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Polyphonic computer organ
| Details |
Inventors: Deforeit, Christian J.;
Assignee:
Primary Examiner: Schaefer; Robert K.
Assistant Examiner: Miska; Vit W.
Attorney, Agent or Firm: Oblon, Fisher, Spivak, McClelland & Maier
A polyphonic electronic musical instrument in which the complex signal delivered by the instrument is made up of successive samples. Each sample in the complex signal is the sum of the samples of the different harmonics of the various notes played, at the corresponding amplitudes. A device for scanning the keys and pedals comprises two or three counters which operate in association with one another to detect the number (i) of each played note out of the 12 or 13 notes in an octave, and also detect the number of the corresponding octave (n) and successively calculate the various samples of the harmonics of the note (i, n). The set of operations is performed in a sufficiently short time to produce notes of 6- 10 kHz. |
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DETAILED DESCRIPTION The musical instrument according to the invention is a truly polyphonic instrument which is not subject to the limitations of the prior art.
Its operation is completely numerical and it can produce samples of all the frequencies of all the played notes, add them and convert the results to analog signals at a sufficiently high rate for properly transmitting frequencies of the order of 6 to 10 kHz.
The musical instrument according to the invention can use a large number of keys and pedals without complicated wiring, since only a few tens of connections have to be made.
It can produce a large number of harmonics in addition to the fundamental note corresponding to each selected key, and the amplitude of each harmonic can be chosen.
In addition, the attack and extinction characteristics of each harmonic component of the sounds produced can be chosen.
Accordingly, the instrument can produce any wave form and reproduce any timbre of most instruments.
It can also, like those instruments called synthesizers, produce timbres which do not correspond to any existing instrument.
As before, the reproduction can be polyphonic.
The musical instrument according to the invention uses a small number of circuits which are completely numerical and consequently suitable for integrated components.
Thus, a set of circuits occupies a small space and the assembly and wiring operations can be greatly reduced.
In addition, all or part of the instrument can be incorporated in a single circuit.
The instrument according to the invention comprises a device which scans the manual keyboard or keyboards and the pedal board, if any, and, for each selected note, calculates the sample of the fundamental frequency and of the harmonics, with their respective amplitudes.
All the samples of all the preselected harmonics of all the played notes are calculated and added together during a repetition period which is substantially less than the half-cycle of the highest-frequency harmonic which the instrument can produce
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CPUs 
