JPS6325680B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electronic musical instrument that generates musical tones using a sine wave synthesis method, which compresses envelope information and generates musical tone signals that resemble natural musical instrument sounds.

Conventionally, when trying to generate a musical sound that closely resembles the sound of a natural instrument by sine wave synthesis, a sine wave signal with a fundamental frequency and a number of sine wave signals corresponding to frequencies that are integral multiples of the fundamental frequency are generated, and each of them is The desired musical tone was obtained by independently multiplying the envelope signal by an envelope signal. However, according to this method, it is necessary to generate envelope signals individually for each sine wave signal, so a huge amount of envelope information is required.

If we consider the timbre of natural instruments here, the timbre of natural instruments is determined by the fundamental wave and its harmonics.
Usually, higher harmonics have a much lower level than lower harmonics, and their contribution to tone is smaller. However, if these high-order harmonics are not included when performing musical tone synthesis, the sound will be far from the sound of a natural musical instrument without a bow. Furthermore, natural musical instrument sounds usually have a distinctive characteristic in their rising part, and higher harmonics often have a considerable level in this part.

The present invention has been made in view of the above points, and it is an object of the present invention to provide an electronic musical instrument that compresses envelope information and generates musical sound signals that are similar to natural musical instrument sounds.

The present invention will be explained below based on the drawings.

FIG. 1 shows an embodiment of an electronic musical instrument according to the present invention. Referring to FIG. 1, envelope memories 1-1 to 1-n store envelope information corresponding to musical tone signals to be generated. In this embodiment, the contents of envelope memory 1-1 start from address 0 as shown in FIG.
It consists of 128 pieces of data up to address 127. Addresses 0 to 31, shown in section 1, are the attack part of the musical tone, and addresses 32 to 86, shown in section 2, are the sustain part of the musical tone. 87~ indicated by 3
Address 127 is the release section. In order to simplify the description below, n of envelope memory 1-1 is
The contents of the envelope information within the address will be expressed as D _H (n). Also, envelope memory 1-
Envelope information similar to the envelope information shown in FIG. 2 is also stored in n. 2-1
~2-m is also an envelope memory, and the contents of envelope memory 2-1 are 0 as shown in Figure 3.
It consists of 32 pieces of data from address to address 31, and only information about the attack part of musical tones is stored. The envelope memory 2-m also stores envelope information having the same amount of information as the envelope information shown in FIG. In addition, in this embodiment, envelope memories 1-1 to 1-n,
Envelope information of values converted into decibel values is stored in 2-1 to 2-m. 3-1～
3-m is a subtracter that subtracts a predetermined value from the input signal. In this embodiment, the subtracter 3-1
subtracts {D _1-1 (31) − D _2-1 (31)} from the input signal, and subtractor 3-m inputs {D _1-1 (31) − D _2-n (31)}. Subtract from the signal. As is clear from these formulas, all of the subtracters 3-1 to 3-m are
Subtract the difference between D _1-1 (31) and D _2-1 (31) to D _2-n (31) from each input.

4-1 to 4-m are selectors which select and output either the A terminal or the B terminal according to the signal applied to the C terminal. In this embodiment, when "0" is given to the C terminal, each A
The signal given to the terminal is outputted, and when "1" is given, the signal given to each B terminal is outputted. 5 is an address control circuit;
Envelope memories 1-1 to 1-n, 2-1 to 2- are stored based on key press signals K _p given by key presses.
The address signal A _c is sent to m, and the envelope information is read out. Also, selector 4
A control signal C _p is sent to -1 to 4-m. 6
is an opening/closing signal generator, which generates an opening/closing signal _K1 in response to a key press signal _Kp .

Note that the address signal A _c , key press signal K _p , control signal C _p and open/close signal sent by the address control circuit 5
The relationship of K ₁ is as shown in Figure 4.
That is, when a key is pressed, the key press signal K _p becomes "1", and the address signal A _c first outputs "0", and then counts up sequentially as "1", "2", "3", etc. However, the key release time is the address signal.
The opening/closing signal _K1 is different depending on whether before and after the value of A _c reaches "86", that is, whether or not reading of section 2 has been completed in the envelope memory 1-1. FIG. 4A shows a case in which the key is released before the value of the address signal A _c reaches "86".
In other words, when the key is pressed and the key press signal K _p becomes "1", the address signal A _c starts from "0",
The count will be increased sequentially. Also, open/close signal
K ₁ outputs its maximum value at the same time as the address signal A _c becomes "0", and when the key press signal K _p becomes "0", it gradually attenuates in synchronization with the address signal A _c .

By the way, if the value of the address signal A _c reaches "86" while the key is still pressed, the value of the address signal A _c stops at "86" and starts counting again after the key is released, as shown in Figure 4B. It's getting more and more popular. Also,
If there is no new key pressed after the key is released, the address signal
The value of A _c counts up to “127” and then stops.
On the other hand, the open/close signal K ₁ is the address signal A _c at the same time as the key is pressed.
It rises to its maximum value in synchronization with the key, but it always maintains a constant value without rising even after the key is released. On the other hand, the control signal C _p is "0" when the value of the address signal A _c is between "0" and "31" and " 1”.

The above is a description of the address signal A _c control signal C _p and the opening/closing signal K ₁ output by the address control circuit 5 and the opening/closing signal generator 6.

7-1 to 7-n and 9-1 to 8-m are sine wave generators that generate sine wave signals. In this embodiment, the sine wave generators 7-1 to 7-n, 9-1 to
The frequency of the sine wave signal generated by 8-m is an integral multiple of the signal frequency of the sine wave generator 7-1, which is a reference sine wave generator, that is, it has a harmonic relationship.

Multipliers 9-1 to 9-n and 10-1 to 10n multiply two input signals and output a musical sound waveform. In this embodiment, envelope memories 1-1 to 1-n, 2-1 to 2-m
Since the envelope information stored in the ROM is expressed in decibels, the envelope information is read out from the ROM and subjected to decibel/linear conversion, and then multiplied by the sine wave signal. 11 is an adder, and multipliers 9-1 to 9-n, 10-1
The outputs of ~10-m are added. Reference numeral 12 denotes a switch, which opens and closes the output of the adder ₁₁ based on the switching signal K1. 13 is a DAC (digital/analog converter).

Next, the operation of the circuit shown in FIG. 1 will be explained with reference to FIG.

When the key press signal K _p rises due to a key press, the address control circuit 5 sends out the address signal A _c and the opening/closing signal generator 6 sends out the opening/closing signal K ₁ as shown in FIGS. 4A and 4B. As a result, first, the envelope memory 1-1 outputs an envelope signal based on the read signal. In addition, envelope memory 2-1
also outputs an envelope signal (Fig. 5B). The output of envelope memory 1-1 is multiplied by a sine wave signal generated by sine wave generator 7-1 in multiplier 9-1, and sent to adder 11. The output of envelope memory 2-1 is given to selector 4-1. Here, when the address signal after key depression is "0" to "31", the control signal C _p
is "0", the selector 4-1 selects the output of the envelope memory 2-1, and the multiplier 10-1 selects the output of the envelope memory 2-1.
send to. Next, when the key continues to be pressed and the address signal A _c becomes "32", the control signal C _p becomes "1".
becomes. Therefore, the selector 4-1 selects and sends out the output of the subtracter 3-1 input to the B terminal. Here, the output of the subtracter 3-1 will be considered using FIG. As described above, the subtracter 3-1 subtracts {D _1-1 (31)-D _2-1 (31)} from the input signal. Therefore, when the address signal A _c indicates "32", the output of the subtracter 3-1 is D _1-1 (32) - {D _1-1 (31) - D _2-1 (31)} = D _2-1 (31) − {D _1-1 (32) − D _1-1 (31)} (Figure 5A). Since the output of selector 4-1 when the address signal is "31" is D _2-1 (31), when the address signal becomes "32", {D _1-1
(32)−D _1-1 (31)} The output of the selector 4-1 changes by an amount equal to (32)−D 1-1 (31)}. This is the same amount of change in the output of the envelope memory 1-1 when the selector 4-1 switches the output. Therefore, it can be seen that the output envelope signals are smoothly connected when the output of the selector 4-1 is switched (FIG. 5C, t=31τ). In this way, even though the envelope memory 2-1 only contains envelope information for the attack part of a musical tone, the selector 4-1 can generate a smooth envelope signal from the sustain part to the release part. Can be done. selector 4
The output of -1 is sent to the multiplier 10-1, multiplied by the sine wave generated by the sine wave generator 8-1, and then sent to the adder 11.

Similarly, the other multipliers 9-n and 10-m output sine wave signals multiplied by the envelope signals, and the adder 11 adds them.
As mentioned above, the sine wave generators 7-1 to 7-n, 8-
Since the frequencies of the signals outputted by 1 to 8-m are in a harmonic relationship, the output of the adder 11 is synthesized into a sine wave in which each harmonic has an independent envelope.

On the other hand, when the key press signal K _p becomes "1",
As shown in FIG. 4, the opening/closing signal _K1 rises. This switching signal _K1 causes the switch 12 to send the output of the adder 11 to the DAC 13 without attenuating it. Next, when the key is released, the key press signal K _p becomes “0”
becomes. If the value of the address signal A _c output by the address control circuit 5 at this point is smaller than "86", the opening/closing signal K ₁ begins to attenuate as described above. Therefore, the output of the switch 12 attenuates together with the switching signal _K1 .

As described above, the musical tone signal attenuates at the same time as the key is released.

Further, if the address signal A _c at the time of key release is "87" or more, the opening/closing signal does not change as shown in FIG. 4B. However, since the address control circuit 5 reads the release part (section 3) in the envelope memories 1-1 to 1-n, the adder 1
1's output is attenuated. Therefore, the output of the switch 12 also decreases. The output of this switch 12 is DAC
13, it is converted into an analog musical tone signal and output.

Considering the output of the adder 11 here, at the rising edge of the musical tone signal, the sine wave generator 7
Since the envelope signals are independently multiplied by the sine wave signals generated by all of -1 to 7-n and 8-1 to 8-m, the tones are very similar to natural musical instrument sounds. Also, in the steady part (sustain part), the lower harmonics are the envelope memory 1-
Since 1 to 1-n are read out sequentially, the sound quality of a natural instrument is not impaired. In addition, in the case of higher harmonics, the formant is maintained and they undergo fluctuations in the same way as the fundamental wave, so the musical sound does not have any unnaturalness, and since the level is originally low, there is no difference from the sound of natural instruments. Inconspicuous.

In the above explanation, all the envelope information after the sustain section for high-order harmonics is generated using the envelope information of the fundamental wave. It goes without saying that envelope information may also be used. In addition, the envelope information after the sustain section for higher-order harmonics is set so that some harmonics are generated using the envelope information of the fundamental wave, and others are generated using envelope information other than the fundamental wave. You can also do this. Also, envelope memory 2
-1 to 2-m, in this embodiment only the attack part of the musical tone is stored, but part of the attack part and the sustain part may also be stored, or depending on the musical tone, a part of the attack part may be stored. Alternatively, the envelope information of the lower harmonics may be used for all of the envelope information of the higher harmonics from the attack part to the release part, and the higher harmonic envelope memory may be omitted. Conversely, even if it is a high-order harmonic,
It goes without saying that envelope information for all of the attack section, sustain section, and release section may be stored in the envelope memory.

Also, regardless of the harmonic order, for those that should generate a sine wave signal below a certain level,
Omit some or all of the envelope memory,
It goes without saying that the envelope signal may be generated using other envelope information.

In addition, the envelope memory 1- in FIG.
1 to 1-n and 2-1 to 2-m, an envelope generator consisting of an envelope memory 1-1 and an interpolation circuit 14 as shown in FIG. 6 may be used.

The operation of FIG. 6 will be explained together with the output waveforms of envelope memory 1-1 and interpolation circuit 14 shown in FIG.

The address control circuit 5 generates an address signal A _c in response to the key press signal K _p , and the envelope memory 1 -
The operation leading to reading the envelope information from 1 is the same as that shown in FIG. When the envelope memory 1 outputs envelope signals at time intervals as shown in FIG. 7a, the interpolation circuit 14 replenishes envelope signals at intervals of τ/4 based on the envelope signals. This allows the frequency of the clock signal to be lowered and the capacity of the envelope memory to be reduced.

Further, the interpolation circuit 14 may be provided immediately after the envelope memory 1-1 as shown in FIG. 6, or the multipliers 9-1 to 9-n, 10-1 to 10-n
It may be placed immediately before.

As described above, according to the present invention, for high-order harmonics, the envelope information is compressed by having only the envelope information of the attack part of the musical tone, and at the same time, the musical tone signal that is typical of the sound of a natural instrument is generated. The excellent effect of generation can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an electronic musical instrument according to the present invention, FIGS. 2 and 3 are diagrams showing envelope information stored in the envelope memory of the above embodiment, and FIG. A timing diagram showing the relationship among the key press signal, address signal, opening/closing signal, and control signal in the example; FIG. 5 is a waveform diagram showing the input/output of the attenuator and selector in the above embodiment; FIG. 6 is a waveform diagram that can be used in the present invention. FIG. 7 is a block diagram showing the envelope generator, and FIG. 7 is an input/output waveform diagram of the interpolation circuit shown in FIG. 1-1 to 1-n, 2-1 to 2-m...Envelope memory, 3-1 to 3-m...Subtractor, 4-1
~4-m... Selector, 5... Address control circuit, 7-1 to 7-n, 8-1 to 8-m... Sine wave generator, 9-1 to 9-n, 10-1 to 10 -m...
...multiplier, 11...adder, 14...interpolation circuit.

Claims (1)

[Claims] 1. A sine wave generator that generates a sine wave signal, an envelope storage device that stores envelope information, an envelope generator that generates an envelope signal based on the envelope information, and a combination of the sine wave signal and the envelope signal. a multiplier that performs multiplication, and a plurality of waveform generators that use the output of the multiplier as a scale signal; the plurality of scale signals are added to obtain a musical tone signal; The frequencies are each an integral multiple of the reference frequency, and the envelope storage device in at least one of the plurality of waveform generators releases the signal from the attack portion of the scale signal to be generated. The envelope storage device in the waveform generator of another set stores the envelope information of the attack part of the scale signal to be generated, and the envelope generator of the set stores the envelope information of the attack part of the scale signal to be generated. The attack part of the scale signal to be generated is generated based on the envelope information of the set, and the parts other than the attack part are generated based on the envelope information of another set of waveform generators having envelope information other than the attack part. An electronic musical instrument characterized by: