| 摘要 |
A marine seismic source 100 includes a flextensional shell 2 which has a longer axis and a shorter axis. At least one driver 8 is coupled to the flextensional shell 100 proximate an end of the shorter axis. The driver may be a moving coil driver having magnetic circuitry 14, an electric coil 10 and a transmission element 11. The source may have a single bi-directional driver 8, or one or more uni-directional drivers. The driver 8 may be suspended on a fixture 4 which extends along the major axis of the shell and which is mounted to hinges 12 using linear bearings 6. At least one inner spring (16,Fig.2) is coupled to the flextensional shell and there are a plurality of masses coupled to the inner spring. The spring may be elliptically shaped. The spring gives rise to a second system resonance. The source may then have two resonant frequencies in the range 1 to 50 Hz. The shell is preferably elliptical but may also be concave, convex or flat (see fig. 1A). |
