JPS5917432B2 - Harmonic synthesis electronic musical instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic musical instrument in which a desired tone is obtained by synthesizing five harmonic waves using a digital drawbar.

Conventionally, as a method of harmonic synthesis using an analog drawbar, there is a method in which a tone wheel generates a sine wave as a sound source, and the 10 sine wave outputs are synthesized by operating the drawbar to obtain a desired tone.

The tone generator that generates a sine wave as a sound source has a structure as shown in Figure 1, and when the tone wheel TW placed opposite the pickup coil PC rotates, the tone wheel TW An alternating current voltage proportional to the number of teeth and its rotation speed is induced in the pickup coil PC. Such a tone generator is provided for each harmonic frequency component, and a drawbar is provided corresponding to each tone generator. Drawbar 20
is a pull-out switch, and by pulling the drawbar appropriately, the volume of each frequency component is adjusted, and the sine waveform of each harmonic generated by the tone generator is appropriately synthesized to obtain various tones. . In this case, the output waveform from the tone generator is required to be a perfect sine waveform, but in the case of a tone generator like the one shown in Figure 1, unnecessary components cannot be removed completely and distortion occurs. It is difficult to obtain a large, perfect sinusoidal waveform. In addition, such a tone generator can be used to generate each harmonic frequency.
0 It has the disadvantage that the scale of the musical instrument increases because it has to be provided for every several components. Another method is to use an oscillator to generate harmonics, but this method requires a large number of oscillators and increases the scale of the instrument. Since the oscillator must be in a doubling relationship, precision is required in the adjustment of the oscillator, and the harmonics obtained are limited to eight harmonics at most.0.67 - This invention was made to eliminate the drawbacks of the prior art. The purpose is to perform harmonic synthesis using a method that is completely different from conventional techniques.

That is, the present invention forms an address signal corresponding to a key, and sequentially reads out the sine waveform amplitude value for each harmonic based on the address signal from a storage device that digitally stores the sine waveform of the fundamental wave. , The read sine amplitude value of each harmonic is multiplied by a level control signal set for each harmonic corresponding to the desired timbre for each harmonic,
In a harmonic synthesis electronic musical instrument in which harmonic synthesis is performed by successively accumulating the multiplication values to generate musical tones of a predetermined timbre, the level A plurality of operators each arbitrarily setting a control signal, and a control means for sequentially taking out the level control signal set by each of the operators in synchronization with reading out the sine amplitude value of each of the harmonics. The present invention provides a harmonic synthesis type electronic musical instrument that is configured such that desired various tones can be easily and accurately obtained with a small-scale system. The invention will now be described in detail with reference to embodiments of the accompanying drawings.

FIG. 2 is a block diagram showing the configuration of an embodiment of the electronic musical instrument according to the present invention.

The frequency number storage device 2 stores a numerical value corresponding to the frequency of each pitch, and this numerical value will be referred to as an F number.

When a key is pressed on keyboard switch 1, the F corresponding to that key is pressed.
The number is read from the frequency number storage device 2. F
The value of the number is determined as shown in Table 1, for example. 1st
The table shows the relationship between the frequency Fh and the F number for each pitch from the C note of the sixth octave (C6) to the C note of the seventh octave (C7). In the case of Table 1, the F number is determined to be "1.0000" based on pitch C7 (frequency Fh = 2093.00 Hz), and for other pitches, the frequency ratio to pitch C7 is - One L
The F number was determined based on 08Ω988.

The F number read from the frequency number storage device 2 is input to the address generator 4 through the gate 3.

The gate 3 is opened every predetermined unit time Tx based on the output pulse of the harmonic counter 8. That is, the harmonic counter 8 counts the master clock generated by the master oscillator, and sends a pulse to the gate 3 to open the gate 3 every time this clock pulse is counted by 16 pulses. In this embodiment, since a total of 16 harmonic components from the fundamental wave to the 16th harmonic are synthesized, a hexadecimal counter is used as the harmonic counter 8. Tc and the above unit time Tx
The relationship is TX=16tc. Furthermore, the above unit time theory is determined by the above-mentioned pitch frequency Fh and F number, and the number of sample points M of one period of the sine waveform stored in the sine wave amplitude storage device 5, which will be described later, and Tx-? becomes.

In this implementation FhXM example, M=32 as described later, so Tx
teeth? -14.9 microseconds and O808Nv99 Address generator 4 temporarily stores the value of the F number sent from gate 3 and uses it as master clock period Tc.
Accumulate sequentially according to .

In other words, the cumulative values are F, 2Fl3F...1
The value becomes 6F, and the sine wave amplitude storage device 5 is stored for each accumulated value.
is input. The value F is accumulated 16 times and the accumulated value is 16F.
When this happens, the high frequency counter 8 counts 16, so the gate 3 is opened and a new F number is sent out. Here, the integer parts of the cumulative values F, 2F, .
. . . This is an address for reading out the sine wave sample point amplitude value for each harmonic of the 16th harmonic, and the sine wave sample point amplitude value of each harmonic is read out from the sine wave amplitude storage device 5 every cycle Tc of the master clock. The fundamental wave is sequentially read out according to the address. The time required to read out from the fundamental wave to the 16th harmonic is the unit time Tx described above.
Further, when the gate 3 is opened and a new F number is sent out, the address generator 4 adds the temporarily stored value F and the newly input F number, and then adds the added value 2.
F is newly temporarily stored, and this value 2F is successively accumulated according to the master clock cycle Tc to obtain 2F14F.
...The cumulative value of 32F is sequentially output. The integer part of this accumulated value becomes an address for reading the sine waveform sample point amplitude value of each harmonic in the next unit time Tx.
Now, taking A#6, G6, and C7 sounds as an example, the cumulative value QF of the F number regarding the fundamental wave (q is 1, 2 for each unit time Tx)
, 3, etc.).
Shown in the table. According to Table 2, in order to form one period of the C note, it requires the passage of 32 unit times Tx, that is, the accumulation of the F number 32 times, and in the case of the A#6 note, 36 times. It has been found that in the case of the G6 note, it is necessary to accumulate the F number 43 times, and it has been shown that the lower the tone, the more the number of F numbers accumulated. Further, the accumulated value for each harmonic that is accumulated by the period Tc of the master clock becomes a value NqF for the n (n=1, 2, . . . , 16)th harmonic component. In the sine wave amplitude storage device 5, an accurate sine waveform related to the fundamental wave is digitally stored as 32 sample point amplitude values, and each sample point amplitude value for each harmonic is determined by the accumulation of the F numbers. Value Np
It is read out from this sine wave amplitude storage device 5 using the integer part of F as an address.

Note that the sine waveform stored in the sine wave amplitude storage device 5 does not need to be an exact waveform, and considering the absolute value of the amplitude value of each sample point of the sine waveform, it is possible to store only the first half of one waveform. For example, a sine waveform O~1 (R
It is also possible to divide up to ad) and store the amplitude value of each sample point as binary data.

The sine waveform sample point amplitude values for each harmonic component from the fundamental wave to the 16th harmonic, which are sequentially read out from the sine wave amplitude storage device 5 during a unit time Tx, are stored in the attack day in the harmonic amplitude multiplier 6. The signal is multiplied by the level of each harmonic added to the K envelope. Note that the level of each harmonic is selected depending on the drawn state of the drawbar corresponding to each harmonic in the drawbar device 9. Next, harmonic synthesis using this drawbar will be explained with reference to FIG.

FIG. 3 is a block diagram of one embodiment of the drawbar device 9. The output of the hexadecimal harmonic counter 8 is sent as 4-bit binary data HC to the decoder DE, where it is decoded into 16 signals from the fundamental wave d1 to the 16th harmonic D16.

The 16 signals dl to Dl6, which are the outputs of the decoder DE, are connected to the common terminals S1 to Sl6 of the switches of the drawbars D1 to Dl6, respectively, and only one output line corresponding to the input HC of the decoder DE The output line becomes low level, and the other 15 output lines become high level. Also drawbar D
Since the outputs of D1 to D16 are wired-OR, it is necessary to use the output of the decoder DE from an offset collector. The timing at which a low level is sent to each of the output lines dl to Dl6 is equal to the period Tc of the master clock, and the low level is sent out at intervals of time Tc (from dl to Dl6), for a total of 16 signals. The period at which the process is completed is equal to the unit time Tx. The drawbar is a pull-out switch that adjusts the level of each harmonic.Drawbar D1 is the fundamental wave, D2 is the second harmonic...D
l6 corresponds to the 16th harmonic.

In this example, as shown in detail regarding the drawbar D1, the drawbar state can be selected from 0 dB to -40 dB in 2 dB steps, and when adding the -00 dB state, a total of 22 levels of level adjustment are possible. It is something. For example, when the drawbar is not pulled at all, the common terminal is 0, and when the drawbar is pulled to the maximum, the common terminal is 0.
dB position and the maximum level is obtained at this time. The state of each drawbar D1 to Dl6 is a time T. The signals are sequentially detected in each time division and input to the encoder EN. Drawbar output is 3rd
As partially illustrated in the figure, since the encoder is wired-or, one encoder EN is sufficient regardless of the number of drawbars. The encoder EN converts the level state information detected from each drawbar into binary data,
For example, it is coded as shown in Table 3. The output from encoder EN is decibel-linear converter CV
It becomes an address for reading out the memory contents of the decibel-linear converter CV.

The decibel-linear converter CV linearly converts the decibel scale level detected from each drawbar, and is comprised of a read-only memory (ROM). From the decibel-linear converter CV, the level from the fundamental wave set to each drawbar to the 16th harmonic is sequentially read out in linear quantities as 7-bit binary data, and the output is sent to the attack/decay multiplier 11. The input attack decay envelope data is multiplied. Attack decay envelope data is sent from attack decay device 10 to attack decay multiplier 11 .

Attack decay device 10 includes attack decay control logic (not shown) and attack decay memory (not shown). Before starting the attack, first confirm that keyboard switch 1 is closed.
Detected by Decay control logic circuit. Based on the detected data, the attack decay control logic circuit generates an address for reading data stored in the attack decay memory. The attack decay memory stores the shape of the attack decay envelope digitally. According to the address, data of the attack envelope is read out from the attack decay memory for an appropriate period of time from the time the key is pressed, and this data is sent to the attack decay multiplier 11. It should be noted that the attack decay control logic circuit includes a predetermined timing circuit (not shown) which controls the duration of the attack and decay. When the attack decay control logic circuit detects that the keyboard switch 1 is released, the decay envelope data is read out from the attack decay memory in the same manner as the attack envelope. The signal is sent to multiplier 11. However, there is a decay holding control device that causes the frequency number storage device 2 to continuously output the F number value of the pitch selected by the keyboard switch 1 that has just been opened for a predetermined decay period.
(not shown) is included in the attack decay control logic. In this way, the level of each harmonic corresponding to the state of each drawbar multiplied by the attack decay envelope is repeated in order from the fundamental to the 16th harmonic every master clock period Tc and every unit time Tx, and the attack decay is repeated every unit time Tx. The signal is sent from the multiplier 11 to the harmonic amplitude multiplier 6.

On the other hand, as described above, the sine wave sample point amplitude values of each harmonic from the fundamental wave to the 16th harmonic are read out sequentially from the sine wave amplitude storage device 5 in a time-divided manner every period Tc of the master clock. There is.

Therefore, the timing at which the sine waveform sample point amplitude value of each harmonic and the corresponding level for each harmonic are sent to the harmonic amplitude multiplier 6 is completely coincident. For example, at the same time that the sine wave amplitude is stored in the first cycle Tc, the level state set in the drawbar D1 corresponding to the fundamental wave is multiplied by the attack decay envelope data from the attack decay multiplier 11. The signal is input to a harmonic amplitude multiplier 6, multiplied by the amplitude value of the fundamental wave, and output to an accumulator 12. Next, at period Tc, the second harmonic sine waveform sample point amplitude value and the level corresponding to the setting state of the drawbar D2 are multiplied by the harmonic amplitude multiplier 6 and output to the accumulator 12. Similarly, for each harmonic, the sine waveform sample point amplitude value is multiplied by the level corresponding to the drawbar setting state, and the result is output to the accumulator 12. Accumulator 1
In step 2, all harmonic components are synthesized by successively accumulating the harmonic amplitude multiplication values from the fundamental wave to the 16th harmonic, and a musical tone with a desired timbre according to the settings of drawbars D1 to Dl6 is produced. Form sample point data of the waveform.

That is, the accumulator 12 successively accumulates the output of the harmonic amplitude multiplier 6 for each cycle Tc of the master clock, and when the accumulation from the fundamental wave to the 16th harmonic is completed, the harmonic counter 8 calculates the output of the harmonic amplitude multiplier 6 for each cycle Tc of the master clock. A pulse is sent, and according to this pulse, the accumulator 12 is set, and the accumulated value, that is, the sample point data of the musical waveform in which the timbre has been synthesized, is transferred to the buffer register 1.
Send to 3. The sample point data of this musical waveform is passed through a buffer register 13 to a digital-to-analog converter 14.
After being converted into analog data, it is sent to the audio device 15 and output as audio. Thereafter, each sample point data of the musical tone waveform is outputted every period Tx in the same manner. Although the above description has been made regarding single tones, harmonic synthesis of multiple tones can be easily realized in the same manner as for single tones by using a time division method.

Furthermore, if the level of each harmonic that realizes a specific tone is stored in advance in a read-only memory (hereinafter referred to as ROM), etc., and such a ROM is provided in advance along with the drawbar device 9 for each tone. When producing a tone related to the ROM, the desired tone can be obtained immediately by selecting the ROM without adjusting each drawbar. A device including such a ROM will be referred to as a preset device. An example of this preset device will be explained below.

As an example, read-only memories ROM1, ROM2, and ROM3 store the levels of each harmonic related to three types of tones.
shall be provided.

Using the output HC of the harmonic counter 8 as an address, the level of each harmonic previously stored in this read-only memory is sequentially read out as 5-bit binary data from the fundamental wave to the 16th harmonic, and the ROM1~ The output from any one of the ROMs 3 is sent to a decibel-to-linear converter CV. At this time, the input of the decibel-linear converter CV becomes a wired OR, so ROM1~R
It is necessary to use open collector outputs for the output of OM3 and the output of encoder EN. Operation command signals E1 to E3 are inputted to each ROM from the tone selection switch SS. For example, the common terminal S of the tone selection switch SS
When O is set to ROM, only the signal E1 becomes low level, only ROM is operated, and harmonics are synthesized according to the level of each harmonic stored in ROM1.
A desired tone (for example, if ROM1 corresponds to a flute, the tone of a flute) is emitted from the acoustic device 15. In addition, if the timbre selection switch SS is provided with a drawbar terminal and the decoder DE in the drawbar device 9 is made to send the operation command signal Ed, it is possible to use the ROM for harmonic synthesis.
Alternatively, it becomes possible to select as appropriate whether to use the drawbar. That is, when using a drawbar, the common terminal S of the tone selection switch SS. is set to the terminal Sd, and only the signal Ed is set to low level to operate the decoder DE.
All that is required is to operate the drawbar device 9. In this case, the signal E
The decoder DE operates only when the signal Ed is at a low level, and when the signal Ed is at a high level, all 16 outputs d1 to Dl6 of the decoder DE are at a high level, and the drawbar device 9 does not operate. In this way, by combining the drawbar device and the preset device and using them as appropriate, it is possible to perform a variety of performances. Furthermore, it is not limited to a storage device ROM that stores the level of each harmonic for each tone, but may also be a random access memory (hereinafter referred to as RAM).
When a RAM is used, it becomes possible to appropriately store the level states set for each of the drawbars D1 to D16. To give some specific examples regarding the scale of the electronic musical instrument according to the present invention, the decoder DE in the drawbar device is composed of about 2 IC elements, the encoder EN is composed of about 10 IC elements, and a decibel-linear converter. The CV is composed of one IC element and is an extremely small-scale device.

Further, in the above description, a drawer type drawbar was described as an operator for synthesizing each harmonic component, but the drawer type drawbar is not limited to this, and other types such as a rotary switch may also be used. As described above, according to the present invention, since the harmonics are generated digitally, an accurate sine waveform can be obtained, almost no distortion of the sound occurs, and each of the 16 types of harmonics is Since the level can be adjusted in stages, a wide variety of combinations of harmonics can be realized, and one oscillator is sufficient, and the use of an IC makes the device extremely small-scale.

In this way, it is possible to create musical tones with an almost infinite variety of different tones by operating a plurality of operators in arbitrary combinations, and it is also possible to change the tone over time by operating each operator appropriately during a performance. Any desired tone can be easily and accurately obtained with a small system.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of a tone generator for generating sine waves in a conventional drawbar system, FIG. 2 is a block diagram showing the configuration of an embodiment of an electronic musical instrument according to the present invention, and FIG. FIG. 2 is a block diagram showing one embodiment of the graphics pad drawer device 9; 1... Keyboard switch, 2... Frequency number storage device, 3... Gate, 4...
Address generator, 5...Sine wave amplitude storage device,
6...Harmonic amplitude multiplier, 7...Master oscillator, 8-...Harmonic counter, 9...
...Drawbar device, 10...Attack, Decay device, 11...Attack Decay multiplier, 12...Accumulator, 13... Buffer register, 14...Digital-analog converter, 15...Audio device, DE...Decoder, D1-Dl6...Drawbar, EN...・
...Encoder, CV... Decibel-linear converter.

Claims (1)

[Claims] 1. Form an address signal corresponding to the key, sequentially read out the sine waveform amplitude value for each harmonic based on the address signal from a storage device that digitally stores the sine waveform of the fundamental wave, and read out the sine waveform amplitude value for each harmonic. Harmonic synthesis is performed by multiplying the sine amplitude value of each harmonic by a level control signal set for each harmonic corresponding to the desired timbre for each harmonic, and successively accumulating the multiplied values. A harmonic synthesis type electronic musical instrument configured to perform the above-mentioned harmonics and generate a musical tone of a predetermined timbre, a plurality of operators provided corresponding to each of the harmonics and arbitrarily setting the level control signal, respectively;
A harmonic synthesis type electronic musical instrument comprising: a control means for sequentially extracting the level control signals set by the respective operators in synchronization with reading out the sine amplitude values of the respective harmonics.