This paper presents typical and worst case root mean square (rms) delay spreads, excess delay spreads (10 dB) and mean channel path loss at 900 MHz in four European cities using typical cellular and microcellular antenna locations. A power law propagation model is used to determine how the mean wide-band channel path loss changes as a function of distance between a base and a mobile. It is shown that a change in reference distance from 1 km to 100 m can change the perceived propagation power law exponent from 3.0 to 2.7, where free space propagation is assumed from the transmitter to the reference distance. The data reveal that for microcellular sites with low base antennas, rms delay spreads are less than 2 ps with excess delay spreads (10 dB) less than 6 ps. When high base station antennas are used, rms delay spreads are generally less than 8 ps and excess delay spreads (10 dB) are less than 16 ps. The worst case measurement with line-of-sight to the Frankfurt skyline produced a multipath component 7 dB below the direct component at an excess delay of 51.3 ps. The worst case rms delay spread is 19.6 ps. Radar cross sections (RCS) of common scatterers in cellular and microcellular radio channels are shown to range between-4.5 and +55.7 dBm2.

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This study presents an original optical system designed for measuring the free surface velocity for shock wave diagnostics. The system is based on a solid Fabry-Perot etalon interferometer coupled to a tunable, single frequency laser. The setup assembled for this purpose can measure velocities up to 200 m s −1 and has a resolution time of about 1 ns. This system was validated in shock experiments performed on thin aluminum samples. The shock waves were generated by a pulsed laser on a water confinement configuration and the surface velocity was measured on the opposite side of the sample. The signals obtained are in good agreement with numerical simulation and results found in the literature. This system presents an interesting alternative to the velocity interferometer system for any reflectors (VISAR) commonly used in shock experiments.

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