JPS6365155B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic musical instrument that reads a musical sound waveform stored in a ROM when a key is pressed and obtains a musical sound signal by multiplying it by an envelope signal. The musical tone immediately and smoothly begins to decay immediately after the sound is played, and it is possible to add a falling sound that is very similar to the falling sound characteristic of natural musical instruments.

Conventionally, as a method of generating natural musical instrument sounds,
The waveform for one period of the musical tone to be generated is stored in ROM.
There is a method in which the sound waveform is stored in a ROM, etc., and the ROM is read out to generate a musical sound waveform, which is then multiplied by an envelope signal stored separately in advance. In other words, an envelope waveform as shown in Figure 1 is stored in a ROM, etc., and the contents of the ROM are reset to 0 using an address counter or the like at the same time as the key is pressed.
It is read from the address and multiplied by the musical sound waveform read from another ROM. However, with this method, if you release the key and stop the address counter once the contents of address 47 have been read out, the contents of address 47 in the ROM will always be output, resulting in the problem that the musical tone will not decay. There is.
Furthermore, if the address counter continues to operate after the key is released, the musical tone will attenuate, but it will take a considerable amount of time from the time the key is released until the attenuation starts, which is not practical.

The present invention has been made in view of the above points, and will be explained below based on the drawings.

FIG. 2 shows one embodiment of the present invention. In FIG. 2, reference numerals 1-1 to 1 to n are musical tone generators, which generate weighted sine waves. Reference numeral 2 denotes an envelope memory, which stores envelope information corresponding to a musical tone signal to be generated. In this embodiment, the contents of the envelope memory 2 are from address 0 to 127 as shown in FIG.
It consists of 128 pieces of data up to the address, and addresses 0 to 86, indicated by section 1, are the attack and address of musical tones.
Addresses 87 to 127 shown in the sustain section and section 2 are the release section. 3 is a sine wave generator, which generates a sine wave signal. 4 is a multiplier;
The two input signals are multiplied and output.
Reference numeral 5 denotes an address control circuit, which sends a read signal Ac to the envelope memory 2 based on a key press signal _K0 given by a key press, etc., and reads envelope information. Reference numeral 6 denotes an adder, which adds the musical waveforms output from the musical tone generators 1-1 to 1-n. 7 is a switching signal generator;
An open/close signal _K1 is generated based on the key press signal _K0 and the readout signal Ac. 8 is a switch, which opens and closes the output of the adder 6 based on the switching signal _K1 .
9 is a DAC (digital/analog converter).

The relationship between the readout signal Ac sent out by the address control circuit 5, the key press signal _K0 , and the opening/closing signal _K1 is as shown in FIG. That is, when the key is pressed, the key press signal _K0 becomes "1", and the read signal Ac first outputs "0", then "1", "2", and "3".
The count is sequentially increased, but the key release time is before and after the value of the readout signal Ac reaches "86".
In other words, the opening/closing signal _K1 differs depending on whether reading of section 1 in the envelope memory 2 has been completed or not.

FIG. 3A shows a case where the key release time is before the value of the read signal Ac reaches "86". That is, when the key is pressed and the key press signal _K0 becomes "1", the read signal Ac starts from "0" and is sequentially counted up. When the key is then released, the key press signal _K0 becomes "0", but the read signal Ac is sequentially counted up. Next, when the key is pressed again, the read signal Ac is reset to "0" and then sequentially counted up. On the other hand, the opening/closing signal _K1 rises to its maximum value at the same time as the readout signal Ac becomes "0", and decays exponentially when the key press signal _K0 becomes "0".

FIG. 3B shows a case where the key is continued to be pressed even after the value of the read signal Ac reaches "86", and the key is released after a while. In other words, the read signal Ac is “86”
If the key continues to be pressed even after , the value of the read signal Ac stops at "86" and is counted up again after the key is released. Further, if there is no new key pressed after the key is released, the value of the read signal Ac counts up to "127" and then stops. On the other hand, the opening/closing signal _K1 rises to its maximum value in synchronization with the readout signal Ac at the same time as the key is pressed, but it always maintains a constant value without falling even after the key is released.

In addition, in the above embodiment, the musical tone generator 1-1
~1-n all have the same configuration, but the contents stored in the envelope memory 2 and the frequency of the generated sine wave signal are different, and the frequency of the sine wave signal is different from that of the reference sine wave generator. is an integer multiple of the signal frequency, that is, has a harmonic relationship.

Next, the operation of the embodiment shown in FIG. 2 will be explained with reference to FIG. 4. In order to simplify the explanation, only the signal output from the musical tone generator 1-1 will be described here.

When the key press signal _K0 rises due to a key press, the address control circuit 5 sends the readout signal Ac to the envelope memory 2, and the open/close signal generator 7 sends the open/close signal _K1 to the switch 8, as shown in FIGS. 3A and 3B. , respectively. As a result, first, the envelope memory 2 outputs an envelope signal based on the read signal Ac (FIG. 4A). On the other hand, sine wave generator 3
outputs a sine wave signal, this sine wave signal is multiplied by the aforementioned envelope signal in multiplier 4, and output from musical tone generator 1-1. Similarly, the other tone generators 1-n output sine wave signals multiplied by envelope signals, and the adder 6 adds them. At this time, as mentioned above, since the frequencies of the signals output from each musical tone generator 1-1 to 1-n are in a harmonic relationship, the output of the adder 6 has a plurality of harmonics having independent envelopes. It becomes a sine wave composite.

On the other hand, when the key press signal K ₀ becomes "1",
As shown in FIG. 3, the opening/closing signal _K1 rises (FIG. 4B). With this switching signal _K1 , the switch 8 sends the output of the adder 6 to the DAC 9 without attenuating it (0≦t≦τ in FIG. 4C). Then t=
When the key is released at τ, the key press signal _K0 becomes "0". At this point, the address control circuit 5 is outputting "53", which is smaller than "86" mentioned in Fig. 3, so the opening/closing signal _K1 begins to attenuate (Fig. 4B, t>τ). . Therefore, the output of switch 8 is the switching signal K ₁
(t>τ in Fig. 4C). Similarly, the output signals of the other tone generators 1-n are attenuated by the switch 8.

As described above, since the musical tone signal attenuates at the same time as the key is released, the problem of continuing to output the contents of the ROM at the address at the time of the key release can be solved.

Further, if the key is pressed for a sufficiently long time, the read signal Ac stops at "86" as described in FIG. 3, and starts counting up at the same time as the key is released. Therefore, the release part of section 2, which is from address 87 onwards, is immediately read out from the envelope memory 2, and the musical tone begins to attenuate at the same time as the key is released.

As described above, according to the above embodiment, the musical tone signal can be attenuated quickly and smoothly after the key is released, regardless of how long the key is pressed.

In the above embodiment, the opening/closing signal generator 7 generates an opening/closing signal that decays exponentially. It goes without saying that if this is done, it is possible to generate musical tones that are even closer to those of natural musical instruments. In addition, the sine wave generator 3
Instead, a waveform generator that repeatedly generates one waveform of a musical tone may be used.

FIG. 5 shows another embodiment of the invention. In FIG. 5, parts having the same functions as those in FIG. 2 are designated by the same reference numerals, and detailed explanations will be omitted. 10 is a three-input multiplier.

Next, the operation shown in FIG. 5 will be explained. The basic operation is the same as the circuit shown in Figure 2, so the second
The explanation will be given using FIG. 4 as in the case of the figure.

When the key press signal _K0 rises due to a key press, the address control circuit 5 sends out the read signal Ac and the open/close signal generator 7 sends out the open/close signal _K1 , as shown in FIGS. 3A and 3B. As a result, first, the envelope memory 2 outputs an envelope signal based on the read signal Ac (FIG. 4A). On the other hand, sine wave generator 3
outputs a sine wave signal. Furthermore, when the key press signal becomes "1", the opening/closing signal _K1 rises as shown in FIG. 3 (FIG. 4B). This open/close signal
_K1 , the aforementioned sine wave signal, and envelope signal are multiplied by the multiplier 10, and the result is output from the musical tone generator 1-1. In the other musical tone generators 1-n, the envelope signal, the sine wave signal, and the opening/closing signal _K1 are multiplied in the same way, and the obtained output is sent to the adder 6.
Add with . Here again, as mentioned above, the frequencies of the signals output from each musical tone generator 1-1 to 1-n are in a harmonic relationship, so the output of the adder 6 has a plurality of harmonics having independent envelopes. It becomes a sine wave composite.

Considering the output of the multiplier 10 here, while the key is pressed (0≦t≦τ in Fig. 4), the open/close signal _K1 continues to output its maximum value, so the output of the envelope memory 2 is Outputs a signal equivalent to a signal multiplied by a sine wave. Next, when the key is released at t=τ, the key press signal K ₀ becomes "0".
At this point, the address control circuit 5 is outputting "53", which is smaller than "86" mentioned in Fig. 3, so the opening/closing signal _K1 starts to attenuate (Bt>
τ). Therefore envelope signal, sine wave, open/close signal
The output of the multiplier 10 multiplied by K ₁ also opens and closes the attenuation (FIG. 4C, t>τ).

As described above, since the musical tone signal attenuates at the same time as the key is released, this embodiment also solves the problem of continuing to output the contents of the ROM at the address at the time of the key release.

Further, if the key is pressed for a sufficiently long time, the read signal Ac stops at "86" as described in FIG. 3, and starts counting up at the same time as the key is released. For this reason, envelope memory 2 to 87
After the address, that is, the release portion of section 2 is read out, and the output of the multiplier 10 begins to attenuate at the same time as the key is released.

As described above, in the embodiment shown in FIG. 5 as well, the musical tone signal can be attenuated quickly and smoothly after the key is released, regardless of the length of time the key is pressed. Further, in the embodiment shown in FIG. 5, in each musical tone generator 1-1 to 1-n, each opening/closing signal generator 7
Since the opening/closing signal _K1 generated by the DAC 9 can be arbitrarily selected, the falling edge of the musical tone signal output from the DAC 9 can be made to be very similar to that of a natural musical instrument.

FIG. 6 shows an improved version of the multiplier 10 in FIG. In FIG. 6, 11 is an adder and 12 is a converter, which performs logarithmic/linear conversion. When using the multiplier shown in Figure 6,
The envelope signal and the opening/closing signal _K1 are converted into logarithms in advance. That is, the envelope memory 2 stores envelope information in logarithmic representation, and the opening/closing signal generator 7 also outputs the opening/closing signal in logarithmic representation. Multiplier 1 like this
Using 0 can save calculation time.

In the above explanation, the opening/closing signal generator 7 may be of any type as long as it generates a signal as shown in FIG.
As shown in the figure. In FIG. 7, 13 is a comparator, which compares the read signal Ac generated by the address control circuit 5 with a predetermined value, "86" in the above embodiment, and when {read signal Ac}≦86, It outputs "1". A latch 14 latches the signal applied to the D terminal at the rising edge of the CK terminal and outputs it from the Q terminal. 15 is a clock generator. 16 is a 5-bit counter that counts the signal applied to the CK terminal. Also, the signal given to the R terminal is “1”
, the output is reset unconditionally. 17
is a memory, which has 32 pieces of information from addresses 0 to 31, and stores information to be output as opening/closing signals. The contents of the memory 17 are as shown in FIG.

Next, the operation of the switching signal generator 7 shown in FIG. 7 will be explained.

First, when the key press signal K ₀ becomes “1”,
Since the R terminal of the counter 16 becomes "1", all counter outputs are reset to "0". Therefore, while the key is being pressed, the contents of address 0 of the memory 17 are always output. Next, when the key is released and the key press signal _K0 becomes "0", the inverter 18 turns the latch 14 CK.
The input signal at the terminal rises, and the output of the comparator 13 is latched. Therefore {read signal Ac}>
When the signal is 86, the output of the latch 14 is "0", and when {read signal}≦86, the output of the latch 14 is "1".

When {read signal Ac}>86, the output of the latch 14 is "0", so the output of the AND circuit 19 is always "0", and the counter 16 remains stopped in the reset state. The contents of the address are output, and the output of the open/close signal generator 7 does not change even when the key is released.

On the other hand, when {read signal Ac}≦86, the output of the latch 14 is "1". Since the counter 16 has been reset, the output of the NAND circuit 20 is also "1". Therefore, the AND circuit 19 outputs the clock signal generated by the clock generator 15 and applies it to the CK terminal of the counter 16. After the key is released, the input signal to the R terminal of the counter 16 is "0", so the counter 16 starts counting the clock signal applied to the CK terminal and outputs it to the memory 17. The memory 17 sequentially reads and outputs the memory contents based on the output of the counter 16. Since the contents of the memory 17 are as shown in FIG. 8, the output of the switching signal generator 7 gradually attenuates. Here, the counter 16 continues counting the clock signal, and when all 5 bits output become "1", that is, the last content of the memory 17 is read out.
The output of the NAND circuit 20 becomes "0", and the output of the AND circuit 19 also becomes "0". Therefore counter 16
No clock signal is given to the CK terminal of
The counter 16 stops with the output still showing "31". As a result, the memory 17 outputs the contents of address 31 up to the new key press.

The above is the operation of the switching signal generator 7 shown in FIG. When the opening/closing signal generator 7 is configured as shown in FIG. 7, it is possible to give various falling tones depending on the content stored in the memory 17.
And it's extremely easy to do.

FIG. 9 shows an embodiment in which an envelope memory 2 and an interpolation circuit 21 are used in place of the envelope memory 2 in FIGS. 2 and 5.

Next, the operation shown in FIG. 9 will be explained together with the output waveforms of the envelope memory 2 and interpolation circuit 21 shown in FIG. 10.

The address control circuit 5 generates the read signal Ac in response to the key press signal _K0 , and the operation leading to reading the envelope information from the envelope memory 2 is performed in the second step.
It is the same as that shown in FIG. 10th
When the envelope memory 2 outputs envelope signals at time intervals as shown in FIG. In this way, the frequency of the clock signal can be lowered, and the capacity of the envelope memory can be reduced.

It goes without saying that the circuit shown in FIG. 9 may be applied to the memory 17 in FIG.

Further, in the above embodiments, a case has been described in which a single musical tone is generated, but it goes without saying that envelope memories, multipliers, etc. can be used in a time-sharing manner to generate multiple tones.

As described above, according to the present invention, the musical tone starts to decay immediately and smoothly after the key is released, regardless of how long the key is held down, and the decay is very similar to the decay characteristic of natural musical instruments. The excellent effect of being able to add

[Brief explanation of drawings]

FIG. 1 is a diagram showing envelope information stored in a general envelope memory, and FIG. 2 is a block diagram showing an embodiment of an electronic musical instrument according to the present invention.
Figure 3 is a diagram showing the relationship between the key press signal, readout signal, and open/close signal; Figure 4 is a diagram showing the relationship between the envelope signal, open/close signal, switch output, and key press signal;
FIG. 6 is a block diagram showing another embodiment of the present invention, FIG. 6 is a diagram showing an example of the multiplier in FIG. 5, FIG. 7 is a diagram showing an example of the switching signal generator, and FIG. Diagram showing memorized contents, No. 9
The figure shows a case where envelope information is generated by interpolating envelope information, and FIG. 10 is an output waveform diagram of the interpolation circuit shown in FIG. 9. 1-1 to 1-n...musical tone generator, 2...envelope memory, 3...sine wave generator, 4...multiplier, 5...address control circuit, 6...adder, 7
... Switching signal generator, 8 ... Switch, 10 ... Multiplier, 11 ... Adder, 12 ... Converter, 13 ...
... Comparator, 14 ... Latch, 15 ... Clock generator, 16 ... Counter, 17 ... Memory, 21 ... Interpolation circuit.

Claims (1)

[Claims] 1 means for generating a key press signal by key press/release;
a waveform generator that generates a musical sound waveform; an envelope storage device that stores envelope information consisting of an attack section, a sustain section, and a release section of a musical tone; and a readout device that sequentially reads out the contents of the envelope storage device based on the key press signal. an address control device that generates a signal; an envelope generator that reads the envelope information based on the readout signal and generates an envelope signal; an arithmetic unit that performs amplitude modulation of the musical sound waveform based on the envelope signal; and the key press signal. an opening/closing signal generator that generates an opening/closing signal based on the above, and the opening/closing signal generator has release detection means for detecting a release part of the envelope information, and the release detection means detects the release part of the envelope information. If the release detection means does not detect a release part of the envelope information, generates an opening/closing signal that does not attenuate the output of the computing unit, and generates an opening/closing signal that attenuates the output of the computing unit with predetermined characteristics when the release detection means does not detect a release portion of the envelope information. An electronic musical instrument characterized by being an opening/closing signal generator.