JPS6042957B2 - electronic musical instruments - Google Patents

Description

[Detailed Description of the Invention] This invention generates a fundamental wave (fundamental tone) and its harmonic components (overtones) corresponding to the pitch of an operating key, and generates amplitude coefficients corresponding to the fundamental wave and its harmonic components, respectively. The present invention relates to an improvement of an electronic musical instrument using a harmonic synthesis method that forms musical tones by multiplying and synthesizing the multiplied values, and particularly to an electronic musical instrument that can easily generate musical tones exhibiting moving formant characteristics.

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 waveform based on equation (1).

2 π Xo(qR)■DingCnSinwnqR...(1)Σ(
q■1, 2, ...) Here, Xo (qR) ... Waveform amplitude value at each sample point of the musical sound waveform.

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

n...Represents the order of each harmonic component 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 order of each harmonic component. Corresponds to the third harmonic (third overtone).

Cn...Amplitude coefficient (Fourier coefficient) for high frequency components of each order.

N: Number of sample points of one musical tone waveform at the highest frequency of the generated musical tone.

W: Total number of harmonics to be synthesized at each sample point.

There is a relationship of W=N/2.

Note that in the following explanation, harmonics include the fundamental wave, and the fundamental wave is the first harmonic.

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

In the figure, 1 is a key switch circuit provided in the keyboard section, which has key switches corresponding to each key of the keyboard section. When a certain key is pressed, the corresponding key switch is activated. It is configured to output a signal with a logical value of ゜"1" to the output line.This key switch circuit 1 has a built-in single tone priority circuit, and when two or more key switches operate at the same time, The "1" signal is output only to the output line corresponding to the key switch with a high priority.The output line corresponding to each key switch of key switch circuit 1 corresponds to the pitch of each key. The frequency number memory 2 is connected to the input side of the frequency number memory 2 in which the frequency number R stored in the key switch circuit 1 is stored.
A frequency number R corresponding to the pitch j of the key is read out from the j pitch.

On the other hand, the clock oscillator 3 outputs a clock pulse with a constant period, and this clock pulse is frequency-divided by W in the counter 4 to become the calculation interval timing signal Tx. In this case, RwJ is the total number of harmonics to be synthesized; for example, when synthesizing up to the third harmonic, RW=
It becomes 16j. The calculation interval timing signal generated in this manner is supplied to the gate 5. This gate 5 opens every time the calculation interval timing signal signature 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 adds the frequency number R each time the frequency number R is supplied via the gate 5 (that is, each time the calculation interval timing signal is generated).
is accumulated and an accumulated value QR that increases as 1R, 2R, 3R, etc. is output. Then, the interval adder 6 overflows when the accumulated value QR exceeds the modulus N of the adder 6, and thereafter repeats the same accumulation operation every time the calculation interval timing signal Tx is generated. Let's do it.

Thus, the accumulated value QR, which changes with each occurrence of the calculation interval timing signal Tx, is supplied to the harmonic interval adder 8 via the gate 7 which is gated by the clock pulse. In this case, since the clock pulse has a frequency W times that of the eyebrow calculation interval timing signal, the gate 7 is opened w times during one period of the calculation interval timing signal. As a result, the harmonic section adder 8 outputs the accumulated value QR from the gate 7 every time a clock pulse rises.
are added sequentially and the cumulative value RKlR is output. When the harmonic section adder 8 completes W accumulations, it is reset by the calculation section timing signal and performs the same operation thereafter. Therefore, this harmonic interval adder 8 calculates the cumulative value NqR (n=1, 2) which increases sequentially during one cycle of the calculation interval timing signal.
, 3...W). This cumulative value NqR is decoded in a memory address decoder 9, and the decoded output is supplied as an address signal to a sine function memory 10 which stores sequential sample point amplitude values of one period of a sine wave waveform at each address. , the memo l month 0 to sine amplitude event? Read Ir8qR. As is clear from the above explanation, the cumulative value Q of pitch interval addition) 6
R indicates the sequential sample point at which the musical waveform amplitude is to be calculated, and the cumulative value NqR of the harmonic interval adder 8) represents the phase of the n-th harmonic at the sequential sample point QRL currently being calculated. .

- As a result, from the sine function memo I river 0, the corresponding sump point Q
The sine amplitude value Si of each harmonic (including the fundamental wave) in R
7R (n=1, nwnq2...W) are sequentially generated in the order of fundamental wave (first harmonic), second harmonic, ...W harmonic.

In this case, the sample points of the musical sound waveform to be calculated shift sequentially every time the calculation interval timing signal tentatively occurs, but which 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 (Si7R) of each harmonic corresponding to the pitch of the operating key is sequentially time-shared.
It is generated n■Nq.

On the other hand, the memory address control device 11 is modulo W.
The counter 4 sequentially counts clock pulses Tc in synchronization with the counter 4 and outputs the count value to the harmonic coefficient memory 12 as an address signal n.

The harmonic coefficient memory 12 stores a harmonic amplitude coefficient C corresponding to the optimum amplitude value of each harmonic in order to obtain a desired musical timbre.
n is stored in each address, and when an address signal n (indicating the harmonic order) that changes sequentially in synchronization with the clock pulse Tc is supplied from the memory address control device 11, the address signal n is stored in each address. A harmonic amplitude coefficient Cn that sets the amplitude value of each harmonic is sequentially read out. This harmonic amplitude coefficient Cn is output to the harmonic amplitude multiplier 13. The harmonic amplitude multiplier 13 calculates the sine amplitude value Sjn? of each harmonic, which is sequentially read out from the sine function memory 10 in a time-sharing manner for each sample point. NqR is multiplied by the harmonic amplitude coefficient Cn set for each harmonic, and the multiplied value Fn=Cnsi
n? NqR 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 sequentially read out for each harmonic is multiplied by the corresponding harmonic sine amplitude value Si7qR, and then The amplitude value Fn for each harmonic is set by the voltage V1.

The accumulator 14 sequentially accumulates the amplitude value Fn of each harmonic output from the harmonic amplitude multiplier 13. When the calculation interval timing signal is generated, the gate 15 opens and the accumulated value of the accumulator 14 (representing the amplitude value at a certain sample point of the musical waveform) is output to the DA converter 16. At the same time, 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 sample point. Therefore, the D-A converter 16 receives amplitude values (digital signals) at sequential sample points of a musical waveform having a period corresponding to the pitch of the pressed key and having a waveform shape set by each harmonic amplitude coefficient Qn. is input every time the calculation interval timing signal is generated, and this digital amplitude value is converted into an analog signal and sent to the sound system 1.
7, a musical tone having a pitch corresponding to the pressed key and a tone corresponding to the harmonic amplitude coefficient Cn stored in the harmonic coefficient memory 12 is generated. On the other hand, an amplitude envelope is applied to a 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 KON output from the key switch circuit 1 when any key is pressed. The envelope waveform output from the instrument is multiplied by the musical tone signal, and amplitude envelopes such as attack, sustain, and decay are imparted to the generated musical tone. Incidentally, since an electronic musical instrument having such a structure is disclosed in Japanese Patent Laid-Open No. 48-90217, a detailed explanation of the structure and operation of each part thereof will be omitted.

JB Disadvantages of the Prior Art As is clear from the above explanation, the conventional electronic musical instrument using the harmonic synthesis method described above uses harmonics stored in the harmonic coefficient memory 12 at a frequency corresponding to the pitch of the pressed key. The tone is set by the amplitude coefficient Cn,
Moreover, it generates a musical tone with a volume corresponding to the amplitude envelope.

Therefore, the volume of the generated musical tone is only controlled in accordance with the amplitude envelope, and the tone color is the same at any pitch. However, in instruments that utilize the airways, such as wind instruments, for example, when the pitch (range) changes, the level of each harmonic component changes, thereby producing a musical tone with a tone unique to wind instruments. It exhibits so-called moving formant characteristics.

However, in the above-mentioned conventional harmonic synthesis electronic musical instrument, the harmonic coefficient memory 12 storing the harmonic amplitude coefficient Cn is addressed only by the signal n indicating the order of each harmonic, so each harmonic component Harmonic amplitude coefficient Cn multiplied by
does not change even if the pressed key tone changes, and the timbre of the generated musical tone does not change in any way, exhibiting so-called fixed formant characteristics.

For this reason, it has become difficult to generate musical tones with movable formant characteristics similar to those of musical instruments that utilize the airways, such as wind instruments. C. Object and Overview of the Invention The present invention was made in view of the above-mentioned drawbacks of conventional electronic musical instruments, and its object is to provide an electronic musical instrument that can easily generate musical tones exhibiting moving formant characteristics. Our goal is to provide the following.

For this reason, in the present invention, each amplitude coefficient that sets the amplitude value of each harmonic component constituting a musical tone is controlled not only by the order of each component but also by the -frequency (pitch) of the generated musical tone. ing. Hereinafter, the electronic musical instrument according to the present invention will be explained in detail using the drawings.

D Explanation of the structure and operation of the present invention (1) Explanation of the structure of the present invention FIG. 2 is a block diagram showing an embodiment of an electronic musical instrument according to the present invention, and the same parts as in FIG. 1 are designated by the same symbols. The explanation will be omitted.

In the figure, 18 is a counter that counts clock pulses Tc of a constant period output from the clock oscillator 3 and outputs the count output as an order number n indicating the order of each harmonic; 19 is a counter that is output from the counter 18. A multiplier 20 that multiplies the order number n by the frequency number R outputted from the frequency number memory 2 and supplies the multiplied value NR as an address signal to an amplitude coefficient memory 20, which will be described later, is shown in FIG. 3, for example. It is an amplitude coefficient memory which stores the amplitude level of each frequency corresponding to the desired formant characteristic, and is addressed by the multiplication value NR (representing the frequency of each harmonic) of the multiplier 19. The corresponding amplitude level is read out as an amplitude coefficient CnR and output to the harmonic amplitude multiplier 13. (2) Description of operation of this embodiment In the electronic musical instrument configured as described above, when a key in the keyboard section is pressed, the corresponding key switch closes.
A "1" signal is output to the corresponding output line of the key switch circuit 1.

The output signal of the key switch circuit 1 addresses the frequency number memory 2 to read out and output the frequency number R corresponding to the pitch of the pressed key. This frequency number R is
It is supplied to the pitch section adder 6 via the gate 5, which is opened in response to the calculation section timing signal signature created by dividing the constant period clock pulse output from the clock oscillator 3 by W in the counter 4. . The pitch interval adder 6 sequentially adds the frequency numbers R supplied each time a calculation interval timing signal characteristic occurs, and outputs an accumulated value QR. This accumulated value QR is determined by the gate 7 which is opened by the clock pulse Tc.
The harmonic section adder 8 outputs the cumulative value QR to the calculation section timing signal
1qR, 2qR, 3qR, etc. are sequentially added at the timing of the clock pulse Tc within one cycle of
A cumulative value NqR is generated that specifies the phase of the sine wave amplitude value at the sample point of each harmonic (including the fundamental wave).
After this accumulated value NqR is decoded in the memory add-on decoder 9, the sine function memory 10 is addressed and the sine amplitude value Sir8nqR of each harmonic is read out in a time-division manner. Such an operation is similarly performed for each sample point of the musical sound waveform corresponding to the pressed key pitch every time the calculation interval timing signal (2) is generated. On the other hand, counter 1
8 counts the clock pulses output from the clock oscillator 3, and supplies the count output to the multiplier 19 as the order number n.

The multiplier 19 multiplies the frequency number R corresponding to the pressed key pitch outputted from the frequency number memory 2 by the order number n outputted from the counter 18, and sends the multiplied value NR to the amplitude coefficient memory 20 as an address signal. to specify the corresponding amplitude coefficient CnR. As a result, the amplitude coefficient CnR specified by the multiplication value NR output from the multiplier 19 is read out from the amplitude coefficient memory 20.

In this case, RRJ, which is the multiplication value of the multiplier 19, represents the fundamental frequency of the musical tone to be generated, and Rno represents the harmonic order with respect to the fundamental wave (first harmonic) of the musical tone. . Therefore, the multiplier value represents the actual frequency of each harmonic. Therefore, the amplitude coefficient CnR for each frequency (NR) is stored from the amplitude coefficient memory 20.
is read out. In this case, the multiplication value is the sine amplitude value of each harmonic read from the sine function memory 10 (Si7R
), the harmonic amplitude multiplier 13 sets the amplitude of each harmonic using an amplitude coefficient BcnR corresponding to the frequency of each harmonic.

The amplitude value Fn for each harmonic, whose amplitude is set in the harmonic amplitude multiplier 13 in this way, is sequentially accumulated in the accumulator 14, and the accumulated value is gated every time the calculation interval timing signal desire occurs. The signal is supplied to the D-A converter 16 via the DA converter 15, and is produced as a musical tone by the sound system 17. In this case, the musical tones emitted from the sound system 17 have sine amplitude values Sjn of each harmonic depending on the pressed key pitch.
? Since the amplitude coefficient CnR given to NqR changes, the amplitude value Fn of each harmonic changes depending on the pitch of the pressed key, and thereby the tone changes depending on the pitch of the pressed key. Therefore, the amplitude coefficient Cr stored in the amplitude coefficient memory 20
By making IR correspond to desired formant characteristics, musical tones exhibiting movable formant characteristics can be easily generated. Note that in this embodiment, the order number n
The calculation between and the frequency number R is performed using a multiplier, but the order number n and the frequency number R are generated as a logarithmic order number 10gn and a logarithmic frequency number 10gR, respectively, and the NXR calculation is performed. RlOgn
The calculation value NR may be created by performing an addition process of +10gRJ and then converting the addition result into a natural number.

Further, in this embodiment, only the amplitude value of each harmonic is set by the multiplication value of the order number n and the frequency number R, but the pitch, envelope, etc. of each harmonic are determined by this multiplication value R. Various parameters may also be controlled.

E. Effects of the Invention As explained above, the electronic musical instrument according to the present invention creates each component of the fundamental wave and its harmonics corresponding to the pitch of the operated key, and applies each amplitude coefficient weighted to each of these components to the pitch of the operated key. Since settings are made based on both the height and the order of each component, the timbre of the generated musical sound exhibits movable formant characteristics, and the musical sound of musical instruments such as wind instruments can be easily generated using the airways. It is also possible to generate a human voice that exhibits movable formant characteristics, and has extremely excellent effects such as being able to be used not only as an electronic musical instrument for playing music, but also as a human voice generator.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a conventional harmonic synthesis electronic musical instrument, FIG. 2 is a block diagram showing an embodiment of an electronic musical instrument according to the present invention, and FIG. 3 is an example of a waveform stored in an amplitude coefficient memory. FIG. 1... Key switch circuit, 2... Frequency number memory (frequency number generation means), 3...
...Clock oscillator, 4...Counter, 6...
...Tone interval adder, 8...Harmonic section adder, 10...Sine function memory, 13...
・Harmonic amplitude multiplier, 14... Accumulator, 17.
... Sound system, 18 ... Counter (order number generation means), 19 ... Multiplier, 20 ...
...Amplitude coefficient memory (amplitude coefficient generation means).

Claims (1)

[Claims] 1. A musical tone is formed by creating components corresponding to the fundamental wave and its harmonics constituting a musical tone, multiplying each component by its corresponding amplitude coefficient, and synthesizing the multiplied values. In a harmonic synthesis electronic musical instrument, the frequency number generating means generates a frequency number corresponding to the pitch of a pressed key, the order number generating means generates an order number indicating the order of each component, and comprising a calculation means for calculating a frequency number generated from the generation means and an order number generated from the order number generation means, and an amplitude coefficient generation means for generating an amplitude coefficient corresponding to the calculation output of the calculation means, An electronic musical instrument characterized in that the amplitude value of each component is set by multiplying each component by an amplitude coefficient generated by the amplitude coefficient generating means. 2. The calculation means multiplies the frequency number and the order number, and the amplitude coefficient generation means is comprised of a memory that stores an amplitude level for each frequency as an amplitude coefficient corresponding to a desired formant characteristic, 2. The electronic musical instrument according to claim 1, wherein said memory is addressed by the calculation output of said calculation means. 3. The frequency number generation means generates a logarithmic frequency number obtained by logarithmizing the frequency number, and the order number generation means generates a logarithmic order number obtained by logarithmizing the order number, and the calculation The means adds the logarithmic frequency number and the logarithmic order number and converts the addition result into a natural number,
The amplitude coefficient generating means is comprised of a memory that stores the amplitude level for each frequency as an amplitude coefficient corresponding to a desired formant characteristic, and the memory is addressed by the calculation output of the calculation means. An electronic musical instrument according to claim 1.