geometrically thin (and optically thick)
standard disk co-existing with an advection dominated hot thick disk.
