JPS6142279B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an electronic musical instrument using a waveform memory reading method.

The waveform memory read-out electronic musical instrument according to the present invention uses a random access memory (RAM) as the waveform memory, and is characterized in that it is used as the waveform memory without initially clearing the random access memory.

That is, in an electronic musical instrument using a waveform memory reading method using a random access memory, the random access memory is initially cleared when the power is turned on, and in this state, a desired musical sound waveform (sound source waveform) to be generated is written (for example, when a natural musical instrument is used). The musical instrument sounds are input through a microphone, etc., and this is converted into a digital signal and stored.) This is then read out to generate musical sounds.

However, in the present invention, a musical tone with a new tone can be created by reading out a random white noise-like waveform that is naturally written into the random access memory without initially clearing the memory when power is applied to the random access memory. Its purpose is to occur.

The electronic musical instrument of the present invention includes an address signal generator that generates a read address signal, and a random access memory that is read by the address signal, and that is written to the memory when power is applied to the random access memory. It is constructed so that a random waveform is read out in accordance with the address signal and a musical tone is generated.

The present invention will be described in more detail below with reference to embodiments shown in the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, in which a keyboard circuit 1 outputs a key code KC corresponding to a pressed key, and this key code KC is input to an address signal generator 2. Address signal generator 2 receives key code KC and outputs address signal AD corresponding to the pressed key, which is input to random access memory 3. random access memory 3
A random waveform (a white noise-like waveform) is automatically written to when the electronic musical instrument is powered on, and the amplitude value of each sample point of this waveform is read out as a musical sound waveform MW in accordance with the address signal AD. This musical sound waveform MW is a key-on signal generated from the keyboard circuit 1 when a key is pressed in the multiplier 5.
After being multiplied by the envelope waveform EV output from the envelope waveform generator 4 which operates in response to KON, the sound system 6 produces a musical tone.

In this first embodiment, if a power on/off switch is provided only for the random access memory 3, the waveform stored in the random access memory 3 can be easily changed.

According to this first embodiment, a white noise-like random waveform containing a large amount of high frequency components is stored in the random access memory 3. Therefore, the resulting musical tone contains a large number of overtone components. For example, if the number of sample points included in one wave stored in the random access memory 3 is N, a large amount of overtone components of N/2 or less will be included, producing a musical sound that sounds as if it has been passed through a filter with a high Q value. can do.

Furthermore, according to the present invention, since a white noise-like random waveform is stored in the random access memory 3, new musical tones can be created.
By adding such a function as one of the functions of an electronic musical instrument, the value of the electronic musical instrument increases.

FIG. 2 shows a first example of the address signal generator 2 of the embodiment shown in FIG. 1, and each address of the frequency information memory 21 has frequency information corresponding to the pitch of each key. is stored, and frequency information F having a large value is stored for a key with a high pitch, and frequency information F having a small value is stored for a key having a low pitch. The frequency information memory 21 stores the key code KC output from the keyboard circuit 1.
is received as an address signal and outputs frequency information F corresponding to the pressed key, and this frequency information F is sequentially accumulated in an accumulator 22 according to the clock pulse φ and output as an accumulated value qF. This cumulative value
qF is input to the random access memory 3 as an address signal AD.

According to the address signal generator 2 shown in FIG. 2, the frequency information F corresponding to the pitch of each key is stored in the frequency information memory 21, so when a key with a high pitch is pressed, the third As shown in Figure A, an address signal AD with a short repetition period is output, and when a key with a low pitch is pressed, an address signal AD with a long repetition period is output as shown in Figure 3B.
As a result, the musical sound waveform MW corresponding to the pitch of the pressed key is read out from the random access memory 3.

FIG. 4 shows a second example of the address signal generator 2 of the embodiment shown in FIG. 1, in which frequency information F' corresponding to each key is stored in each address of the frequency information memory 21. ing. This frequency information memory 21 receives the key code KC output from the keyboard circuit 1 as an address signal, outputs frequency information F' corresponding to the pressed key, and outputs frequency information F' corresponding to the pressed key.
F' is input to the input terminal A of the comparator 25. On the other hand, the output of the oscillator 23 is input to the counting input terminal I of the counter 24, and the counter 24 counts the clock pulses output from the oscillator 23, and the counted value K is used as the address signal AD and is input to the comparator 25. It is input to terminal B. Comparator 25 compares the value of frequency information F and count value K, and outputs a match signal EQ from output terminal E when count value K of counter 24 becomes equal to the value of frequency information F. This coincidence signal EQ is input to the clear terminal C of the counter 24, whereby the counter 24 is periodically cleared.

That is, according to the address signal generator 2 shown in FIG. 4, the count value K of the counter 24 is the address signal AD.
This counter 24 is periodically cleared in accordance with the frequency information F' read out in response to the pressed key. Here, frequency information memory 2
1, frequency information F' with a small value is stored for a key with a high pitch, and frequency information F with a large value is stored for a key with a low pitch. Therefore, when a key with a high pitch is pressed, a waveform with a short repetition period like waveform a in Fig. 5 is output as the address signal AD, and when a key with a low pitch is pressed, a waveform with a short repetition period is output as the address signal AD. A waveform with a long repetition period, such as waveform b in FIG. 5, is output as the address signal AD. Therefore, the address signal generator 2 shown in FIG.
According to the above, when a key with a high pitch is pressed, each waveform amplitude value stored in the first half of the address group of the random access memory 3 is read out at a high repetition rate, and when a key with a low pitch is pressed. When the key is pressed, each waveform amplitude value permanently stored in a wide address range including the second half of the address group of the random access memory 3 is read out at a low repetition cycle.

In FIG. 4, the values of each frequency information F' stored in the frequency information memory 21 are all changed to 1/2, and in addition, the counter 24 is replaced with an up-down counter. Furthermore, this up-down counter 2
4 is set to the up mode when the counted value becomes "0", and set to the down mode when the counted value becomes equal to the frequency information F. As a result, the count value of the up-down counter 24 increases and decreases alternately, so that a folded (triangular wave) address signal is formed. Therefore,
According to this modified embodiment, the random access memory 3 can be configured with a memory having a small memory size.

Furthermore, when using the address signal generator 2 shown in FIG. 4, the address range read out in the random access memory 3 changes depending on the pitch of the pressed key, so the timbre of the generated musical tone changes depending on the pitch. This causes the inconvenience of This sends an address signal every time the pitch of the pressed key goes down an octave.
The AD change range doubles, and as a result, the number of samples that make up one period of the musical sound waveform read from the random access memory 3 doubles, and the overtone components included in the musical sound waveform also double. It is from. In order to prevent such a situation, for example, the lower bit of the address signal AD, which is applied to the random access memory 3 every time the octave decreases, may be held at a logical value of "0".
That is, when a key belonging to the highest octave is pressed, all bits of the address signal AD are input as they are to the random access memory 3, and when a key belonging to an octave below the highest octave is pressed. is the address signal input to memory 3
The lowest bit of AD is forcibly held to the logical value "0", and in the same way, when a key belonging to an octave n below the highest octave is pressed, all of the lower n bits of address signal AD are forced. It is configured so that it is held at a logical value of “0”. By doing this, the interval between changes in the address signal AD input to the random access memory 3 (the time interval for moving from one address to the next) is doubled every time the octave to which the pressed key belongs decreases by one octave. Therefore, the number of samples constituting one period of the tone waveform read from the random access memory 3 is the same regardless of the octave.
This can prevent the timbre of the generated musical sound from changing depending on the octave.

FIG. 6 shows a third example of the address signal generator 2 in the embodiment shown in FIG. As shown in FIG. 6, only the note code NC of the key code KC output from the keyboard circuit 1 is input to the frequency information memory 21, and the octave code OC is input to the frequency information memory 21.
is input to the selection command signal input terminal S of the selector 29. The frequency information memory 21 stores frequency information corresponding to each of the 12 note names in the highest octave.
F″ is memorized and the note code NC of the key pressed
Frequency information F'' corresponding to the frequency information F'' is read out. This frequency information F'' is input to the input terminal A of the comparator 25. Furthermore, the clock pulse _φ1 outputted from the oscillator 23 is halved by the flip-flop 26.
The frequency is divided and output as a clock pulse _φ2 .
Similarly, the clock pulse φ is the flip-flop 2
The frequency of the clock pulse _φ1 is divided by _1/4 by the flip-flops 26, 27, and 28 and output as a clock pulse _φ4 . These clock pulses φ ₁ to _{φ 4} are input to input terminals I ₁ to _{I 4} of the selector 29, respectively, as shown.
The selector 29 receives the octave code OC at its selection command signal input terminal S, and selects one of the clock pulses φ ₁ to φ ₄ inputted to each input terminal I ₁ to I ₄ according to the octave code OC. and output. The clock pulse φ _S (any one of φ ₁ to _{φ 4} ) selected and outputted by the selector 29 is input to the counting input terminal I of the counter 24, where it is sequentially counted. This count value K' is used as the address signal AD, and the comparator 2
It is input to input terminal B of No.5.

The comparator 25 compares the value of the frequency information F'' and the count value K', and outputs a coincidence signal EQ' from the output terminal E when the count value K' of the counter 24 becomes equal to the value of the frequency information F''. . This coincidence signal EQ' is input to the clear terminal C of the counter 24, whereby the counter 24 is periodically cleared.

According to this third embodiment, the clock pulse φ
One of the clock pulses ₁ to _.phi.4 is selected according to the octave code OC of the pressed key. For example, when a key belonging to the highest octave is pressed, the clock pulse φ ₁ with the highest frequency among the clock pulses φ ₁ to _{φ 4} is selected, and this is inputted to the counting input terminal I of the counter 24 as the clock pulse φ _S. . Therefore, the counter 24 receives the highest clock pulse φ _S (φ ₄ ) of this frequency.
is counted, and each time this counted value K'' matches the frequency information F'', it is cleared by a coincidence signal EQ'. That is, when the key belonging to the highest octave is pressed, the counter 24 is cleared at the earliest cycle;
As a result, the read address signal AD (count value) corresponding to the pressed key pitch belonging to the highest octave is
K′) is output. Similarly, when the key belonging to the lowest octave is pressed, the lowest frequency clock pulse _φ4 is selected and counted by the counter 24. In this case, the counter 24 is cleared at the slowest cycle, thereby outputting the read address signal AD (count value K') corresponding to the pitch of the pressed key belonging to the lowest octave.

FIG. 7 is a block diagram showing a second embodiment of the present invention, in which the same parts as in the first embodiment are given the same reference numerals and their explanation will be omitted. Note that the random access memory 3 shown in FIG. 7 has a larger number of addresses than the random access memory 3 shown in FIG.
1, one with a large modulus is used. This is because, as will be described below, the embodiment shown in FIG. 7 generates so-called sound effects, and the sound effects are generally longer than the period of sounding the musical tone associated with the key pressing operation.

In FIG. 7, the clock pulse φ' output from the oscillator 30 is input to the count input terminal I of the counter 31, and the count value K'' is input to the random access memory 3 as the read address signal AD. Each waveform amplitude value (white noise-like waveform) stored in the memory 3 is read out sequentially.According to this second embodiment, a white noise-like waveform is output in accordance with the counting operation of the counter 31. , it is possible to generate so-called musical sounds such as cymbal sounds.
Note that if the oscillator 30 is a variable oscillator, the pitch of the generated sound effect can be freely adjusted.

As is clear from the above description, according to the present invention, new musical tones can be created because a random waveform similar to white noise stored in a random access memory is read out, and such a function can be added to an electronic musical instrument. By doing so, you can increase the value of your electronic musical instrument.

[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 first example of the address signal generator 2 in the embodiment shown in FIG.
3A and 3B are waveform diagrams showing examples of address signals output by the address signal generator shown in FIG. 2, and FIG. 5 is a waveform diagram showing an example of the address signal output by the address signal generator shown in FIG. 4, and FIG. 6 is a block diagram showing an example of the address signal generator shown in FIG. 1. FIG. 7 is a block diagram showing a second embodiment of the present invention. 1...Keyboard circuit, 2...Address signal generator,
3... Random access memory, 4... Envelope waveform generator, 5... Multiplier, 6... Sound system, 21... Frequency information memory, 22...
Accumulator, 23, 30... Oscillator, 24, 31...
Counter, 25... Comparator, 26, 27, 28...
...flipflop, 29...selector.

Claims (1)

[Claims] 1. An address signal generator that generates an address signal, and a random access memory that is read out by the address signal, and that writes data to the memory when power is applied to the random access memory. An electronic musical instrument that generates musical tones by reading out random waveforms according to the address signal. 2. The address signal generator includes a frequency information memory that stores frequency information corresponding to each key and outputs frequency information corresponding to a pressed key, and a frequency information memory that counts predetermined clock pulses and outputs the counted value as the address signal. Claim 1 comprising: a counter that outputs the frequency information and the counted value, and a comparator that receives the frequency information and the counted value and outputs a coincidence signal when the two become equal, thereby clearing the counter. Electronic musical instruments listed. 3. The address signal generator is a selector that divides each key into a plurality of blocks and selects and outputs one of the plurality of clock pulses having a predetermined frequency ratio to each other according to a block code indicating the block to which the pressed key belongs. a frequency information memory that outputs frequency information according to a note code indicating the number of the key in the block; and a counter that counts clock pulses output from the selector and outputs the counted value as the address signal. , a comparator that compares the counted value of the counter with frequency information output from a frequency information memory, and outputs a match signal when the two values are equal, thereby resetting the counter. An electronic musical instrument according to item 1 of the scope of . 4. The electronic musical instrument according to claim 1, wherein the address signal generator comprises an oscillator and a counter that counts clock pulses output from the oscillator.