| 摘要 |
A noise-cancelling pickup for a stringed instrument uses two transducers to monitor different forces exerted by a vibratable string under tension. The first transducer is responsive to the music vibrations of the vibrating portion of the string but it is also responsive to variations of the string tension which are not related to the music vibrations of the string. The second transducer is mainly subjected to the variations of the string tension which are not related to the desirable music vibrations. The signals from the transducers are combined in and out-of-phase manner to produce a joint signal in which the spurious components corresponding to the variations of the string tension are significantly attenuated and possibly eliminated.
|
