2012-03-052012-03-052006-06-06http://hdl.handle.net/11007/484We derive first and second order general slow-roll inverse formulae giving the Hubble parameter H in terms of the gravitational wave spectrum. We also derive improved forward general slow-roll formulae giving the gravitational wave spectrum in terms of the Hubble parameter H. Moreover, the general slow-roll consistency condition relating the scalar and tensor spectra is obtained.enGravitational waveSpectrumHubbleArticle