[en] Impact testing using digital Fourier analyser, by virtue of the fast Fourier transform is one of the recent and very fast methods of performing dynamic tests on structures. This method neither requires any elaborate fixing to hold the structure under test nor any electro-mechanical exciter. A hand-held hammer with a load cell mounted to it is uded to impact the structure. The load cell measures the input force and an accelerometer mounted on the structure measures the response. Two CIRP test-rigs, with intended single degree of freedom systems, used for co-operative chatter research have been tested by impact testing. A digital H.P. Fourier analyser has been used to analyse the input and the response signals in time/frequency domain and to print out the transfer function values. From the transfer function values the compliance curves and the characteristics of the test-rigs have been derived. (Author)