| 摘要 |
1523782 Metronomes J M DEL CASTILLO 4 Aug 1975 [6 Aug 1974 (2) 30 Aug 1974] 32586/75 Heading G3T [Also in Division G5] An optical metronome 20 has means for successively illuminating discrete areas of a face 23 intended to receive a translucent sheet 22 marked with vertically spaced staves and with musical notation, the illuminated areas thus indicating the note to be played and its desired duration. As shown an illuminated spot 27 is produced simultaneously in each of the staves by light transmitted through optical fibres the ends of which are referenced 26. The other ends of the fibres receive light passing through a perforated plate (33), Fig. 3, 4 (not shown) which is rotated by an adjustable speed motor (31). Illumination of the fibres may alternatively be produced by lamps (46), Figs. 6, 7 (not shown) which are switched on and off in succession. In other alternatives the fibres are omitted and lamps are placed behind the metronome face, e.g. in vertical reflecting channels. The lamps are energized via a motor driven contact or via logic circuitry Figs. 14, 15 (not shown) using an oscillator and frequency dividers. |
