JP2001100752A - Effect adding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an effect adding device for generating a sense of distortion such as a real guitar amplifier with a simple circuit. SOLUTION: This device is provided with a saturating circuit 402 for saturating a signal, and for outputting it as a saturated signal and an integrating circuit 101 for integrating the saturated signal according to the alternate state of the saturated signal. For example, the saturating circuit 402 saturates an input signal such as a guitar sound according to the level of the input signal, and outputs it as the saturated signal. Then, the integrating circuit 101 integrates the saturated signal according to the alternate state, and converts it into a signal with hysteresis. Thus, it is possible to realize 'distortion with hysteresis' being the characteristics of the distortion of a guitar amplifier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an effect adding device (effector) used for a sound source of an electronic musical instrument, and more particularly to a distortion effect (a so-called distortion) frequently used for a tone color of an electric guitar or the like.

[0002]

2. Description of the Related Art A conventional effect adding device will be described below.
This will be described with reference to the drawings.

FIG. 4 is a block diagram showing a configuration of a conventional effect adding device. In FIG. 4, reference numeral 401 denotes an analog-to-digital converter (AD) for converting an input signal into a digital signal.
C), 402 is a saturation circuit for saturating the output signal of the analog-to-digital converter 401, 403 is a filter for filtering the output signal of the saturation circuit 402, and 404 is a digital-to-analog converter for converting the output signal of the filter 403 to an analog signal. (DAC). Note that the saturation circuit 4
02 is a non-linear table converter. The filter 403 is assumed to be a band emphasis filter that emphasizes a specific frequency band (about 3 kHz). Since the circuit configuration of the band emphasis filter is generally well known, the description is omitted.

FIG. 5 is a conversion characteristic diagram of the saturation circuit 402. The horizontal axis of this conversion characteristic corresponds to the table address,
The vertical axis corresponds to the table data.

FIG. 6A shows an input signal and a saturation circuit 4.
It is a time waveform chart showing the waveform of the output signal of No. 02. The solid line is the output signal of the saturation circuit 402, and the broken line is the input signal. The input signal is a sine wave of about 250 Hz. FIG. 6B is a time waveform chart illustrating the waveform of the output signal of the filter 403. FIG. 6C shows the filter 403.
FIG. 3 is an amplitude frequency spectrum diagram showing a frequency spectrum of the output signal of FIG.

The operation of the conventional effect adding apparatus having the above-described configuration will be described.

First, the overall operation will be described with reference to FIG. The analog-to-digital converter 401 converts a sine wave of about 250 Hz given as an input signal into a digital sine wave signal (hereinafter simply referred to as a sine wave signal). As shown in the characteristic diagram of FIG. 5, the saturation circuit 402 distorts the sine wave signal so as to saturate a portion where the absolute value of the amplitude level is large. As a result, as shown by the solid line in FIG.
A saturated signal (square waveform) is obtained. The characteristic of this waveform shape is a line-symmetric shape with the peak value of the input signal (sine wave signal) as a boundary. Filter 4
03 emphasizes about 3 kHz, a waveform shown in FIG. 6B is obtained, and is output to the outside via the digital-analog converter 404. Note that the filter 403 has a role of tone adjustment (equalizing), for example, about 1 k.
When it is desired to have a tone color in which Hz is emphasized, it can be realized by adjusting the coefficient of the filter 403 (detailed description is omitted). Filter 4
03 is the amplitude frequency spectrum of the output signal of FIG.
As shown in (C), the odd harmonics are generated by the saturation processing, and the filter 403 has a spectrum structure in which the vicinity of about 3 kHz is emphasized.

[0008]

However, the conventional configuration as shown in FIG. 4 results in a tone composed only of odd-numbered overtones, resulting in a distortion that is not very audible. In terms of auditory sense, for example, a guitar amplifier using a vacuum tube or the like has an excellent distortion feeling, and the characteristic feature is distortion including even-order harmonics. In terms of time waveforms, the saturation shape is not a line symmetry as shown in FIG. 6 (A), but has a hysteresis characteristic in a waveform shape such as falling right or rising right, that is, a conversion characteristic in a saturation circuit. The resulting distortion. Hereinafter, simply "distortion with hysteresis"
And

The present invention solves the above problems,
Provided is an effect adding device that generates a distortion waveform having hysteresis, that is, generates even-order harmonics, and consequently simulates the distortion feeling of a guitar amplifier with a simple circuit.

[0010]

In order to achieve this object, in the musical sound synthesizer of the present invention, an integrating means is inserted after a saturating circuit, and the integrating means converts a saturated signal output from the saturating circuit. By integrating the saturation signal in accordance with the alternating state, distortion with hysteresis is generated.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a saturating means for performing a saturation process on an input digital signal and outputting the same as a saturated signal, and an integrating means for integrating the saturated signal in accordance with an alternating state of the saturated signal. And filtering means for filtering a signal as an integration result of the integrating means.

According to this configuration, the integrating means integrates the saturation signal in accordance with the alternating state of the saturation signal to generate distortion with hysteresis, and as a result, a tone close to the distortion feeling of the guitar amplifier can be obtained. it can.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an effect adding device according to an embodiment of the present invention. In FIG. 1, reference numeral 101 denotes an integration circuit for integrating a saturation signal output from the saturation circuit 402. Other circuits are the same as those of the conventional effect adding device.

FIG. 2 is a block diagram showing the configuration of the integration circuit 101. In FIG. 2, 201, 205, 206
Is a multiplier, 202 and 203 are adders, 204 is a delay unit for delaying by one sampling time, 207 is a comparator, 20
8 is a gate circuit.

FIG. 3A is a time waveform chart showing the waveform of the output signal of the integrating circuit 101. FIG. 3 (B)
FIG. 7 is a time waveform chart illustrating a waveform of an output signal of a filter 403. FIG. 3C is an amplitude frequency spectrum diagram showing the frequency spectrum of the output signal of the filter 403.

The operation of the effect adding apparatus according to the present embodiment configured as described above will be described. First, FIG.
The overall operation will be described with reference to FIG.

Basically, a sine wave of about 250 Hz is input as in the conventional effect adding device shown in FIG. afterwards,
A desired output signal can be obtained via each block, but the point different from the conventional one is that the integration circuit 101 integrates the saturation signal output from the saturation circuit 402.

Next, the operation of the integrating circuit 101 will be described with reference to FIGS. In FIG. 2, multipliers 201,
A closed loop circuit composed of an adder 205, an adder 202, and a delay unit 204 is a generally known integration circuit.
The gain of the multiplier 201 determines the gain of the integration signal, and the gain of the multiplier 205 determines the degree of integration. Simply with this configuration, a signal obtained by delaying the phase of the saturation signal by 90 degrees is obtained as an integrated signal, and as a result, hysteresis cannot be added.

In the present invention, the adder 203,
By adding the multiplier 206, the comparator 207, and the gate circuit 208, integration according to the alternating state of the saturation signal is performed. First, the saturation signal (square wave-shaped waveform shown in FIG. 6A as in the conventional case) is gain-adjusted by the multiplier 201 and then integrated, and the output value of the adder 202 gradually increases in the positive direction. I will do it. This value is multiplied by the saturation signal in the multiplier 206, and the result is input to the B input of the comparator 207. While the saturation signal has a positive value, A <
Since B (here, A is a value of 0), the gate circuit 208 is in a closed state, and the addition by the adder 203 is not performed. This corresponds to the section A shown in FIG. Thereafter, when the saturation signal becomes a negative value, that is, when the time corresponding to a half-wave has elapsed, the multiplication result of the multiplier 206 becomes negative, so that the comparison signal (A> B) of the comparator 207 becomes active, The gate of the gate circuit 208 opens, and the saturation signal is added by the adder 203. Since the saturation signal has a negative value, the integral value decreases. This corresponds to the section B shown in FIG. When the integration signal becomes negative, the saturation signal is still a negative value. Therefore, the multiplication result of the multiplier 206 becomes positive again, the gate circuit 208 closes, and the integration starts in the negative direction. This is A 'in FIG.
Corresponds to the section.

By repeating the above, FIG.
An integrated signal as shown in FIG. That is, distortion having hysteresis is generated.

That is, when the polarity of the saturation signal is inverted and the result of the multiplication by the multiplier 206 is positive, the integration circuit 101 causes the integrated value to approach the saturation signal in a time sufficiently shorter than one cycle time of the saturation signal. When the polarity of the saturation signal is inverted and the result of the multiplication by the multiplier 206 is negative, the integrated value gradually approaches the value 0 in a time sufficiently shorter than one cycle time of the saturation signal.

In the integrated signal output from the integrating circuit 101, a band component of about 3 kHz is emphasized in the filter 403.
A waveform as shown in FIG. 3B is obtained. This waveform is the desired sound, and its amplitude frequency spectrum is shown in FIG.
As shown in FIG. 7, the characteristic is such that even-order harmonics are formed.

As described above, according to the embodiment of the present invention, the integration circuit 101 enters the normal integration state according to the alternating state of the saturation signal, that is, the change in the polarity, or integrates according to the saturation signal. By repeatedly reducing or increasing the value, distortion having hysteresis is generated, and as a result, a distortion waveform including even-order harmonics is generated.

In this embodiment, for convenience of explanation,
Although a sine wave is input, a musical sound such as a guitar may be input.

[0026]

According to the present invention, there are provided a saturating means for performing a saturation process on an input digital signal and outputting the same as a saturated signal, an integrating means for integrating a saturated signal according to an alternating state of the saturated signal, and an integrating means. Filter means for filtering a signal as a result of the integration, and the integration means integrates the saturation signal in accordance with the alternating state of the saturation signal to generate distortion with hysteresis, and as a result, A tone close to a sense of distortion can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an effect adding device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an integrating circuit of the effect adding device.

FIG. 3 is a diagram showing a time waveform and an amplitude frequency spectrum for explaining the operation of the effect adding apparatus.

FIG. 4 is a block diagram showing a configuration of a conventional effect adding device.

FIG. 5 is a conversion characteristic diagram showing characteristics of a saturation circuit of a conventional effect adding device.

FIG. 6 is a diagram showing a time waveform and an amplitude frequency spectrum for explaining the operation of the conventional effect adding device.

[Explanation of symbols]

 Reference Signs List 101 integration circuit 201, 205, 206 multiplier 202, 203 adder 208 gate circuit 401 analog-to-digital converter 402 saturation circuit 403 filter 404 digital-to-analog converter

Claims (3)

[Claims] A saturating means for performing saturation processing on an input digital signal and outputting the same as a saturation signal; an integration means for integrating the saturation signal in accordance with an alternating state of the saturation signal; An effect adding device comprising: a filter unit for filtering a signal as an integration result. 2. The system according to claim 1, wherein said integrator gradually assembles the integrated value to a value of said saturation signal in a time sufficiently shorter than one cycle time of said saturation signal when the polarity of said saturation signal is inverted. The effect adding device according to the above. 3. The method according to claim 1, wherein the integrating means gradually approximates the integrated value to a value of 0 in a time sufficiently shorter than one cycle time of the saturation signal when the polarity of the saturation signal is inverted. Effect adding device.