  The generated relic gravitational waves were underwent several stages of
evolution of the universe such as inflation and reheating. These stages were
affected on the shape of spectrum of the waves. As well known, at the end of
inflation, the scalar field $\phi$ oscillates quickly around some point where
potential $V(\phi)=\lambda \phi^{n}$ has a minimum. The end of inflation stage
played a crucial role on the further evolution stages of the universe because
particles were created and collisions of the created particles were responsible
for reheating the universe. There is a general range for the frequency of the
spectrum $ \sim (0.3\times10^{-18}-0.6\times10^{10}$)Hz. It is shown that the
reheating temperature can be affect on the frequency of the spectrum as well.
There is constraint on the temperature from cosmological observations based on
WMAP-9 and Planck. Therefore it is interesting to estimate allowed value of
frequencies of the spectrum based on general range of reheating temperature
like few MeV $\lesssim T_{rh}\lesssim10^{16}$ GeV, WMAP-9 and Planck data then
compare the spectrum with sensitivity of future detectors such as LISA, BBO and
ultimate-DECIGIO. The obtained results of this comparison give us some more
chance for detection of the relic gravitational waves.
