JPH05216474A - Effect addition device - Google Patents

Abstract

PURPOSE:To obtain desired distortion effect with simple circuit constitution. CONSTITUTION:In LFO mode, MS=0 and a selector 5 selects the count output of a counter 6. The count direction is inverted with a constant period by a change of a clock phi1. Sine waveforms having 0-1/4 and 1/4-1/2 cycles are read out of a ROM 7 alternately with the count output. The sine waveforms having 0-1/2 cycles are converted into sine waveforms having 1/2-1 cycles by an inverting circuit 8 and a half-adder 9 and selected alternately by a selector 10 and read out to read the sine waveform having one cycle in order. In distortion mode, the selector 5 supplies the amplitude absolute value of the waveform signal to the ROM 7, a corresponding waveform value is outputted and supplied to a selector 10 while having a waveform value which is shifted by a 1/2 cycle, and one waveform value is selected and outputted according to the state of the MSB of an input waveform signal.

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 for adding an effect to a musical sound.

[0002]

2. Description of the Related Art Conventionally, there has been known an effect adding apparatus which distorts a musical sound waveform through a clipper circuit in order to add an effect to a musical sound, particularly to add a distortion effect which distorts the musical sound. FIG. 12 is a circuit configuration diagram for explaining a conventional effect adding device, in which a musical tone signal waveform is supplied to a clipper circuit 1 and an output of the clipper circuit 1 is taken out through a low pass filter 2. Here, the characteristic of the input voltage to the output voltage of the clipper circuit 1 is as shown in FIG. 13, and the circuit is usually composed of a diode. Then, the upper and lower amplitude value portions of the input voltage are clipped so that a voltage above a certain fixed value and a voltage below a certain fixed value are not output. Then, the musical tone signal obtained as the output signal is distorted from the musical tone signal which is the input signal, and contains more harmonic components. Here, the low-pass filter 2 performs an operation for cutting unnecessary harmonic components, and as a result, according to the conventional effect adding device, a distorted musical tone signal having an input voltage-output voltage characteristic as shown in FIG. Will be obtained as the output.

[0003]

However, in such a conventional effect adding device, the clipper circuit and the low-pass filter need to be provided exclusively for adding the distortion effect, and when mounted on a musical instrument or the like. There is a problem that a mounting space is required and a cost is increased.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention reduces the dedicated circuit configuration, has a simple circuit configuration, does not require a mounting space, is low in cost, and adds a desired effect to a musical tone. It is an object of the present invention to provide a possible effect addition device.

[0005]

SUMMARY OF THE INVENTION One-cycle trigonometric function waveform data is generated based on the waveform data from a storage means that stores one-quarter cycle waveform data of the trigonometric function, or an absolute-valued musical tone is stored in this storage means. The point is that it is possible to specify whether to input the amplitude value of the signal and perform an operation on the output based on the waveform data of 1/4 cycle to obtain a musical tone with a distortion effect added.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

<Structure> FIG. 1 is a diagram showing the entire structure of the effect adding device.
The digital musical tone waveform information in 2's complement format obtained by digital conversion is temporarily stored in memory and latched.
The output of the latch circuit 3 is all converted into a positive data value by the absolute value circuit 4 and supplied to the B input terminal of the selector 5. The counter 6 is an up / down counter and is for creating an address signal when reading the memory contents of the ROM 7 which is the storage means. The clock pulse φ ₁ (FIG. 2) given to the S terminal of the counter 6 is used. Switching between up-counting and down-counting according to the reference), and the output signal of the counter 6 is given to the A terminal of the selector 5 as the address signal. In addition, S of the selector 5
Mode select signal MS that takes a value of 0 or 1 at the terminal
The mode selection signal MS is provided with, for example, a mode selection switch (shown in the figure) for selectively selecting two types of effect modes for distortion and vibrato tones provided on the operation panel surface of the effect addition device. Control signal obtained from (No). For example, when MS = “0” in the mode select signal MS, the selector 5 selectively outputs the input from the A terminal, that is, the output signal from the counter 6 to the X terminal, and when MS = “1”, the selector 5 outputs the B signal. Input from the terminal, that is, digital tone waveform information that has passed through the absolute value circuit 4, is selectively output to the X terminal and both are supplied to the A terminal of the ROM 7 as an address signal.

Here, it is assumed that the ROM 7 stores data having address (time) characteristics as shown in FIG. 3, that is, waveform data of at least 1/4 cycle of a sine wave, and the data is the D terminal. Is output as data output. The data output read from the ROM 7 is input to the inverting circuit 8, and "1" and "0" of all bits thereof are inverted. The data output from the inverting circuit 8 is input to the half adder circuit 9, and 1 is added to the data input to select 1
Add to B terminal of 0. That is, in the inverting circuit 8 and the half adder circuit 9, the negative number of the data output of the ROM 7 is converted into a two's complement representation, and by this conversion, the data format of the digital musical tone waveform information (two's complement format) described above. ). The data output of the ROM 7 is supplied to the A terminal of the selector 10 as it is. When the control signal described later applied to the S terminal of the selector 10 is “0”, the data output from the A terminal is selectively output from the X terminal. Conversely, when the control signal is "1", the data output converted as described above from the B terminal is selectively output from the X terminal, and both are output from the terminal OUT which outputs the final output of this effect adding device.

Further, the AND gate 11 has a clock pulse φ ₂ having a cycle twice that of the clock pulse φ ₁ described above.
(See FIG. 2) and the mode select signal MS described above that has passed through the inverter 12. Further, the AND gate 13 has the most significant bit data MSB of the digital tone waveform information that has passed through the latch circuit 3 and the mode select signal MS.
Is added directly. And AND gate 1
1 and the output signal of the AND gate 13 are both OR gate 1
4 and the output of the OR gate 14 is applied to the S terminal of the selector 10 as a control signal. Here, when the mode select signal MS is MS = “0”, the clock pulse φ ₂ is output from the OR gate 14, and MS = “1”.
If, the most significant bit data M of the digital tone waveform information is
SB is output from the OR gate 14 and applied to the S terminal of the selector 10 as a control signal.

<Operation> The operation of the embodiment having the above-mentioned configuration will be described. The effect adding device according to this embodiment basically has two types of functions. When the mode select signal MS is MS = “0”, the low frequency oscillator (LF) for adding the vibrato (frequency modulation) effect is used.
O) mode is entered, and when MS = “1”, the distortion mode for adding the distortion effect is switched and selected.

Low-frequency oscillator mode When the mode selection signal MS is MS = "0", the selector 5 selectively outputs the output signal from the counter 6, so that the counter 6 which operates up and down based on the clock pulse φ ₁ outputs the signal. The output signal of becomes the address signal for reading the stored contents of the ROM 7. Also, this MS =
If "0", since it is applied to the selector 10 are output clock pulses phi ₂ from the OR gate 14 is at the same time, the selector 10 of the clock pulse phi ₂ "0",
According to "1", the input from the A terminal and the input from the B terminal, that is, the direct data output read from the ROM 7 and the data output obtained by inverting the data output from the ROM 7 to the negative side are alternately selected and output. That is (φ ₂ ,
When φ ₁ ) = (0, 0), the counter 6 operates as an up-counter, so the memory contents of the ROM 7 are read in the order of addresses, and the selector 10 selectively outputs the direct data output from the ROM 7. The final output from the terminal OUT of this effect adding device exhibits output characteristics as shown in FIG. When (φ ₂ , φ ₁ ) = (0, 1), the counter 6 operates as a down counter, so the memory contents of the ROM 7 are read in the reverse order of the address, and the selector 10 receives the input from the A terminal. Since it is selected, the output of the terminal OUT has the characteristics shown in FIG.
Further, when (φ ₂ , φ ₁ ) = (1, 0), the counter 6
Operates as an up counter, and the selector 10 selectively outputs the input from the B terminal, so that the output signal having the characteristic shown in FIG. 5 is obtained from the terminal OUT. Furthermore,
When (φ ₂ , φ ₁ ) = (1, 1), the counter 6 operates as a down counter, and the selector 10 selectively outputs the input from the B terminal.
An output signal having the characteristics shown in is obtained. Here, the clock pulses φ ₂ and φ ₁ are both cyclically the value “0”,
Since it takes "1", the output signal from the terminal OUT exhibits the characteristics as shown in FIG. 7, and as a result, the effect adding apparatus outputs the waveform data of the sine wave for adding the vibrato effect to the musical sound. Output low frequency oscillator (LFO)
Will have the function as. And this terminal OU
By multiplying the output signal from T (waveform data of one cycle of sine wave) with the digital musical tone waveform information that has passed through the latch circuit 3, the vibrato effect is added to the musical tone.

Distortion mode When the mode select signal MS is conversely MS = "1",
Since the selector 5 selectively outputs the digital musical tone waveform information that has passed through the absolute value circuit 4 or the data obtained by converting the upper several bits into an absolute value, the output signal from the absolute value circuit 4 is the address signal for reading the data from the ROM 7. Becomes When MS = "1", the OR gate 14 simultaneously outputs the most significant bit data MSB of the digital tone waveform information latched by the latch circuit 3. Here, when the most significant bit data MSB = “0”, that is, when the digital tone waveform information which is the tone input data has a positive value, the data output read from the ROM 7 is directly output from the terminal OUT, The characteristics for the address (time) are as shown in FIG. When the most significant bit data MSB = “1”, that is, when the digital tone waveform information has a negative value, the inverting circuit 8 outputs R
The data output read from the OM7 is output by inverting the data output to the negative side, and its characteristics are as shown in FIG. But,
Since the address using the upper several bits of the digital musical tone waveform data here is made into an absolute value by the absolute value circuit 4, the digital musical tone waveform information which is the musical tone input data to this effect adding device is shown in FIG. Output characteristics as shown in 10 are obtained. Then, when the value of the digital tone waveform information changes between positive and negative, for that input data, output data showing the input voltage-output voltage characteristic as shown in FIG. 11 is finally obtained from the terminal OUT, and therefore the original data is obtained. The operation having the distortion function of distorting the musical sound input waveform is performed.

That is, in the above embodiment, the low frequency generation for obtaining the waveform data of one cycle of the sine wave from the waveform data of the quarter wave of the sine wave stored in the ROM 7 in response to the mode switching control by the mode select signal MS. RO mode as an address signal
By accessing the 1/4 cycle waveform data of the same sine wave stored in M7, and obtaining the 1/2 cycle waveform data,
Two types of operations, a distortion mode for distorting the input digital musical tone waveform information and a distortion mode, are switched to operate.

As described above, in this embodiment, in the low frequency oscillator mode and the distortion mode, for example, the ROM 7 which is the storage means for storing the sine wave data of at least 1/4 cycle, the inverting circuit 8 and the half adder circuit 9 are provided. Is not a dedicated circuit for each, but is shared. Therefore, a digital circuit such as a ROM for a low-frequency oscillator, which is provided to obtain a vibrato effect on a musical tone signal, can also be used to obtain a distortion effect on a musical tone signal, and the distortion effect can be added with a simple configuration. It can be done. By providing a mode switching means such as a mode switching switch, it is possible to switch and select two types of functions: an oscillator for adding the distortion effect and an oscillator for the vibrato effect.

[0015]

As described above, according to the present invention,
It functions as a low-frequency oscillator for adding a vibrato effect (frequency modulation effect) to a musical tone waveform, and adds a distortion effect (effect that distorts a musical tone) to a musical tone waveform without providing a dedicated circuit configuration. Therefore, there is an effect that the effect addition device having a low cost can be obtained with a simple configuration without requiring a mounting space for externally attaching a diode as in the conventional case.

[Brief description of drawings]

FIG. 1 is an overall circuit configuration diagram for explaining an effect adding device according to an embodiment of the present invention.

FIG. ₂ is a diagram showing clock pulses φ ₁ and φ ₂ .

FIG. 3 shows waveform data of a quarter cycle of a sine wave stored in a ROM 7 and a terminal O in a low frequency oscillator mode.
The figure which shows the output waveform data output to UT.

FIG. 4 is a diagram showing output waveform data output to a terminal OUT corresponding to clock pulses φ ₁ and φ ₂ in the low frequency oscillator mode.

FIG. 5 is a diagram showing output waveform data output to the terminal OUT corresponding to clock pulses φ ₁ and φ ₂ in the low frequency oscillator mode.

FIG. 6 is a diagram showing output waveform data output to the terminal OUT corresponding to clock pulses φ ₁ and φ ₂ in the low frequency oscillator mode.

FIG. 7 is a diagram showing a waveform of one cycle of a sine wave obtained by the effect adding device in the low frequency oscillator mode.

FIG. 8 is a characteristic diagram of musical tone waveform data distorted by the effect adding device in the distortion mode.

FIG. 9 is a characteristic diagram of musical tone waveform data distorted by the effect adding device in the distortion mode.

FIG. 10 is a characteristic diagram of musical tone waveform data distorted by the effect adding device in the distortion mode.

FIG. 11 is a characteristic diagram of musical tone waveform data distorted by the effect adding device in the distortion mode.

FIG. 12 is a circuit configuration diagram for explaining a conventional effect adding device.

13 is an input / output characteristic diagram of the clipper circuit 1 in FIG.

14 is an input / output characteristic diagram of the effect addition device of FIG.

[Explanation of symbols]

 3 Latch circuit 4 Absolute value circuit 5, 10 Selector 6 Counter 7 ROM 8 Inversion circuit 9 Half addition circuit

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Claims (1)

[Claims] 1. Inputting: storage means for storing waveform data of a trigonometric function of 1/4 cycle; and readout means for outputting a readout signal for alternately reading out waveform data from the storage means in forward and reverse directions. Detecting means for detecting the absolute value of the amplitude of the signal; and first selecting means for selecting one of the amplitude value from the detecting means and the read signal from the reading means and supplying it to the storage means, Conversion means for converting the waveform data read from the storage means into waveform data having a half-cycle phase shift, and the waveform data from the conversion means and the storage means are input, and the reading means is performed by the first selection means. When the read signal from is selected, the waveform data from the conversion means and the storage means are alternately selected and output, and the amplitude value from the detection means is selected. Rutoki the effect adding apparatus having a, a second selection means for selectively outputting any one of the waveform data in accordance with the amplitude value of the input signal.