JPS607800B2 - electronic musical instruments - Google Patents

Description

[Detailed Description of the Invention] This invention generates a fundamental wave (fundamental tone) and its harmonic components (overtones), weights the fundamental wave and harmonic components by their corresponding amplitude coefficients, and then synthesizes them. The present invention relates to an electronic musical instrument that uses harmonic synthesis to form musical tones, and particularly relates to an electronic musical instrument that can obtain natural and rich musical tones by temporally changing the amplitude coefficient.

A. Description of the Prior Art Some harmonic synthesis type electronic musical instruments obtain musical tones by sequentially calculating amplitude values at successive sample points of a musical sound waveform based on the m formula.

(q=1, 2,......) where 1, Xo (qR)... Waveform amplitude value at sequential sample points of musical sound waveform.

R: A numerical value proportional to the frequency (pitch) of the generated musical tone (hereinafter referred to as a frequency number).

n...Represents the order of harmonic components including the fundamental wave, where n=1 is the fundamental wave (fundamental tone), n=2 is the second harmonic (second overtone), and n=3 is the third harmonic. (3rd overtone) Corresponds to...

Cn: Amplitude coefficient (Fourier coefficient) for harmonic components of each order.

N...Number of sequential sample points of musical sound waveform W
...Total number of harmonics to be synthesized at sequential sample points.

There is a relationship of W=N/2.

In addition, in the following explanation, A wave includes a fundamental wave. The fundamental wave is the first harmonic. Ru.

An electronic musical instrument based on this harmonic synthesis method is configured as shown in FIG. 1, for example.

In the figure, reference numeral 1 denotes a key switch circuit provided in the keyboard section, which has a key switch corresponding to each key of the keyboard section. When a certain key is pressed, the corresponding key switch operates, and its output line The circuit is configured to output a signal with a logical value of "1". This key switch circuit 1 has a built-in single-tone priority circuit, so that when two or more key switches operate at the same time, a "1" signal is output only to the output line corresponding to the key switch with the highest priority. It has become. The output line corresponding to each key switch of the key switch circuit 1 is connected to the input side of a frequency number memory 2 in which a frequency number R corresponding to the pitch of each key is stored. Then, the frequency number R corresponding to the pitch of the key is read out from the frequency number memory 2, addressed by the output of the key switch circuit 1. On the other hand, the clock oscillator 3 outputs a wide clock pulse of a constant period, and this clock pulse is frequency-divided by W in the counter 4, so that the calculation interval timing signal becomes.

In this case, "W" is the total number of harmonics to be synthesized. For example, when synthesizing up to the 16th harmonic, "W=1
6". The calculation interval timing signal tx created in this way is supplied to the gate 5. This gate 5 opens every time the calculation interval timing signal is supplied, and supplies the frequency number R output from the frequency number memory 2 to the pitch interval adder 6. The pitch interval adder 6 accumulates the frequency number R each time it is supplied via the gate 5 (that is, each time the calculation interval timing signal tx is generated) and calculates IR, 2R, . The cumulative value qR that increases as 3R... is output. Then, the adder 6 calculates the accumulated value qR
When exceeds the modulo N of the adder 6, an overflow occurs, and thereafter, the same accumulation operation is performed again every time the calculation interval timing signal 戊 is generated. In this way, the accumulated value qR, which changes every time the calculation interval timing signal 〇 occurs, is supplied to the harmonic interval adder 8 via the gate 7 which is gated by the clock pulse tc. In this case, the calculation interval timing signal for the clock pulse is W.
Since it has twice the frequency, the gate 7 is opened W times during one period of the calculation interval timing signal 戊. As a result, the harmonic section adder 8 sequentially adds the accumulated value qR output from the gate 7 every time a wide clock pulse occurs, and outputs the accumulated value nqR. When the adder 8 completes the accumulation W times, it is reset by the calculation interval timing signal 戊 and performs the same operation thereafter. Therefore, this harmonic interval adder 8 is calculated by adding 1 of the calculation interval timing signals.
This means that an accumulated value nqR (n=1, 2, 3, . . ., W) is generated that increases sequentially in accordance with the clock pulse during the period. This accumulated value nqR is decoded by the memory address decoder 9, and the decoded output is supplied as a sine function memory address signal in which sequential sample point amplitude values of one period of the sine wave waveform are stored in each address. , reads out the sine amplitude value Sin 'W town R from the memory 0. As is clear from the above explanation,
The cumulative value nqR of the pitch section adder 6 indicates the sequential sample points at which musical waveform amplitude should be calculated, and the cumulative value nqR of the harmonic section adder 8 indicates the n-th harmonic at the sequential sample point qR currently being calculated. It represents the phase of the wave. As a result, the sine amplitude value Sin/W of each harmonic (including the fundamental wave) at the sample point qR is stored from the sine function memory 10.
nqR (n=1, 2...W) are sequentially generated in the order of fundamental wave (first harmonic), second harmonic,...W harmonic. In this case, the sequential sample points of the musical sound waveform to be calculated shift sequentially every time the calculation interval timing signal is generated, but which sequential sample point to shift to next is determined by the frequency number R. This frequency number R is proportional to the pitch of the operating key. Therefore, from the sine function memory 10, the sine amplitude value (Sinm'WnqR
) are generated sequentially in a time-sharing manner. On the other hand, the memory address control device 11 is composed of a modulo counter, which sequentially counts clock pulses tc in synchronization with the counter 4 and stores the count value in the harmonic coefficient memory 1.
2 as an address signal n. The harmonic coefficient memory 12 stores at each address a harmonic amplitude coefficient Cn corresponding to the optimum amplitude value of each harmonic in order to obtain a desired musical timbre. When an address signal n (indicating the harmonic order) that changes sequentially in synchronization with is supplied, harmonic amplitude coefficients Cn that set the amplitude values of each harmonic stored in each address are sequentially read out. This harmonic amplitude coefficient C
n is output to the harmonic amplitude multiplier 13. The harmonic amplitude multiplier 13 receives the sine amplitude value Sin of each harmonic, which is sequentially read out from the sine function memory 10 in a time-sharing manner for each sample point.
m'WnqR and the harmonic amplitude coefficient Cn set for each harmonic are multiplied and the multiplied value Fn=CnSinm/Wn
qR is supplied to accumulator 14. In this case, since the memory address control device 11' is synchronized with the harmonic interval adder 8, the harmonic amplitude coefficient Cn read out sequentially for each harmonic is multiplied by the corresponding harmonic sine amplitude value Sinm/WnqR. , thereby setting the amplitude value Fn for each harmonic. The accumulator 14 sequentially accumulates the amplitude value Fn of each harmonic output from the harmonic amplitude multiplier 13. Then, when the calculation interval timing signal is generated, the gate 15 is opened and the accumulated value of the accumulator 14 (representing the amplitude value at a certain sequential sample point of the musical sound waveform) is D-A.
At the same time as output to the converter 16, the accumulator 14 is reset and performs the same accumulation operation as described above again in order to calculate the amplitude value at the next sequential sample point. Therefore, the D-A converter 16 receives amplitude values (digital signals) at sequential sample points of a musical sound waveform with a period corresponding to the pitch of the pressed key and a waveform shape set by each harmonic amplitude coefficient Cn. The calculation interval timing signal tx is input every time the calculation interval timing signal tx is generated, and by converting this digital amplitude value into an analog signal and supplying it to the sound system 17, the pitch corresponding to the pressed key and the harmonic coefficient memory 12 A musical tone having a tone corresponding to the harmonic amplitude coefficient Cn stored in is generated. On the other hand, the amplitude envelope is applied to the generated musical tone in the following manner.

That is, the sound system 17 is provided with an envelope waveform generator that starts operating in response to the key-on signal KOM output from the key switch circuit 1 when any key is pressed. The output envelope waveform is multiplied by the musical tone signal to impart amplitude envelopes such as attack, sustain, and decay to the generated musical tone. Incidentally, since an electronic musical instrument having such a structure is disclosed in Japanese Patent Application Laid-open No. 48-90217, a detailed explanation of the structure and operation of each part thereof will be omitted. B. Disadvantages of the follow-up technology As is clear from the above explanation, the conventional electronic musical instrument using the harmonic synthesis method described above generates harmonics at a frequency corresponding to the pitch of the pressed key from the time the musical tone is generated to the end. A musical tone is generated by adding a volume envelope to a musical waveform of a tone set by a harmonic amplitude coefficient Cn stored in a coefficient memory.

Therefore, the amplitude of this musical tone only changes due to envelope control, and the waveform shape is the same repeatedly from the time the musical tone is generated to the end, and as a result, the timbre of the generated musical tone is always the same and changes. It becomes something you don't do.
However, in general, the sound produced by a natural musical instrument changes its original color (waveform shape) from the beginning to the end.
There are subtle changes in the color, resulting in a natural, rich blue. Therefore, the above-mentioned conventional harmonic synthesis electronic musical instruments have the disadvantage that the generated musical tones do not have the richness of natural musical instruments, resulting in extremely monotonous performance sounds.

C. Features of the Invention The present invention was made in view of the above-mentioned drawbacks of the conventional harmonic synthesis electronic musical instruments, and it is possible to set the amplitude coefficients for setting the amplitudes of the fundamental wave component and its harmonic components using a simple configuration. The purpose of the present invention is to provide an electronic musical instrument that can produce natural and rich musical tones by changing the amplitude coefficients for each harmonic component in a manner that changes over time and in a related manner. do.

Therefore, in the present invention, a first function waveform is generated as the amplitude coefficient of the fundamental wave component, and a second function waveform that changes over time in a manner different from this is generated, and a constant corresponding to the harmonic component and this waveform are generated. The amplitude coefficient for the harmonic component is obtained by calculating the second function waveform.

Hereinafter, the electronic musical instrument according to the present invention will be explained in detail using the drawings.

D Description of Embodiment '1' Configuration Description FIG. 2 is a block diagram showing an embodiment of the electronic musical instrument according to the present invention, and the same parts as in FIG. 1 are designated by the same symbols.

In the same figure, 18a is a function waveform generator for the fundamental wave provided for the fundamental wave, and this function waveform generator 18
The waveform shape, generation speed, etc. of the function waveform value EV,(t) (amplitude value changes over time) outputted from a is variably set by the parameter setting device 25a. 18b is a function generator for harmonics provided corresponding to harmonic components other than the fundamental wave, and the function waveform value EVm(t) (amplitude value changes over time) output from this function generator 18b. The waveform shape, generation speed, etc. are variably set by the parameter setter 25b.

As will be described later, the function waveform value EV,(t) generated from the function waveform generator 18a becomes an amplitude coefficient for the fundamental wave, and the function waveform value EV,(t) generated from the function waveform generator 18b Based on this, amplitude coefficients for harmonics excluding the fundamental wave are formed. The internal memories of these function generators 18a and 18b sequentially store different digital values (or analog values) based on desired function waveforms. In this case, the function waveform generator 18b for harmonics has a function waveform amplitude value EV having a negative amplitude value.
, (t) are stored such that negative digital values (or analog values) are obtained. 22 is a function waveform value EV output from the function waveform generator 18b for harmonics, and a function waveform value EV for each harmonic is obtained by multiplying (t) by a constant Dn that is different for each harmonic using a multiplier 23. This constant memory 22 stores a constant Dn for obtaining (t)×Dn, and this constant memory 22 counts the width of the clock pulse of a constant period output from the clock oscillator 3 and outputs each harmonic component. Enable signal n, ~ corresponding to the order of
Enable signal n from counter 9 sending out n,6
Addressed by 2 to n·6.

(In this example, the total number of harmonics to be synthesized is up to the 18th harmonic including the fundamental wave.) 24 is the function waveform value EV, (t
) and the function waveform value EV, (
This is a selector that inputs t) and Dn, selects and outputs one of them, and outputs the enable signal n from the counter 19.
, is supplied as a selection control signal, and when the enable signal n, is generated, the function waveform value EV,(t) which is the A input is selected and output, and the enable signal n,
is not generated, the function waveform value EV which is the B input
, (t)·Dn is selected and output.

This is a one-shot circuit that inputs the key-on signal KON of the two-way key switch circuit 1 and outputs a narrow pulse in synchronization with the rising edge of the key-on signal KON. The function waveform generators 18a and 18b start operating.

Note that the function waveform generators 8a and 18b are described as "function waveform generators for electronic musical instruments" in, for example, the well-known Japanese Patent Laid-Open Publication No. 10271/1982, but they are not suitable for generating various function waveforms with the current values as targets. It is possible to use a combination of arithmetic circuits by asymptotic to the value.

In this case, the parameter setters 25a and 25b set target values and the like. Alternatively, one as shown in FIG. 3 can also be used.

In FIG. 3, 26 is a one-shot circuit 20 when a key is pressed.
The pulse oscillator 28 is reset at the rising edge of a narrow pulse generated from the pulse oscillator 28, and thereafter the output pulses of the low frequency pulse oscillator 28 given via the AND circuit 27 are counted until the count value reaches a constant value of all "1"s. For example, an N-bit counter that performs a counting operation and outputs count signals CP, ~CPN; 29 is a count signal CF, ~CPN;
This is an AND circuit that is established when the count value of the counter 26 reaches a certain value based on the CPN.
The output of 9 is inverted by an inverter 30' and becomes an inhibit input of the AND circuit 27. Therefore, when the count value of the counter 26 reaches a certain value, the fund circuit 27
is not established, and the supply of low frequency pulses to the counter 26 is stopped, and accordingly, the counting operation of the counter 26 is also stopped. 1' is a memory in which function waveform values of different values are sequentially stored in each address as a digital value (or analog value) based on a desired function waveform, and the count signal CP, which is output from the counter 26; The stored contents are sequentially addressed and read out by the CPN, and the readout output (multiple bits) of each address is a function waveform value EV, (
t).

Therefore, when a narrow pulse is applied from the one-shot circuit 20 to the function generator 18a (18b) by a key press operation, the counter 26 starts counting operation by the low frequency pulse output from the pulse generator 28. The function waveform value EV,(t) stored in the memory 31 is read out by the count signals CP, ~CPN of the counter 26, and this readout output EV,(t) is a function corresponding to the first harmonic (fundamental wave). Output as a waveform value. ■Operation description In the electronic musical instrument that has been developed in this way, when a certain key on the keyboard is pressed, the corresponding key switch operates and the corresponding output line ``1'' signal of the key switch circuit 1 is output. Ru.

In this case, since the key switch circuit 1 has a built-in single note priority circuit, even if a plurality of keys are pressed at the same time, a "1" signal is output only to the output line with a high priority. The output signal of the key switch circuit 1 addresses the frequency number memory 2, reads out the frequency number R corresponding to the pitch of the pressed key, and outputs the readout signal. This frequency number R is supplied to the pitch interval adder 6 via the gate 5 which is opened by the calculation interval timing signal wide.

The pitch interval adder 6 sequentially adds the frequency numbers R supplied each time the calculation interval timing signal wide occurs, and calculates the cumulative value q.
Output R. The accumulated value qR is supplied to a harmonic section adder 8 via a gate 7 which is opened in response to a clock pulse, and this harmonic section adder 8 converts the accumulated value qR into one of the calculation section timing signals tx. Sequentially add lqR, phantom R, chikuR, etc. at the timing of clock pulse tC within the cycle, and specify the phase of the sine amplitude value at the relevant sample point (qR) of each harmonic (including the fundamental wave). A cumulative value Asahi R is generated.

After the accumulated value nqR is decoded in the memory address decoder 9, the sine function memory 0 is addressed and the sine amplitude value Sintake/WnqR of each harmonic is read out in a time-division manner. This operation is similarly performed every time the calculation interval timing signal is generated, corresponding to sequential sample points of the musical sound waveform corresponding to the pressed key pitch. On the other hand, the function waveform generators 18a and 18b are started to operate by a narrow pulse synchronized with the rise of the key-on signal KON when a key is pressed, which is output from the one-shot circuit 20, and the selector 24 is set to select A by the enable signal n. Then, the function waveform value EV,(t) output from the function waveform generator 18a for the fundamental wave becomes the fundamental wave (
The first harmonic) is output as an amplitude coefficient C,(t) to be multiplied by the sine amplifier Sinm/W1·qR.

Therefore, in the harmonic amplitude multiplier 13, the sine amplitude value Sin t/W1·qR of the fundamental wave is multiplied by the corresponding amplitude coefficient C, (t)=EV, (t), and the multiplied value Fn ' is applied to an accumulator 14 which sequentially accumulates each harmonic component at a sample point. Next, when the enable signal peak is output and the selector 24 becomes select B, the function waveform output from the harmonic function waveform generator 18b. Constant D2 read from constant memory 22 addressed by EVm(t) and enable signal n2
, that is, the output EVm(t)・D of the multiplier 23
2 is the amplitude coefficient C2(t) to be multiplied by the sine amplitude value Sin/W2·qR of the second harmonic through this selector 24.
=EVm(t)·D2.

This kind of operation generates the third harmonic, fourth harmonic...the first harmonic.
The same process is also performed for the 6th harmonic, and output to the harmonic amplitude multiplier 13 as an amplitude coefficient Cn(t) for each harmonic.

In the electronic musical instrument configured in this way, the amplitude coefficient Cnt for the fundamental wave and its harmonics in the function generators 18a and 18b can be set independently, and the function generator 1
Since the function waveforms output from 8a and 18b and their operating speeds can be independently and freely set using the parameter setters 25a and 25b, harmonics can be synthesized while making the most of the characteristics of the fundamental wave.

Furthermore, the amplitude coefficient C2t~ for each harmonic except the fundamental wave
CC, 6 is formed by multiplying the function waveform generated from the function generator 18b by a constant Dn for each harmonic, so that the harmonics are related to each other. Therefore, it is possible to obtain a natural and rich musical tone that is similar to a natural musical instrument whose timbre changes over time while making the most of the characteristics of the fundamental wave. G. Effects of the Invention As explained above, the electronic musical instrument of the invention has a simple configuration because it only requires one harmonic function generator in addition to the fundamental wave function generator. Yes, costs can be reduced.

In addition, since it is possible to freely set each function waveform for the fundamental wave and harmonics output from each function generator and its operating speed, it is possible to make the most of the characteristics of the fundamental wave. Can synthesize harmonics.

Furthermore, since the amplitude coefficient for each harmonic is formed by calculating the function waveform for the harmonic and the constant Dn for each harmonic,
Each harmonic is related to each other. Therefore, while making the most of the characteristics of the fundamental wave, it is possible to obtain a distinctive and rich musical tone similar to that of a natural musical instrument whose timbre changes over time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional electronic musical instrument using a harmonic synthesis method, FIG. 2 is a block diagram showing an embodiment of an electronic musical instrument according to the present invention, and FIG. 3 is a function generator used in the present invention. It is a block diagram showing an example. 1... Key switch circuit, 2... Frequency number memory, 3... Clock oscillator, 4, 19
, 26... Counter, 5, 7, 15, 32... Gate,
6... Pitch section adder, 8... Harmonic section adder, 9... Memory address decoder, 10...
Sine function memory, 13...harmonic amplitude multiplier,
14...accumulator, 16...DA converter,
17....・Sound system, 18a, 18b・
...Function generator, 20...One-shot circuit, 2
2... Constant memory, 23... Multiplier, 24
...Selector, 25a, 25b...Parameter setting device. Figure 3 Figure 1 Figure 2

Claims (1)

[Claims] 1. A harmonic synthesis method that generates a fundamental wave component and its multiple harmonic components that make up a musical tone, weights the amplitude of each component by its corresponding amplitude coefficient, and then adds and synthesizes them to form a musical tone. In the electronic musical instrument, first function waveform generating means is provided corresponding to the fundamental wave component and generates a time-varying first function waveform as an amplitude coefficient for the fundamental wave component; a second function waveform generating means that is provided correspondingly and generates a second function waveform that changes over time in a manner different from the first function waveform, and a predetermined constant that corresponds to each of the harmonic components. An electronic musical instrument comprising constant generating means for generating a constant, and calculating means for calculating a constant corresponding to each harmonic component and the second function waveform to output an amplitude coefficient for each harmonic component.