JPS604997B2 - sound source circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sound source circuit, particularly a novel sound source circuit suitable for sound sources such as electronic musical instruments.

Conventionally, electronic musical instruments have often used square waves or chain-tooth waves as sound sources. These are because the frequency division method is easy and gates such as sustain gates can be made relatively easily. The harmonics of a square wave sound source or a mirror-tooth wave sound source have the ratio B/t. It is attenuated by

A curve 51 in FIG. 1 shows how the harmonics are attenuated. As can be seen from FIG. 1, the disadvantage of the square wave and mirror-tooth sound sources is that the harmonics near the fundamental wave are small and the higher harmonics are large. As a result, the sound had a weak sound because the harmonics near the fundamental wave were small, and conversely, the high harmonics did not attenuate easily, resulting in a strong mirror sound that was difficult to hear. The present invention provides a sound source that eliminates the above-mentioned drawbacks found in conventional square wave and sawtooth wave sources.

One of the objects of the present invention is to provide a sound source circuit in which the n-th harmonic of one input signal is attenuated at a rate of rn (0 x 1).

Another object of the present invention is to provide a sound source circuit that can vary the behavior of harmonics. That is,
The present invention includes a scale signal generator, a constant generator, and a first coefficient circuit that receives each output signal of the scale signal generator and constant generator as input, and a first coefficient circuit that receives the output signal of the scale signal generator as input. a second coefficient circuit; a third coefficient circuit that receives the output signal of the first coefficient circuit; a fourth coefficient circuit that receives the output signal of the third coefficient circuit; a coefficient circuit and a multiplier that mutually multiplies each output signal of the third coefficient circuit, the output signal of each of the multiplier and the fourth coefficient circuit being input to the second coefficient circuit. It is characterized by the fact that

A potentiometer, a normal multiplier, or the like is used as the above-mentioned coefficient circuit.

The present invention will be explained below based on drawings of embodiments.

FIG. 2 is a diagram showing an embodiment of the present invention. In FIG. 2, 1 is a scale signal generator, and 2 is a constant generator, which generates a predetermined DC potential.

The outputs of the scale signal generator and the constant generator are connected to a first coefficient circuit 3 and are each multiplied by a predetermined coefficient. The output of the first coefficient circuit is connected to the waveform conversion circuit 8 and then outputted, and at the same time, it is connected to the third coefficient circuit 4 and multiplied by a predetermined coefficient. The output of the third coefficient circuit 4 is connected to the fourth coefficient circuit 5 and multiplied by a predetermined coefficient, and simultaneously connected to the multiplier 7 and multiplied by the output signal of the second coefficient circuit 6. The output signal of the fourth coefficient circuit 5 is transmitted to the first coefficient circuit 3.
is connected to and multiplied by a predetermined coefficient. Scale signal generator 1
The output signal of is also connected to a second coefficient circuit 6, and the output of the second coefficient circuit is connected to a multiplier 7, where it is multiplied by the output signal of the fourth coefficient circuit 5. The output signal of the multiplier 7 is connected to the first coefficient circuit 3 and multiplied by a predetermined coefficient. In FIG. 2, it is assumed that the output signal of the scale signal generator 1 is cos t and the output signal of the constant generator 2 is -1.

It is also assumed that the first to fourth coefficient circuits are constructed from arithmetic multipliers as shown in the figure. The output signal of the scale signal generator 1 is connected to the resistor 1
2 and the resistor 11, ie, for example, the crab KQ/10 plate is multiplied by a coefficient of 0. The same applies to other coefficient circuits.
Now, the ratio of the above resistance 1 2, 1 1 8 arc ○/10 female Q is r
Then, the output Y' of the first coefficient circuit is generally given by the following equation. Y'=〆Y'10th Duke Y'cos t+11rC
OS's t.-rCOS's t.・．． Y'=・-cos t+r2 Also, from Fourier analysis,・-rCOS t Y=・-cos t+r2= n≧, r and osn■t
(However, OSr<1) As described above, the sound source circuit according to the present invention outputs a signal in which the n-th harmonic is given by rn for one input vermilion sinusoidal wave.

The intensity relationship between the fundamental wave and harmonics of the output signal of the sound source circuit according to the present invention is shown by a curve 52 in FIG. Further, the waveform of the output Y' is shown in FIG. As can be seen from the curve 52 in FIG. 1, when the output signal of the scale signal generator is a cosine wave, the sound source circuit according to the present invention generates a signal Y'=nZ,rncosnt as an output.

The sound produced by a sound source with a harmonic series such as curve 52 in Figure 1 is richer than the sound produced by conventional square waves or mirror-tooth waves, and produces an unpleasant chi'' sound in the high range. The result is an excellent sound that doesn't linger.

Even if it is not a perfect cosine wave, it can be used as the output signal of a scale signal generator. When a perfect square wave was input as the output signal of the scale signal generator, the behavior of the harmonics became very complex, but the tendency that the harmonic level near the fundamental wave increased was maintained. As a matter of course, by changing the setting values of the coefficient circuit from the outside, the timbre of the sound to be produced can be changed to medium or large.

The output of Y basically has harmonics like the curve 52 in FIG. 1, but there are many cases where it is desired to slightly increase the level of the high harmonics as a sound.

The present invention uses a waveform conversion circuit 8 for this purpose.
In the embodiment, a diode 15, a variable DC voltage setting device 16, and a resistor 13 are used to clip the top of the waveform shown in FIG.
A clip circuit consisting of 14 circuits is used. As described above, the sound source circuit according to the present invention uses a sound source that has a high harmonic level near the fundamental wave and a low harmonic level of higher orders, and a waveform converter that has a high harmonic level near the fundamental wave and a low harmonic level of higher orders. It is possible to provide a sound source with a high harmonic level, and a sound source whose harmonic behavior can be changed over a wide range by externally changing the coefficients of the coefficient circuit, and has extremely high practical value, especially in the field of electronic musical instruments.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the state of harmonic attenuation by comparing an example of a conventional sound source and a sound source obtained by the present invention, and FIG. 2 is a diagram showing an embodiment of the present invention. FIG. 3 is a waveform diagram showing an example of a sound source circuit according to the present invention. 1... Scale signal generator, 2... Constant generator, 3, 4, 5, 6... Coefficient circuit, 7...
... Multiplier, 8... Waveform conversion circuit. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A scale signal generator, a constant generator, a first coefficient circuit receiving each output signal of the scale signal generator and the constant generator, and an output of the scale signal generator. a second coefficient circuit that receives the signal as input; a third coefficient circuit that receives the output signal of the first coefficient circuit as input; and a fourth coefficient circuit that receives the output signal of the third coefficient circuit as input. and a multiplier that mutually multiplies each output signal of the second coefficient circuit and the third coefficient circuit, and the output signal of each of the multiplier and the fourth coefficient circuit is also multiplied by the output signal of the first coefficient circuit. A sound source circuit characterized in that it is input to a coefficient circuit. 2. The sound source circuit according to claim 1, wherein the output is extracted from the output of the first coefficient circuit. 3 The coefficient of the first coefficient circuit is set to about -1 for the multiplier output signal and the output signal of the fourth coefficient circuit, and the coefficients of the second to fourth coefficient circuits are set to about +2 and -1, respectively. r, -r
The sound source circuit according to claim 1, characterized in that (r>0). 4. The sound source circuit according to claim 1, wherein the output signal of the scale signal generator has a cosine wave or a waveform close to a cosine wave with relatively few harmonic components. 5. The sound source circuit according to claim 1, characterized in that a waveform conversion circuit is connected to the output end of the first coefficient circuit, and converts the output of the first coefficient circuit into a waveform and outputs the resultant waveform conversion circuit. 6. The sound source circuit according to claim 4, wherein a clip circuit whose clip position can be controlled is used as the waveform conversion circuit. 7. The sound source circuit according to claim 1, wherein the coefficients of the coefficient circuit can be controlled from the outside.