| 摘要 |
A stroboscope device for a record player for monitoring at least two speeds such as 331/3 and 45 r.p.m. A turntable rim may be provided with a single stroboscope pattern for the relevant speeds. As they pass a light pulse generator, the marks of the stroboscope pattern are optically comparable with light pulse trains produced by a light pulse generator at one of a plurality of frequencies obtained from a given or a-c mains frequency.
|
