| 摘要 |
A quasi-static gravity gradients comprising: a flexible ribbon 3 held under tension at both longitudinal ends 5 and sensing means 20 to detect the transverse displacement of the ribbon from an undisturbed position due to the gravitational field acting on said ribbon and to generate a signal representing the displacement. Output means are coupled to sensing means 20 and are responsive to the displacement signal to generate an output signal which is a function of the gravitational gradient tensor of the gravitational field. To modulate the response of the apparatus to gravitational gradients, the apparatus further comprises ribbon stiffening means. These are operable to change the ribbon from a normal state to a stiffened state thereby reducing the displacement of the ribbon due to the gravitational field. Control means 13 are provided to periodically operate the stiffening means 10 at a frequency equal to the resonant frequency of the ribbon. An output means demodulates the displacement signal by synchronous detection using a signal representing the modulation of the ribbon stiffness. |
