Measurement of rough surface scattering using time delay spectrometry

This paper describes a measurement approach for rough surface characterization, based on reflection mode Time Delay Spectrometry (TDS). The advantage of TDS is improved SNR and low peak power, relative to conventional pulse-echo methods. Because of simultaneous transmission and reception, the TDS system requires two transducers. The TDS measurement system is designed around a spectrum analyzer as the central analog signal processing unit. Due to insonification of a limited area of the rough surface, the mean of several independent measurements is required to reliably characterize the scattering behavior of a given rough surface. Backscatter data are obtained for a series of planar rough surfaces, in the form of scattering magnitude vs. frequency and incident (=backscatter) angle. Both focused and unfocused transducers in the lower MHz range have been used.