| 摘要 |
PCT No. PCT/GB82/00337 Sec. 371 Date Jul. 25, 1983 Sec. 102(e) Date Jul. 25, 1983 PCT Filed Nov. 26, 1982 PCT Pub. No. WO83/02031 PCT Pub. Date Jun. 9, 1983.Primary vibrations from a repetitive source of such vibrations are nulled in a location by specially generated secondary vibrations fed to the location from an actruator. The actuator is driven by a waveform generator which is synchronized to the source by a synchronizing signal on the line which is derived otherwise than from the source. In FIG. 2, the synchronizing signal is derived from the output of a residual vibration sensor via a filter or a phase-locked loop (FIG. 3 and 4). |
