JP3504387B2 - Electronic musical instrument - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic musical instrument, and more particularly to an electronic musical instrument capable of controlling a complicated envelope with a simple structure.

[0002]

2. Description of the Related Art Conventionally, in an electronic musical instrument, waveform data is stored in a waveform memory, the waveform data is read out at an address interval corresponding to the pitch of a key depression, and the envelope signal is multiplied to generate a tone signal. There was a method of generating electronic musical instruments. In the electronic musical instrument of such a system, the amplitude of the original waveform data obtained by PCM recording the original sound is processed into a certain level, corrected and stored, and the envelope of the musical tone signal output is entirely from the attack to the release by the envelope signal. Was configured to take control.

[0003]

In the conventional electronic musical instrument as described above, since envelope control is performed entirely by the envelope signal, it is necessary to faithfully generate envelope waveforms of a plurality of phases from attack to release. However, as the number of phases increases, the number of parameters and the phase shift processing load of the control device increase, and there is a problem that a control device having an increased memory capacity or a large processing capacity is required. In addition, since the waveform data stored in the waveform memory is processed so that the original sound data has a constant amplitude, the tone color changes particularly in the attack portion, and there is a problem that a tone signal faithful to the original sound cannot be generated. there were. An object of the present invention is to improve the above-mentioned problems of the prior art and to provide an electronic musical instrument capable of controlling an arbitrary envelope with a simple configuration and generating a tone signal faithful to an original sound. To provide.

[0004]

SUMMARY OF THE INVENTION The present invention is an electronic musical instrument for generating a musical tone signal by adding an envelope to a waveform signal generated by a waveform signal generating means based on an envelope signal generated by an envelope signal generating means. The envelope signal generating means can set an arbitrary envelope signal initial value. Also,
The waveform signal generated from the waveform signal means is provided with at least an envelope in the attack phase.

[0005]

In the electronic musical instrument of the present invention, since the envelope signal generating means can set an arbitrary envelope signal initial value, for example, when the attack is started from a predetermined level,
By generating a waveform with a small change in the envelope level, it is possible to reproduce the tone signal waveform stored in the waveform memory as it is. Further, if the waveform signal generated from the waveform signal means is provided with an envelope in the attack phase, it is not necessary to perform envelope control during the attack, the number of parameters is reduced, the memory capacity is reduced, and the phase transition is performed. The number of times parameter setting processing is performed is reduced, and the processing load on the control device is reduced. Furthermore, it is possible to generate a waveform faithful to the tone color and envelope of the original sound.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration of an electronic musical instrument to which the present invention is applied. CPU1 is ROM2
It is a central processing unit that controls the entire electronic musical instrument based on a control program stored in. In addition to programs, the ROM 2 also stores tone color parameters, frequency information tables, and the like. The tone color parameters include the waveform address in the waveform ROM, the sampling rate, the amplitude envelope parameter, and the like. The RAM 3 is used as a work area and a buffer and also stores the panel state and the like. Further, the battery may be backed up. The keyboard circuit 4 includes, for example, a plurality of keys each having two switches, a scanning circuit that scans the switches to capture state information, a circuit that detects a key-on or key-off event from a change in the state of the key, and the strength of key depression. It is composed of a touch detection circuit for detecting. The panel circuit 5 is composed of various switches for tone color selection, effect selection, volume setting, etc., and a display device for displaying characters and figures by liquid crystal or LEDs.

The amplitude envelope generating circuit 6 is configured as described later and generates an envelope signal Ec of an arbitrary shape for each tone generating channel based on the envelope parameter set by the CPU 1. The waveform address generation circuit 7 is based on the read start address, frequency information (address interval information corresponding to pitch), and loop address information set by the CPU 1, and an address range corresponding to a desired tone color for each tone generation channel. At the inner,
In addition, a waveform read address that sequentially advances at address intervals corresponding to the tone pitch of the key depression is generated. Then, the integer part of the read address is sequentially output to the waveform ROM 8, and the decimal part is output to the sample interpolation circuit 9. Waveform data, which will be described later, is stored in the waveform ROM 8 for each tone color, and the waveform data is read according to the read address from the waveform address generation circuit and input to the sample interpolation circuit 9.

The sample interpolation circuit 9 stores a plurality of waveform data read from the waveform ROM 8 for each tone generation channel, and based on the fractional part data of the waveform address output from the waveform address generation circuit 7. Interpolation calculation is performed, and the interpolated tone waveform amplitude value is output. Multiplier 10
Is a tone waveform amplitude value multiplied by the envelope signal Ec,
The accumulator circuit 11 adds and synthesizes all the musical tone signals of a plurality of musical tone generating channels that are time-divisionally processed for each sampling period. The D / A converter 12 converts a digital musical tone signal into an analog signal, and is sounded by a sound system 13 including, for example, an amplifier and a speaker. If necessary, a floppy disk drive circuit, a memory card interface circuit, and a MIDI interface circuit may be provided.

FIG. 2 is a block diagram showing the configuration of the amplitude envelope generating circuit 6. The interface circuit 20 exchanges data with the CPU 1 via the bus. The time variable signal generation circuit 21 generates a signal α that exponentially decreases from 1 for each phase by a configuration described below based on the parameter τ set by the CPU 1. The phase transition control circuit 22 detects the end of each phase based on the signal α and generates the signal trm by the configuration described later. Amplitude level reproduction circuit 23
Generates an envelope signal Ec based on α and the target level of each phase, etc., by the configuration described later.

FIG. 3 is a block diagram showing the configurations of the time variable signal generation circuit 21 and the phase transition control circuit 22. When the key is turned on, the signal W
f becomes 1, and the signal trm is forced to be 1. Then, 1 is output from the selector 30 and the α register 31
Written in. Further, τ1 which is the speed parameter previously written from the CPU 1 into the τB register is τ
It is transferred to the W register. The CPU 1 then sets the speed parameter τ2 of phase 2 in the τB register. The multiplier 32 and the subtractor 33 have α _t =
(1- [tau]) [ alpha] _t-1 is performed, the output is written again in the [alpha] register, and [alpha] decreases exponentially.

The comparator 37 compares α with the output of the selector 38, and outputs 1 when α is smaller. From the selector 38, according to a parameter ZW described later, a constant K
Alternatively, the parameter LW set by the CPU 1 is output. The constant K is usually a small value, for example, 0.1 or less, and when ZW is 0, the signal t is reduced when α becomes K or less.
rm occurs and the phase transitions. The RQ register 44 is for requesting the CPU 1 to transfer a new parameter (set τ3 to the τB register) with the phase transition, and is cleared by the signal Clf controlled by the CPU 1. 3 and 4
There are actually sounding channels for each register in.

FIG. 4 is a block diagram showing the configuration of the amplitude level reproducing circuit 23. The Ei register 52 is a register for storing an initial value in each phase. At the start of sound generation, the signal W becomes 1 and the envelope initial value Es is set in the Ei register under the control of the CPU 1. Further, the signal trm causes the parameters L1 and Z1 previously written in the LB register 56 and the ZB register 60 from the CPU 1 to be transferred to the LW register 58 and the ZW register 62. The CPU 1 then sets the parameters L2 and Z2 of phase 2 in the LB register 56 and the ZB register 60. When the Z parameter is 0, the L parameter is output from the selector 59 and used as the target level value for each phase.

The subtractor 53, the multiplier 54, and the adder 55 perform the following equation, Ec = (Ei-LW) * α + LW, and output the current envelope value Ec. Ec is equal to Ei when α is 1, and gradually approaches the target value LW as α decreases. When the phase transition signal trm is generated, the current envelope value Ec is written in the Ei register via the selectors 50 and 51.

When the Z parameter is 1, the selector 5
0 is output from 9 as the target value. Then, the parameter LW is input to the comparator 37 via the selector 38 of FIG. 3 and acts as a parameter for controlling the arrival rate. For example, if Z is set to 1 and LW is set to 0.5 and the speed parameter is set to be long, a phase transition occurs when α decreases from 1 to 0.5 in a shape close to a straight line. By adopting such a configuration, the initial value is 0 with simple hardware and a small amount of parameters.
An envelope of any shape can be generated including envelopes other than.

FIG. 5 is an explanatory diagram showing an example of envelope parameter data preset and stored for each timbre. The envelope parameter consists of 6-word (6-byte) data as shown in the figure, and has an initial level E
s, speed τ for two phases, level L and Z parameters, speed parameter τ3 for release phase
Is remembered. In addition to the tone color, the parameter may be stored for each tone range or touch, or the parameter may be modified according to the tone range or touch information and used.

FIG. 6 is a waveform diagram showing an example of the signal waveform of each part of the amplitude envelope generating circuit 6. When the key is pressed at time t0, the keyboard circuit 4 detects the change and notifies the CPU 1 of the change. When the CPU 1 receives the key-on information, it selects a vacant tone signal generation channel, sets various parameters required for sound generation in the waveform address generation circuit 7 and the amplitude envelope generation circuit 6, and starts the sound generation operation. In this example, it is assumed that only the Z parameter in the first phase is 1.

The signal α becomes 1 when the key is turned on, and decreases at a speed corresponding to the speed parameter τ1 of the first phase. Then, at time t2, when α decreases to less than L1, the phase transition signal trm is generated and the phase shifts to the second phase. Here, α is set to 1 again, and this time decreases at a speed corresponding to the speed parameter τ2 of the second phase. When the key-off occurs at time t3, the phase transition signal trm is forcibly generated by the control of the CPU 1 and the phase shifts to the release phase.

Since the Z parameter is 1 in the first phase, the envelope current value Ec is the initial value Es.
From the target value to 0. In the second phase, the Z parameter is 0, so the Z value decreases from the envelope value at the end point t2 of the first phase toward the target value L2 (normally L2 is also 0). Therefore,
The current envelope value Ec changes as shown in FIG. 6 in response to the change of α.

The waveform ROM 8 stores waveform data having an envelope shape as shown in FIG. 6, for example. This waveform data is stored as it is without processing the amplitude envelope of the original sound during the period from time t0 to t1 which is the attack period of the original sound, and the signal is processed so that the amplitude envelope becomes a constant level after the attack period. It was done. Such waveform data and envelope signal E
A tone signal is generated by multiplying with c. Therefore, the envelope shape of the output musical tone signal has a shape as shown in the lowermost part of FIG. 6, the tone and envelope of the attack portion are reproduced almost faithfully to the original sound, and the four phases from attack to release are set with few parameters. The envelope of can be added.

Although the embodiment has been described above, the following modifications are also possible. Regarding the form of the envelope generating circuit, the envelope generating circuit based on the normalized time variable signal α is disclosed. For example, the envelope current value is always stored and updated, and the difference between the target value and the current value is multiplied by the speed parameter. The present invention can be similarly applied to an envelope generating circuit of a type in which one is added to the current value. The method of setting the envelope initial value in the circuit of the embodiment is arbitrary, and for example, the initial value Es is set in the LW register and α is forcibly reset to 0 to generate the phase transition signal trm.
Es may be transferred to the Ei register via the path of the selector 59, the adder 55, and the selectors 50 and 51. In this way, the selector 51 and the transfer circuit of Es are unnecessary.
Further, since α becomes 0 when the speed parameter τ is set to 1, it is possible to transfer Es by controlling τ.

The range to which the envelope information is given may be the attack phase (up to the maximum envelope of the original sound) or may be shorter than that. In the case of a synthetic sound, a process of adding an attack phase envelope is necessary, but in the case of a natural sound, the attack portion of the PCM-recorded data may be used as it is without being processed. In the embodiment, the transition timing of the first phase is at the end of the first decay, but the transition timing of the first phase is the same as the end timing of the attack phase, and the envelope control of the attack phase is performed in the first phase. May be.

If all the target levels for the transition of the decay phase of each timbre are 0, the Z parameter in the embodiment is omitted, L1 is used exclusively for controlling the reaching rate (end value of α), and L2 is deleted. You may. If you do this,
The number of parameters is further reduced, and the structure of the envelope signal generating circuit is also simplified.

[0023]

As described above, in the electronic musical instrument of the present invention, since the envelope signal generating means can set an arbitrary initial value of the envelope signal, for example, the attack starts from a predetermined level and the envelope level changes. By generating a waveform having a small number of waveforms, it is possible to reproduce the tone signal waveform stored in the waveform memory as it is. Further, if the waveform signal generated from the waveform signal means is provided with an envelope in the attack phase, it is not necessary to perform envelope control during the attack, the number of parameters is reduced, the memory capacity is reduced, and the parameter setting is performed. This has the effect of reducing the number of times of processing and reducing the processing load on the control device. Further, there is an effect that a waveform faithful to the tone color and envelope of the original sound can be generated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an electronic musical instrument of the present invention.

FIG. 2 is a block diagram showing a configuration of an amplitude envelope generating circuit 6.

FIG. 3 is a block diagram showing configurations of a time variable signal generation circuit 21 and a phase transition control circuit 22.

FIG. 4 is a block diagram showing a configuration of an amplitude level reproducing circuit 23.

FIG. 5 is an explanatory diagram showing an example of data of envelope parameters.

FIG. 6 is a waveform diagram showing an example of signal waveforms of respective parts of the amplitude envelope generating circuit 6.

[Explanation of symbols]

1 ... CPU, 2 ... ROM, 3 ... RAM, 4 ... Keyboard circuit,
5 ... Panel circuit, 6 ... Amplitude envelope generating circuit, 7 ...
Waveform address generation circuit, 8 ... Waveform ROM, 9 ... Sample interpolation circuit, 10 ... Multiplier, 11 ... Accumulation circuit, 12 ... D /
A converter, 13 ... Sound system

Claims (2)

(57) [Claims] 1. An envelope signal comprising a plurality of phases.
To generate the signal and a wave with the amplitude envelope of the original sound added during the attack period.
Means for generating shape data and an amplitude envelope of the original sound is added during the attack period.
Waveform data multiplied by the envelope signal
Generating the envelope signal, the means for generating the envelope signal having at least one phase including a first phase after key depression.
Envelope velocity, envelope of the first phase
Initial value and release phase envelope after key release
Parameter storing means for storing the tone velocity for each tone color, and the envelope initial of each phase other than the first phase.
The value is the envelope at the end of the immediately preceding phase.
And a means for setting a threshold value, and the initial envelope value of the first phase is the attack period.
Between the musical tone signals according to the envelope of the waveform data
An electronic musical instrument characterized by being set to a value at which is generated . 2. The parameter storage means stores the envelope velocity of the first phase after key depression, the first velocity.
Phase envelope initial value
Belope target value, second phase following the first phase
Envelope velocity, envelope of the second phase
Target value and release phase envelope after key release
The speed of each tone is stored for each tone color.
Electronic musical instrument according to 1.