| 摘要 |
A LSI (large scale integrated circuit) device is disclosed which generates 12 output frequencies related to each other by a multiple of the twelfth root of two from a common time base without the use of parallel divider or shift register strings. The output frequencies comprise the top octave, or a multiple thereof, of the frequencies of an electronic musical instrument. A binary counter serves as a common time base and encodes each wave form period in a form of a binary code. A binary processing circuit associated with each output frequency stores the count position of the next desired wave form transition and updates the stored code after each transition has occurred. The binary processing circuitry comprises a latch circuit, a binary full adder or ROM (read only memory), a digital comparator or ROM, and a J-K flip-flop circuit. The outputs can be easily modified in both actual frequency and waveform symmetry.
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