JPS5921038B2 - electronic musical instruments - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is capable of generating musical tones by synthesizing first and second waveforms that have a frequency corresponding to the pitch of the generated musical tones and have different waveform shapes. This relates to a type of electronic musical instrument that forms a waveform, and in particular, it has a simple configuration and can arbitrarily change the synthesis ratio of the first and second waveforms to create a tone corresponding to the first waveform. It is possible to freely generate musical tones having arbitrary tones up to the tones corresponding to the waveforms of No. 2.

(Prior Art) Electronic musical instruments of the so-called waveform memory read method, which generate musical sound waveforms by reading out waveforms stored in a waveform memory using read address signals corresponding to pressed keys, have been known in the past.

In this type of electronic musical instrument, in order to arbitrarily change the shape of the musical sound waveform and enrich the range of timbre changes, two waveform memories that store waveforms with different shapes are installed in parallel. In some cases, the waveforms are read out simultaneously from these two waveforms, and after variable control of the waveform level is performed, the read out waveforms are added to form a musical sound waveform.

In this way, by appropriately setting the level of each waveform, it is possible to arbitrarily change the timbre of the musical tone from the timbre corresponding to one waveform to the timbre corresponding to the other waveform. However, for this purpose, it is necessary to provide a multiplier for waveform level setting and a parameter generator for generating a level setting parameter signal on the output side of each waveform memory.

That is, the overall structure becomes more complicated and the cost increases. In particular, since digital multipliers are generally more expensive than adders, it is very disadvantageous in terms of cost to use a plurality of them. Further, when the above method is used, if the value of the level setting parameter signal for each waveform changes, the level of the musical sound waveform obtained by combining both waveforms may also change. In order to prevent this, there is also the problem that special measures are required when setting the values of each parameter signal. (Object of the Invention) The present invention was proposed in view of the above-mentioned drawbacks of electronic musical instruments that form a musical sound waveform by combining two waveforms of different shapes.

That is, it is an object of the present invention to make it possible to arbitrarily change the synthesis ratio of both waveforms with a simple configuration, and to ensure that the level of the musical sound waveform formed is not affected by changes in the synthesis ratio. . (Basic Configuration of the Invention) According to the invention, a first waveform generation circuit that generates a first waveform W1 of first and second waveforms having different shapes;
A second waveform generation circuit is provided that generates a waveform (W2-W1) corresponding to the difference between the first waveform W1 and the second waveform W2.

Waveform generated from the second waveform generation circuit (W2-W1)
First, in the multiplier, the parameter signal P for setting the synthesis ratio is
is multiplied by
-P)} are synthesized. (Embodiment) FIG. 1 shows an embodiment of the present invention.

The keyboard circuit 1 in the figure has a plurality of output lines corresponding to keys, and when a certain key is pressed, a logic value of "1" is output to the output line corresponding to that key. has a built-in single note priority circuit, which determines only one note to be produced even if two or more keys are pressed at the same time.
-29918 can be used. Furthermore, the keyboard circuit 1 has a function of outputting a key-on signal KON indicating that a certain key has been pressed. The output line of the keyboard circuit 1 is connected to the input side of a frequency information memory 2, and this frequency information memory 2 stores frequency information corresponding to the pitch of each key. That is, when a certain key is pressed, frequency information corresponding to that key is read from the frequency information memory 2. The output side of the frequency information memory 2 is connected to an accumulator 3.

This accumulator 3 receives the clock pulse φ and sequentially accumulates the frequency information output from the frequency information memory 2.
The accumulated value is output as an address signal. This address signal is input to the tone waveform generator 4. As will be described later, the tone waveform generator 4 receives the address signal output from the accumulator 3 and sequentially generates the waveform amplitude value of the tone waveform corresponding to the address specified by the address signal. It is.

The output side of the musical waveform generator 4 is connected to a first input terminal of a multiplier 5.

Further, the output side of the envelope waveform generator 6 is connected to the second input terminal of the multiplier 5 . Furthermore, the output of the multiplier 5 is connected to a sound system 7. The sound system 7 includes an amplifier, a speaker, etc., and generates musical tones based on the musical waveform output from the multiplier 5. Therefore, the musical sound waveform output from the musical sound generator 4 is multiplied by the envelope waveform output from the envelope waveform generator 6 in the multiplier 5, and thereby the musical sound waveform with an appropriate volume envelope is sent to the sound system 7. The sound system 7 generates musical tones based on this input.

Note that the envelope waveform generator 6 is connected to the keyboard circuit 1.
The device receives a key-on signal output from the controller and outputs the above-mentioned envelope waveform. Here, envelope waveforms can be roughly divided into percussive tone waveforms shown in Figure 2A and sustained tone waveforms shown in Figure 2B. By operating it, one of the waveforms can be arbitrarily selected. Next, returning to FIG. 1, the musical sound waveform generator 4 will be described in detail.

This musical waveform generator 4 first has two waveform memories 21,
22, which are connected in parallel to the output of the accumulator 3. The output side of the waveform memory 21 is connected on the one hand to a first input terminal A of an adder 30 and on the other hand to a second input terminal B of a subtracter 24. The output side of the waveform memory 22 is the first one of the subtracter 24.
is connected to input terminal A of. The output side of the subtracter 24 is connected to a first input terminal A of a multiplier 28 . The key-on signal KON from the keyboard circuit 1 is sent to the parameter generator 2.
6, and the output side of this parameter generator 26 is connected to a second input terminal B of a multiplier 28.

The output of the multiplier 28 is connected to the second input B of the adder 30, and the output of the adder is connected to the first input of the multiplier 5.

Here, one waveform memory 21 stores a waveform W1 with few harmonic components as shown in FIG. 3A, for example, and the other waveform memory 22 stores a waveform W1 with few harmonic components as shown in FIG. 3B, for example. A waveform W2 with many components is stored.

The subtracter 24 has a function of subtracting the signal input to its second input terminal B from the signal input to its first input terminal A.

The parameter generator 26 has a function of receiving the key-on signal KON and generating a parameter signal p(t) at the same time as the key is pressed.

When a percussive musical tone is selected, the parameter generator 26 generates a parameter signal p( as shown in FIG. 4A).
t) is output, and if a connecting tone type musical tone is selected, the fourth
A parameter signal p(t) as shown in Figure B is output.
Note that each time Tl, t2, and T3 in FIG. 4A corresponds to each time T of the barcussive tone envelope waveform shown in FIG. 2A.
1, t2 and T3, respectively. Also, Figure 4B
The times t1 to T5 in the middle correspond to the times t1 to T5 of the sustained tone envelope waveform shown in FIG. 2B, respectively. Here, as the parameter generator 26, a commonly used envelope waveform generator may be used as is, or a suitable ROM or the like may be used. The operation of the electronic musical instrument having the above configuration will now be described.

When a certain key is pressed, frequency information corresponding to that key is output from the frequency information memory 2, and this frequency information is sequentially accumulated in the accumulator 3 at the timing of the clock pulse φ to correspond to the pitch of the pressed key. A cumulative value that advances (changes in value) is obtained.

This accumulated value is sent to the waveform memory 21 as a read address signal.
, 22 are sequentially input. The waveform memories 21 and 22 receive this read address signal and sequentially output the waveform amplitude values stored at the designated addresses.

That is, the waveform memories 21 and 22 output waveforms Wl and W2 of frequencies corresponding to the pitches of the pressed keys, respectively. The waveforms Wl and W2 output from the waveform memories 21 and 22 are supplied to input terminals B and A of a subtracter 24, respectively, and the subtracter 24 outputs a waveform (W2-W1) corresponding to the difference between them.

This waveform (W2-W1) is multiplied by the parameter signal P(t) output from the parameter generator 26 in response to the key-on signal KON in the multiplier 28, and as a result, the waveform (W2-wl) is output from the multiplier 28.・P(t) is output. This waveform (W2-wl)·p(t) is supplied to the second input terminal B of the adder 30.

On the other hand, in parallel thereto, the output waveform W1 from the waveform memory 21 is supplied to the first input terminal A of the adder 30.
Therefore, both waveforms are added in adder 30, and adder 3
From 0, the musical sound waveform [W2・p(t)+wl・{1−p(
t)}] is output. This musical sound waveform [W2・p(t)
+W1.{1-p(t)}] is multiplied by an envelope waveform from an envelope waveform generator 6 in order to give a volume envelope in a multiplier 5, and is sent to a sound system 7 to be produced as a musical tone.

As is clear from the above description, the waveforms Wl and W2 read out from the waveform memories 21 and 22 by the read address signal output from the accumulator 3 are converted within the musical sound waveform generator 4, and are converted into musical sound waveforms [ W2・p(t)+w1・
It is output from the musical waveform device 4 as {1-p(t)}. This musical sound waveform [W2・p(t)+w1・{1−p(
t)}] changes in accordance with the parameter signal p(t).
The above changes will be explained when a percussive musical tone is selected. In this case, it is assumed that the parameter signal p(t) changes over time, for example, as shown in FIG. 4A. That is, the parameter signal p(t) is t1 when the key is pressed.
It changes over time so that it is zero at , then rises and becomes "1" at time T2, and then falls and becomes zero again at time T3. When the key is pressed (tl=o)
Since the parameter signal is p(t)-0, the musical sound waveform [W2・P(t)+W1[1-p(t)}]=W1
becomes.

Therefore, a waveform W1 having very few harmonic components as shown in FIG. 3A is outputted from the musical waveform generator 4. Subsequently, as time passes and the parameter signal P(t) rises, the component of waveform W1 in the musical sound waveform gradually decreases, and instead, the component of waveform W2, which contains many harmonic components, gradually decreases. It will be added.

For example, when P(t)-0.5, the musical sound waveform [W2・P
(t)+w1{1-p(t)}]-(W1+W2)/2
Thus, a musical sound waveform is obtained in which the waveform W1 and the waveform W2 are synthesized at a ratio of 1:1. Eventually P(t)=1(time T2
), the musical sound waveform [W2・P(t)+W1{1−p
(t)}]=W2. Therefore, the waveform W2 containing many harmonic components as shown in FIG. 3B is generated by the musical waveform generator,
Output from 4. That is, the musical tone generated at this time has the richest tone color for the electronic musical instrument. In addition, as described above, each time tl to T3 of the envelope waveform in FIG. 2A corresponds to the parameter signal p(
t) is set to correspond to each time tl to T3. At time T2, the envelope waveform in FIG. 2A is at the highest level AL. Therefore, the musical tone generated at time T2 has the maximum volume in addition to the richness of tone as described above. Further, as time passes and the parameter signal P(t) falls, the component of the waveform W1 is added to the musical sound waveform instead of gradually decreasing the component of the waveform W2.

For example, when p(t)=0.5, the musical tone waveform is a composite of waveform W1 and waveform W2 at a ratio of 1:1, as in the case described above. Eventually, at time T3, p(t)=o, and the state returns to the state when the key was pressed, so the waveform W2, which contains many harmonic components, is no longer included at all, and the musical sound waveform is only the waveform W1, which has few harmonic components. , and at this point the generation of musical tones ends.

When a connecting tone musical tone is selected, the parameter signal P
(t) changes over time, as shown in FIG. 4B, for example. In this case, since the parameter signal p(t) is maintained at a constant value during the period T3→T4, the musical sound waveform [W2·p(
t)+w1{1-p(t)}] also maintains a constant shape.

Therefore, musical tones of the same tone are generated between time T3 and time T4. At other times, musical tones whose timbre always changes are generated, as in the case of the percussive musical tones described above. Further, since the envelope waveform is maintained at a constant value during the period T3→T4 as shown in FIG. 2B, the volume of the musical tone is also constant during this period. In particular, in the case of the embodiment described above, by providing one parameter signal p(t) that changes over time, a musical sound waveform with few harmonic components is formed when a key is pressed, and then the harmonic components gradually increase. After that, a tone waveform containing fewer harmonic components is formed again.

Therefore, musical tones extremely close to natural musical tones are generated. (Effects of the Invention) As explained above, according to the present invention, the first waveform W1 and the second waveform W2, which have different waveform shapes, can be separated at an arbitrary ratio (
To form a musical sound waveform synthesized by the ratio), the waveform (W2-W1) corresponding to the difference between the two waveforms is multiplied by the parameter signal P, and the resulting waveform (W2-W1)
The first waveform W1 is added to P.

Therefore, since only one parameter generator and multiplier are required to synthesize both waveforms Wl and W2 at an arbitrary ratio, electronic musical instruments are The overall configuration becomes simple and costs are reduced. In particular, the fact that only one expensive digital multiplier is required for synthesis is a significant cost advantage. Further, according to the present invention, the first waveform W1 and the second waveform W2 are
1-P}:P, the amplitude level of the formed tone waveform does not change and remains constant even if the value of the parameter signal P changes, except for changes due to the envelope waveform.

Therefore, it is possible to completely prevent unexpected changes in volume due to changes in timbre of musical tones. Furthermore, by changing the parameter signal P as described above over time, the shape of the musical waveform changes over time, making it possible to generate musical tones whose timbre changes over time, like natural musical tones. , the performance of electronic musical instruments will improve accordingly.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an electronic musical instrument according to the present invention, FIGS. 2A and B are graphs showing examples of envelope waveforms, and FIGS. 3A and B are graphs showing examples of envelope waveforms in the first and second waveform memories. Graph showing examples of stored waveforms, 4th
Figures A and B are graphs showing examples of parameter signals. 1... Keyboard circuit, 2... Frequency information memory, 3... Accumulator, 4... Tone waveform generator, 5... - Multiplier, 6... Envelope waveform generator, 7... Sound system, 21, 22... Waveform memory, 24...
...Subtractor, 26...Parameter generator, 28
...Multiplier, 30...Adder, Wl,
W2... Waveform, P(t)... Parameter signal.

Claims (1)

[Claims] 1. A musical sound waveform is generated by synthesizing a first waveform [W1] and a second waveform [W2] that have a frequency corresponding to the pitch of the musical sound to be generated and have different waveform shapes. A first waveform generation circuit that generates the first waveform [W1], and a waveform corresponding to the difference between the first waveform [W1] and the second waveform [W2]. Waveform [W2-W1
] and a second waveform generating circuit that generates a parameter signal [
P], a multiplier that multiplies the parameter signal [P] by the waveform [W2-W1] generated from the second waveform generation circuit, and an output of this multiplier [(W2 -W1)・P] and the first waveform [W1] generated from the first waveform generation circuit, and output the addition result as a musical sound waveform [W2・P+W1・(1−P)]. An electronic musical instrument comprising an adder. 2. The electronic musical instrument according to claim 1, wherein the parameter generation circuit generates a time-varying parameter signal [p(t)]. 3 The first waveform generation circuit generates the first waveform [W
1], the second waveform generating circuit has a first waveform memory that stores the first waveform memory and reads the first waveform memory using an address signal that advances in accordance with the pitch of the musical tone to be generated; A second waveform memory stores the waveform [W2] of No. 2 and is read out using the address signal, and the output of the first waveform memory is subtracted from the output of the second waveform memory to obtain the waveform [W2]. -W1]. The electronic musical instrument according to claim 1, further comprising a subtracter that outputs the following: -W1].