| 摘要 |
1416266 Electronic musical instrument CHICAGO MUSICAL INSTRUMENT CO 31 Jan 1973 [14 July 1972] 4788/73 Heading G5J Automatic rhythm is added to organ output by a rhythm pattern generator which sounds alternately the highest and lowest notes keyed on the lower manual keyboard. Outputs 28, 32, 33, 34; not necessarily in the same pattern, come from rhythm generator 27. Units 29 and 46 modify the tone quality and envelope of the rhythm sound according to outputs 28 and 34. Output 32 drives unit 31 which simulates manual playing in the rhythm pattern while keys are continuously depressed. Output 33 feeds two-phase driver 40 in which transistors (70), (74) (Fig. 2, not shown) conduct alternately, supplying antiphase rhythm potentials to identical current sources 41, 42, one of which will always be supplying a constant 5 ma. to unit 37. A selected number (e.g. 25) of the keyswitches in lower manual 15 supply current to a series of transistors in 37, and in the absence of current to 37 from sources 41 or 42 would cause rhythm tones to sound, supplied by tone sources 25. Bases of the transistors in 37 are connected to stages of parallel opposing chains of diodes, fed at the ends from 41 and 42. Potential drops along the chains ensure that when current is supplied from 41, only the lowest pitch activated note controlled by the transistors will sound its rhythm equivalent, and for 42 only the highest. Bus 44 then adds rhythm tones to the filter and preamp unit 20, where it is modified by the rhythm controls from units 29 and 46, and output from tab switches 17 and 19 is combined. Output from tab switches 18 may be replaced by the automatic accompaniment from unit 31, driven by rhythm output 32.
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