| 摘要 |
1462019 Electrophonic musical instruments WURLITZER CO 14 March 1975 [1 May 1974] 10832/75 Heading G5J In an automatic rhythm control circuit different value frequency signals are received by memory circuits which pass these signals at preset time intervals during time-frame scanning, while gate circuits controlled by a selector switching circuit enable the preset time intervals to follow rhythmic patterns. A divider circuit (Fig. 1, not shown) with an input of 500 kHz produces a plurality of frequencies corresponding to different instrument sounds (drums, cymbals &c.), while a counter and decoder circuit (Fig. 2, not shown) has 24 output lines connected to the scanning terminals of a matrix-array memory circuit 70, part of which is shown in Fig. 3 (the remainder being in Figs. 4-5, not shown), having 73 (22 shown in Fig. 3) output lines connected to various AND gate circuits; the cross over points of the lines thus provide 1752 bit storage usable in a programmed manner. The circuit 70 comprises sub-groups 71, 96, 108 &c. having characteristics associated with a base drum, cymbal, brush &c., sub-group 71, e.g. having five outputs connected to AND circuits 72-76 connected to the outputs of inverter circuits 77-81 which are selectively switchable to inputs 82-86 for obtaining march, waltz, rock, swing and Latin rhythm. During a timeframe interval scanning pulses from the counter and decoder circuit are fed to the memory circuit 70 by the 24 lines, one of which is active at a time; when a rhythm is switched on, one input of one gate 72-76 are active to deliver a signal via OR gate 91 and AND gate 92 (which has a line 93 receiving a pulse width signal from the counter circuit) to a terminal 94 to activate a drum signal.
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