  The stochastic gravitational wave background (SGWB) detected recently by the
pulsar timing arrays (PTAs) observations may have cosmological origins. In this
work we consider a model of single field inflation containing an intermediate
phase of ultra slow-roll. Fixing the amplitude of the peak of curvature
perturbations by the PBHs bounds we calculate the gravitational waves (GWs)
induced from the curvature perturbations enhanced during USR. The spectrum of
the induced GWs depends on the sharpness of the transition from the USR phase
to the final attractor phase as well as to the duration of the USR period.
While the model can accommodate the current PTAs data but it has non-trivial
predictions for the induced GWs on higher frequency ranges which can be tested
by future observations.
