JPS5857754B2 - Touch response device for electronic musical instruments - Google Patents

Description

[Detailed description of the invention] The present invention relates to a touch response device for an electronic musical instrument.

The touch response device of an electronic musical instrument is a device installed to generate expressive musical tones.It obtains a signal according to the initial key touch (for example, the speed at which the key is pressed), and uses this signal to adjust the pitch, timbre, and volume. This is a device designed to control the following.

Here, in digital electronic musical instruments, it is necessary to extract the signal corresponding to the touch as a digital signal.
The conventional method for this purpose was to obtain a voltage corresponding to the touch and pass it through an analog-to-digital converter (which internally includes a digital-to-analog converter) to obtain a digital signal. .

However, analog-to-digital converters (digital-
Analog converters) usually require a multi-stage resistor ladder circuit, which has the disadvantage of increasing costs.

This invention has been made in view of the above points, and is a touch response of a digital electronic musical instrument that is designed to reduce costs by obtaining a digital signal corresponding to an initial key touch without using a resistor ladder circuit. The aim is to provide equipment.

According to this invention, a key press signal indicating that a key is being pressed rises in response to the key press, and this key press signal is delayed by a time corresponding to the initial key touch by the variable delay means, By combining this delayed key press signal with the key press signal km before being delayed, a pulse having a pulse width corresponding to the touch is obtained.

Then, by measuring this pulse width with a timer, a digital signal corresponding to the touch is obtained.

The present invention will be described in detail below based on an embodiment of the accompanying drawings.

In FIG. 1, a key switch circuit 1 is a circuit having switches corresponding to each weight of an electronic musical instrument, and generates a key code KC corresponding to a pressed key and leads it to a musical tone forming circuit 2.

The musical tone forming circuit 2 includes a sound source waveform memory, a memory readout control circuit, an envelope signal generator, a multiplier, etc. (not shown).
A circuit having the above reads out the acoustic waveform memory at a speed corresponding to the key code KC to obtain a sound source signal of a pitch corresponding to the pressed key.

This sound source output signal is multiplied by an envelope signal from an envelope signal generator, an envelope is applied, a musical tone is formed digitally, and a musical tone is formed analogously via a digital-to-analog converter, and then output.

The musical tone-formed signal then reaches the sound system 3 and is generated.

The touch detector 4 detects the degree of key touch (in this embodiment, the speed of touch).

In the touch detection section 4, the key press signal generation circuit 5 causes a key press signal P indicating that the key is being pressed to rise in response to the key press, and guides it to the variable delay circuit 6.

The variable delay circuit 6 receives information on the key touch speed from the key switch circuit 1, and outputs the key press signal P with a delay corresponding to the speed.

The pulse forming circuit 7 inputs the delayed key press signal y from the variable delay circuit 6 and the pre-delayed key press signal P from the key press signal generating circuit 5, and logically synthesizes the two.

Therefore, the pulse forming circuit I outputs a pulse whose pulse width corresponds to the key touch speed.

The output of the pulse forming circuit 7 is applied to a timer circuit 8, and its pulse width is measured.

The measured value of the timer circuit 8 is input to the musical tone forming circuit 2, and changes the set waveform of an envelope generator, for example.

In this way, the sound system 3 generates musical tones depending on the key touch speed.

The touch detection section 4 is configured as shown in FIG. 2, for example.

In FIG. 2, the key press signal generation circuit 5 includes one switch S.
It is composed of W.

This switch SW is a switch that changes depending on the key press, and is conductive when the key is released and non-conductive when the key is pressed.

Further, the input side of this switch SW is grounded, and the signals 11 and 11 are applied to the output side.

Therefore, the output P of the key press signal generating circuit 5 rises to +1111 while the key is being pressed, as shown in FIG.

The variable delay circuit 6 includes an integrating circuit made up of a combination of a fixed resistor R1 and a variable resistor R2 connected in parallel, and a capacitor C.

Therefore, when a key is pressed and the key press signal P is output, the voltage of the capacitor C rises gently as shown in FIG.

The variable resistor R2 is a photosensitive resistor whose resistance value changes when irradiated with light, and light is irradiated from the lamp 10 provided near the variable resistor through the slit S1.

Here, the slit Sl is linked to the key press, and is located at a position that blocks the light from the lamp 10 when the key is released, and when the key press starts, moves in the direction of the arrow X to guide the light to the photosensitive resistor R2.
Furthermore, when the key is pressed all the way, it stops again at the position where the light is blocked (the position indicated by the dotted line Sl' in FIG. 2).

Considering this in relation to the switch SW, when the key is released, the switch SW is on and the light from the lamp 10 is blocked, and when the key starts being pressed, the switch SW is turned off and the light from the lamp 10 is transmitted through the photosensitive resistor. Guided to R2.

When the key is pressed all the way, the light from the lamp 10 is shut off again.

In order to perform such an operation, the key must be set to a third key, for example.
A mechanism as shown in the figure may be provided.

In other words, in FIG. 3, there is a slit Sl on the bottom surface of the key 20.
and a contactor 21 is attached.

Here, the tip of the contact 21 turns off the switch SW when the key 20 starts to be pressed.

In addition, when the key is released, the hole of Sl is located above the line connecting the lamp 10 and the photosensitive resistor R2, and the hole of the key 2
When you start pressing the button, the hole will go down and the lamp 10 will appear.
The light is guided to the photosensitive resistor R2.

When the key is pressed all the way, the hole is connected to the lamp 10 and the photosensitive resistor R.
It is located below the line connecting 2 and blocks the light again.

Therefore, the time during which the photosensitive resistor R2 is irradiated with light is:
The faster the key touch speed, the shorter the time.

By the way, the photosensitive resistor R2 has a property that its resistance value decreases when it is irradiated with light.

Therefore, the time constant of the integrating circuit consisting of resistors R1 and R2 and capacitor C is thick when light is blocked (, photosensitive resistor R
When the light is guided to 2, it becomes smaller.

As mentioned above, when the key touch speed is fast, the photosensitive resistor R2
Since the irradiation time becomes shorter, the time during which the time constant is small becomes shorter, and therefore the time until the voltage of the capacitor C becomes saturated becomes longer.

Furthermore, when the key touch speed is slow, the irradiation time of the photosensitive resistor R2 becomes long, so the time period during which the time constant is small becomes long, and therefore the voltage of the capacitor C is saturated in a short time.

Figure 4 shows this situation, where the solid line shows the case where the key touch speed is slow and the dotted line shows the case when the key touch speed is fast.

The voltage on capacitor C is applied to inverter 11.

This inverter 11 uses its threshold voltage to delay the rise of the step signal P in accordance with the key touch speed.

That is, the voltage of capacitor C is 5K as shown in Figure 4.
i, and the threshold voltage of the inverter 11 is at the level shown by the dashed line in the figure.
The output of 1 is as shown in FIG. 4C.

Here, if you press the key with a quick touch, capacitor C
Since the voltage of the inverter 11 changes gradually as shown by the dotted line in FIG. 4, the fall of the output of the inverter 11 is delayed as shown by the dotted line in FIG. The rise of the key signal P is delayed by a time corresponding to the key touch speed).

The pulse forming circuit T is composed of one AND circuit 12,
The variable delay circuit 6 inputs the signal y and the key press signal P from the key press signal generating circuit 5, and the logical product of the two is calculated.

Therefore, the output of the pulse forming circuit I becomes a pulse having a pulse width τ according to the key touch speed as shown in Fig. 4d (if the key touch speed is fast, the pulse width becomes longer as shown by '). ).

In the timer circuit 8, an oscillator 13 generates a high frequency clock pulse CP (FIG. 4e).

The AND circuit 14 makes this clock pulse CP conductive while the output of the pulse forming circuit 7 is at bi level.

Therefore, the AND circuit 14 outputs a number of clock pulses CP corresponding to the key touch speed (Fig. 4 f).
reference).

The counter 15 receives the clock pulse C from the AND circuit 14.
P is counted and the count value is led to the latch circuit 16.

Here, the output signal pa (FIG. 4d) of the pulse forming circuit I is used to determine the timing of lunch.

That is, the output Pa of the pulse forming circuit is connected to the inverter 17 of the timer circuit 8 and the delay ruff flop circuit 1.
8 and is applied to AND circuit 19 via respective circuits 17 and 18.

Therefore, the AND circuit 19 outputs a pulse PR as shown in FIG.

When the latch circuit 16 completes latching the count value, the count value of the counter 15 is reset.

The step signal P is used to determine the timing of this reset.

That is, the step signal P is inverted by the inverter 20 and applied to the counter 15 as a reset signal as shown in the fourth diagram, and the moment the reset signal rises to 1'' (that is, when the key is released), the counter 15 is inverted. Reset the count value.

When the key is pressed again, this reset signal falls to O'', and the counter 15 starts counting.

As described above, a count value corresponding to the key touch speed is taken out from the latch circuit 16.

Then, this count value is added to the musical tone forming circuit 2, and a musical tone is formed according to the key touch speed.

In the above embodiment, a photosensitive resistor R2 is used as the variable resistor R2, but the resistor R2 is not limited to this, and the resistance value may be directly changed by a key (a so-called variable volume).

As explained above, according to the present invention, it is possible to obtain a digital output in response to an initial key touch without using a resistor ladder circuit, and therefore costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a detailed example of the touch detection section in FIG. 1, and FIG. 3 is a block diagram showing a detailed example of the touch detection section in FIG. 2. FIG. 4 is a perspective view showing an example of the key mechanism, and is an explanatory diagram of the operation of FIG. 2. 1... Key switch, 2... Musical tone forming circuit, 3... Sound system, 4...
・Touch detection unit, 5...Key press signal generation circuit, 6
...Variable delay circuit, 7...Ladleless forming circuit, 8...Timer circuit, 10...Lamp, 13...Oscillator, Sl...Slit.

Claims (1)

[Scope of Claims] 1. A key press signal generation circuit that generates a key press signal indicating that a key is being pressed; and a key press signal generation circuit that inputs the key press signal and uses the rising edge of the signal as an initial key touch such as a key press speed. variable delay means for delaying output by a period of response/rejection, a pulse forming circuit for logically synthesizing the key press signal before the delay and the key press signal after the delay, and measurement for measuring the pulse width of the output pulse of the pulse forming circuit. A touch response device for an electronic musical instrument, comprising: a touch response circuit; and a touch response device for an electronic musical instrument, wherein the measured value of the measuring circuit is used for forming musical tones. 2. The variable delay means includes an integrating circuit that is charged by the key press signal before the delay and whose time constant changes in response to an initial key touch, and that the variable delay means is charged with the pre-delay key press signal and has a time constant that changes according to the initial key touch, and that the variable delay means is configured to adjust the voltage to the set voltage after charging of the integrating circuit is started. 2. The touch response device for an electronic musical instrument according to claim 1, wherein the touch response device for an electronic musical instrument is a circuit that delays the rise of the key press signal by utilizing the fact that the time it takes for the key press signal to reach the key press changes depending on a time constant. 3. Claim 1, wherein the measuring circuit is a circuit comprising an oscillator that generates clock pulses, and a counter that counts the clock pulses generated while the pulses are being output from the pulse forming circuit. A touch response device for the electronic musical instrument described above.