JPS623830Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an envelope generator for an electronic musical instrument that can obtain envelope waveforms that vary depending on pitch.

A device shown in FIG. 1 is known as a simple electronic musical instrument that generates a common envelope waveform for each key. In Fig. 1, -V is a negative voltage source, and the key opener _K1 ... _Ko corresponding to the key is closed at the same time as the key is pressed, and the negative pulse generated at that time is formed by the capacitor C and the resistor R. is differentiated in a differentiating circuit. Then, one monostable multivibrator MSM common to each lock switch is driven. The output pulse of the monostable multivibrator MSM is input to the envelope waveform generation circuit EVP to obtain a predetermined envelope waveform, which is then input to the amplitude modulation circuit MOD.
, amplitude modulates the signal from the musical tone. IN is a musical tone input terminal, OUT is a musical tone output terminal, and the waveforms shown next to each block are typical signal waveforms. In Figure 1, the circuits from the monostable multivibrator MSM to the amplitude modulation circuit MOD are all common regardless of the pitch, so a musical tone with the same envelope waveform for each pitch is obtained, which is extremely monotonous. Ta.

On the other hand, the piano, which is a natural musical instrument, emits musical tones with different envelope waveforms depending on the key, that is, the pitch.

An object of the present invention is to improve the above-mentioned drawbacks of electronic musical instruments and to provide an envelope generator for electronic musical instruments that can generate different envelope waveforms for different pitches with a relatively simple configuration.

Embodiments of the present invention shown in the drawings will be described below. Fig. 2 is a configuration diagram showing an embodiment of the present invention corresponding to Fig. 1, in which the capacitors of the differential circuits related to the key openers K ₁ ,...K _o are shown as C ₁ ...C _o and have different values. For example, the capacity may be selected to be large for bass sounds, and the capacity to be small for high sounds. FIG. 3 is a waveform diagram of each part of FIG. 2, with circle symbols corresponding to each other, and the upper row shows waveforms for high-pitched sounds, and the lower row shows waveforms for low-pitched sounds. In Figure 2, if the capacitances of the capacitors _C1 ... _Co are selected as described above, the waveforms differentiated at the points will have sharp waveforms and relatively blunt waveforms for both high and low sounds, as shown in Figure 3. It will be done. Next, we will introduce a circuit with different attack and decay times for envelope waveforms.
Since AD1 and AD2 are connected in parallel, it is applied to that circuit. One circuit AD1 is a waveform inverter
Formed by INV and differential circuit DIF, the other circuit
AD2 is formed by an amplifier IVA and a waveform converter MD. The amplifier IVA has the characteristic of inverting the waveform and obtaining a saturated output at a value approximately in the middle of the differential wave output, and the waveform converter MD receives the saturated output of the amplifier IVA, charges a capacitor, and takes out the output that discharges it. A waveform as shown in FIG. 3 is obtained. Therefore, in the case of high-pitched sounds, the waveform shown in Fig. 3 is a blunted form of the sharp differential waveform signal (Fig. 3), and in the case of low-pitched sounds, the waveform shown in Fig. 3 is a blunted waveform (Fig. 3), but the waveform shown in Fig. 3 is a broad signal (Fig. ) is obtained, resulting in a further dulled figure 3. In Figure 3, Td is said to be the decay time. In FIG. 3, since a sharp waveform is obtained, the attack time Ta is almost zero. Therefore, it can be seen that the waveforms shown in FIG. 3 after passing through AD1 and AD2 have different attack times and decay times. Next, the signals shown in FIG. 3 are combined and applied to the voltage-controlled amplifier VCA as shown in FIG. The musical tone from the musical tone signal input terminal IN is amplitude-modulated according to the waveform of , and a musical sound waveform as shown in FIG. 3 is obtained. Therefore, as shown in FIG. 3, a low-pitched musical tone with an envelope waveform that leaves a lingering reverberation compared to high-pitched tones is obtained, resulting in a musical tone similar to that of a piano, a natural musical instrument.

Next, FIG. 4 is a circuit diagram specifically showing AD1 and AD2 in FIG. 2. The circuit AD2 has two transistors connected in series, and a resistor Rc and a capacitor Cc are charged and discharged when the waveform signal shown in FIG. 2 is applied, and the time constant thereof is selected to be relatively large. On the other hand, in circuit AD1, the differential circuit
Because DIF operates, there is no attack time. Note that the output terminals in FIG. 4 indicate the terminals in FIG. 2.

The case where the capacitors C _{1 .}

For example, the same capacitor is used for each octave.

Further, the circuit for obtaining the envelope waveform according to the pitch may be divided into two series of circuits, or may be composed of only one series of circuits. Furthermore, when two or more keys are pressed in succession, it is preferable to use a priority circuit and make only the lowest note valid.

In this way, according to the present invention, even with a relatively simple configuration, different envelope waveforms can be obtained depending on the position of the pressed key, so musical tones have a lingering sound in the low tones like a natural instrument, and decay quickly in the high tones, so An electronic musical instrument that eliminates the monotony of conventional instruments has been obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional envelope generator for an electronic musical instrument, FIG. 2 is a diagram showing the configuration of an embodiment of the present invention, FIG. 3 is an operation waveform diagram of FIG. 2, and FIG. It is a specific circuit diagram of the circuit inside. K ₁ ...K _o ...Key opener, C, C ₁ ...C _o , Cc...
Capacitor, R, Rc... Resistor, MSM... Monostable multivibrator, EVP... Envelope waveform generation circuit, MOD... Amplitude modulation circuit, INV...
Waveform inverter, DIF...differentiator circuit, IVA...amplifier, MD...waveform converter, VCA...voltage controlled amplifier.

Claims (1)

[Claims for Utility Model Registration] 1. Capacitive elements of different values are connected to the lock mechanism so as to obtain different pulse widths for each key, and the output pulse from the lock mechanism is controlled by the attack time and decay time. 1. An envelope generator for an electronic musical instrument, characterized in that time is supplied in parallel to different circuits, and the outputs of both circuits are mixed to obtain an envelope waveform. 2. The electronic musical instrument according to claim 1, wherein the circuit for obtaining the envelope waveform according to the pitch is configured by connecting circuits with different attack times and decay times in parallel. Envelope generator.