GB1465189A - Musical instruments - Google Patents

Abstract

1465189 Arpeggio generator NORLIN MUSIC Inc 27 March 1974 [7 May 1973] 13640/74 Heading G5J In a musical instrument arpeggios can be generated over one, two or three octaves from the notes actuated on a sequentially scanned keyboard, the scanning being halted for a predetermined interval each time an actuated key is scanned thus giving a constant duration to the generated notes. When the foot switch 90 is opened, a scan oscillator generates pulses, preferably at about 1kHz., which are applied to an up-down 4-bit counter 28 via two buffers 32, 33 one of which is actuated by a panel switch 42. The counter outputs are connected to a 1-of-16 decoder 18, twelve of the outputs 20 drive gates 14 while a thirteenth 19 pulses a 3-bit counter 76 which thus records the number of scans made over the twelve outputs. A lower-manual keyboard 22 having twelve keys is connected to the gates 14 also and a combination of an operated key and a scan signal on the corresponding line of 20 opens the relevant gate allowing a control signal to pass to the arpeggio keyer 10. This routes the signal to one of 36 lines according to the outputs of the octave enable control 84. The panel mounted mode selector switches 42 define the number of octaves to be scanned over and as each scan is completed, counter 76 increments varying the signals on 80, 82 to enable a different octave output from the arpeggio keyer. When the chosen arpeggio pattern has been completed all outputs 12 are cut off. Closure of foot switch 90 resets both counters 28 and 76 and simultaneously stops the arpeggio in mid-flight. The thirty-six outputs 12 are connected to conventional keyers (not shown) placed between a tone source, voicing elements, and an audible output (none shown). When any actuated key is scanned a signal is supplied on line 66 from the gates 14 to enable strobe switch 62 which on the next negative transition of the scan oscillator 44 passes the signal to the up-down-transfer-stop disable 70 and this triggers the start-stop flip-flop 52 to inhibit further transitions from the scan oscillator 44. After a time set by the arpeggio speed control 58 a timer multivibrator 54, which preferably runs at about 4Hz., changes state resetting the flip-flop 52 allowing scan oscillations to restart. Thus any operated key results in an output keying signal at 12 which lasts for a time set by the arpeggio speed control 58. Among the patterns of arpeggio that can be obtained are some passing up through octaves and then back down again. To avoid sounding the same note twice, once before and once after reversal, a change of signal on line 40 not only changes the counter inputs over by controlling the buffers 32, 33 but is also applied to the updown-transfer-stop-disable 70 on line 74 and inhibits the passage of the strobe switch 62 output, thus the scan oscillator is not halted. Detailed circuitry is given in Figs. 2A to 2E (not shown).