DE2210233A1 - Tone generator for electronic musical instruments - Google Patents

Description

Poikstioßö

6991

NIPPON GAKKI SEIZO KABUSHIKI KAISHA, Shizuoka-Ken, Japan
Tone generator for electronic musical instruments

The invention relates to a tone generator for electronic Musical instruments with control oscillators of different oscillation frequencies and with the control oscillators connected downstream Control frequency dividers, each assigned to a note in an octave.

A previously proposed tone generator for electronic
Musical instruments contain a control oscillator, twelve control frequency dividers that divide the frequency of the control oscillator into the twelve tones C, C ^# , D, D *, E, F, F ^, G, (f , A, A ^# and B in the highest octave of the Musical instrument and a row
of 1/2 frequency dividers, each having the frequency of one
divide the twelve tones in a previous octave into the corresponding tone of the following octave.

However, since the frequency division factors (ratios) of the control frequency divider should be integers, certain errors always occur in the tones resulting in the above manner, although the oscillation frequency of the control oscillator is much higher than the audio frequencies. If the frequency errors are small it is necessary to set the frequency of the control oscillator and thus also the frequency division factors of the control frequency divider to choose very high or large. Such a structured one

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However, the tone generator is extremely complex.

The invention has for its object to provide a tone generator for electronic musical instruments in which the smaller Frequency errors occur in the generated tones and still have a simple structure with a smaller number of Has circuit elements.

To solve this problem, the initially described tone generator according to the invention is characterized in that the Output frequency of a first control oscillator feeds a first group of control frequency dividers, which every second Note assigned in the octave, and that the output frequency of a second control oscillator is a second group from control frequency dividers that feed the other notes assigned in the octave.

In this way you get different control oscillators with two control oscillators Output frequency an extremely simply constructed tone generator, in which the occurring frequency errors are low are.

The basic principle and a possible application of the subject matter of the invention are illustrated in the form of an exemplary embodiment described by figures.

Fig. 1 shows the block diagram of an already proposed Tone generator for electronic musical instruments.

FIG. 2 shows the block diagram of a tone generator for electronic musical instruments constructed according to the invention .

The proposed tone generator shown in Fig. 1 contains a control oscillator 1, the output frequency of which is from twelve control frequency dividers 2C, 2C ^, 2D, 2D * \ 2E, 2F, 2F ^, 2G,

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2G ", 2Α, 2Α 'and 2Β is divided into twelve tones corresponding to the twelve Notes correspond to the highest octave of a musical instrument. The frequencies of these twelve tones are then divided by 1/2 frequency dividers 3 halved to produce the notes of the following octaves.

For example, if the tone frequencies given in Table 1 are used who wants to produce twelve notes in the highest octave and selects the frequency of the control oscillator to 1.94-45 MHz, receives the frequencies given in table 2 are used for the twelve tones.

Table 1

grade C. 4435.0 D. D ^r E. F. - F ^ G G ^ A. A ^ ι Β 7902.1 Table 2 grade C. 438 D. 391 E. F. frequency
(Hz) 4186.0 4698.5 4978.0 5274.0 5587.7 5919.9 6271.9 6644.9 7040.0 7458.6 Divider
factor 464 4439.4 414 4973.1 369 348 frequency
(Hz) 4190.7 +1.71 4696.8 -1.67 5269.6 5587.6 failure
(Cent) +1.88 -0.65 -1.42 -0.02

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(Continued) Table 2

grade 328 G G ^ A. A * B. Divider
factor 5928.3 310 293 276 261 246 frequency
(Hz) +2.37 6272.5 6636.4 7045.2 7450.1 7094.4 failure
(Cent) +0.15 -2.13 +1.24 -1.92 +0.48

From these tables it follows that at a frequency of the control oscillator of 1.9445 MHz and with a choice of integer frequency division factors the frequency errors in a range of -2.13 to +2.37 cents fall. The total error range is thus 4.50 cents.

But now you can hear frequency errors of more than 3 cents. It is therefore desirable to limit the error range less than 3 cents to decrease. In order to achieve this with the proposed tone generator, one would have to adjust the frequency of the control oscillator increase considerably and accordingly also larger frequency division factors for the control frequency divider Select. However, such a structure would not be economically justifiable.

In Fig. 2 is a preferred embodiment of the invention shown. In this embodiment come on

■ dl ·

twelve control frequency dividers 5C, 5C, 5D, 5D, 5E, 5F, 5F% 5G, 5G ^, 5A, 5A ^ and 5B two control oscillators 6 and 7> of which the one control oscillator 6 every second of the frequency dividers, for example 5C, 5D, 5E, 5F ^, 5G ^ and

while the other

Control oscillator 7 feeds the other control frequency dividers, that is to say the frequency dividers 5C ^, 5D ^, 5F, 5G, 5A and 5B.

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In order to generate the frequencies of the twelve notes of the highest octave contained in Table 1, one can use the frequency fM ^ of the first control oscillator 6 with 1.8335 MHz and the Frequency fjyu of the second control oscillator 7 at 1.9425 MHz Select. The ratio of fMp / fl'L = 1.0594 and corresponds to thus a semitone. With the appropriate choice of integer divisor factors, the fourths above give the data compiled in Table 3.

Table 3

grade C. 438 I.
(
D. D ^ E. F. F ^ G G ^ A. 246 B. Divider
factor 438 4435.0 391 391 348 348 310 310 276 276 7453.1 246 \
i frequency
(Hz) 4186.0 0 4689.2 4968.1 5268.6 5582.0 5914.4 6266.2 6643.0 7038.2 -1.20 7896.5
i failure
(Cent) 0 -0.91 -0.91 -1.73 -1.73 -1.50 -1.50 -0.47 -0.47 -1.20

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As can be seen from Table 3, the frequency division factors for the first group of control frequency dividers are 5C, 5D, 5E, 5F ^, 5G ^ and 5A ¹ ^ with the frequency division factors for the second group of control frequency dividers 5C ^{) r} , 5D ⁷ '", 5F, 5G, 5A and 5B are identical and cover a range from 438 to 246.

A comparison between Tables 2 and 3 shows that the sound frequencies compiled in Table 1 are generated with the structure according to the invention in a simple manner can considerably reduce the errors in the individual notes. The errors that occur range from 0 to -1.73 cents, i.e. they fall within a frequency error range of only 1.73 cents. The frequency errors for the individual tones are thus significantly lower in the embodiment according to the invention according to FIG. 2 than in the already proposed Tonge, generator according to Fig.1.

Furthermore, the comparison between Tables 2 and 3 shows that the frequency division factors for obtaining all twelve notes in Table 3 are equal to or smaller than the frequency division factors in Table 2. From this it follows that one with the constructed according to the invention tone generator with a significantly lower number of circuit elements than in the proposed arrangement.

Furthermore, as already mentioned, the frequency divider factors of the first group are control frequency dividers with the frequency divider factors the second group of control frequency dividers identical. Each control frequency divider in the first divider group can therefore be exchanged with the corresponding one in the second divider group. This results in simplifications and savings in the design and manufacture of the control frequency divider.

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Claims (3)

Claims Tone generator for electronic musical instruments with control oscillators different oscillation frequencies and with several control frequency dividers connected downstream of the control oscillators, each assigned to a note in an octave, characterized by that the output frequency of a first control oscillator (6) a Yj ₁ . first group of control frequency dividers (5C, 5D, 5 A) feeds which are assigned to every second note in the octave, and that the output frequency of a second control oscillator (7 ^{) feeds a second group of control frequency dividers (5C, 5D 1} ^, 5B) which are assigned to the other notes in the octave 2. Tone generator according to claim 1,
characterized in that a total of twelve control frequency dividers are provided, which are assigned to the twelve notes in the octave, and that the first and second groups of control frequency dividers each consist of six dividers. 3. Tone generator according to claim 1 or 2, characterized in that that the octave comprises the highest frequencies of the electronic musical instrument and that the notes of the following octaves by repeatedly halving the tone frequencies of the highest octave can be generated using multiple 1/2 tone frequency dividers. 209838/0825 L θ e r s e i ί e