JP2699287B2 - Envelope generator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an envelope generating device.

[Prior art and its problems] As a typical conventional envelope generator, the entire envelope is composed of a plurality of segments (status) such as an attack and a decay, and a rate (slope) which is a parameter for defining an envelope waveform for each status. ) And a level (target value) are prepared, and a rate-level type envelope generating apparatus that calculates an envelope using the rate and the level during operation is known. In this type of envelope generator, the envelope waveform (function) to be generated can be defined by status, rate, and level, so that the storage capacity can be reduced, the user can easily program the envelope, and the envelope generator can be used. Has the advantage of simplifying the configuration.

On the other hand, as shown in FIG. 8, the generated envelope waveform becomes a polygonal line at the boundary of status switching as exemplified by the linear envelope (a) and the exponential envelope (b), leaving a serious problem of lack of naturalness. ing. That is, in the case of a natural instrument sound, the magnitude of the vibration does not change suddenly, and the volume of the sound is increased as illustrated in FIGS. 9 (a) and 9 (b), which illustrate the envelope shapes of the damped sound form and the sustained sound form, respectively. The envelope is expected to change smoothly, and not only the volume envelope, but also the timbre envelope and pitch envelope are generally considered to change smoothly with natural instrument sounds. It cannot generate a characteristic envelope.

[Object of the Invention] Accordingly, an object of the present invention is to provide an envelope generating device for an electronic musical instrument capable of generating an envelope having a smoothly changing characteristic.

According to the present invention, target value storage means for storing the target value of the envelope in each status, inclination data generation means for generating inclination data indicating the inclination of the envelope, and the last envelope value An envelope value calculating means for calculating a new envelope value based on the tilt data from the tilt data generating means; and a current status in which the envelope value calculated by the envelope value calculating means is stored in the target value storing means. In an envelope generating apparatus comprising: comparing means for comparing with a target value of the envelope in; and status updating means for updating a status based on a comparison result of the comparing means. Inclination setting value storage means for storing data; ,
When updating the status, the inclination data Rn of the envelope
(N is the number of envelope operations n = 1, 2,... Since the new status is set) is calculated from the previous inclination data R _n-1 and the inclination data Rc stored in the inclination setting value storage means.
Based on the following recurrence formula: Rn = (Rn _-1 + Rc) / 2.

Further, according to the present invention, the inclination data generating means includes an inclination set value storage means for storing the inclination data of the envelope in each status, and the inclination data Rn (n is a new status when the status is updated). ..) Is calculated based on the previous slope data R _n-1 and the slope data Rc stored in the slope set value storage means, using the following recurrence formula Rn = αR _n-1 + (1−α) Rc 0 ≦ α ≦ 1.

According to this configuration, at the transition of the status, the gradient of the envelope gradually changes from the gradient set for the previous status toward the gradient set for the subsequent status. Before and after the update, the slope of the envelope does not change discontinuously, and the envelope of the natural instrument sound can be more accurately approximated.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the embodiment shown in FIGS. 1 to 3, the envelope waveform is generated based on the slope data (set value of the slope of the envelope) set for each status and the target value of the envelope. According to the present invention, the inclination data as the difference value of the envelope is generated according to a recurrence formula including the set inclination data and the past inclination data instead of using the set inclination data as it is. In this embodiment, the recurrence equation is given by R _n = (R _n-1 + R _c ) / 2 (1) where n = 1, 2,. Here, the inclination data R _n is used in the n-th envelope calculation from becoming a new status, R _c is inclined data set for the current status.

From equation (1), R _n -R _c = (R _n-1 -R _c ) / 2 = (R _n -2 -R _c ) / 2 ² =... Therefore, R _n = R _c- ( R _c −R ₀ ) / 2 ⁿ (2) Here, _R0 is inclination data set for the previous status. Therefore, the columns R ₁ , R _2, ..., R _n of the tilt data after the status update are calculated from the values of the tilt data set for the previous status to the values R of the tilt data set for the current status. It will gradually change toward _c . For example, when _{R 0 = 2, R c =} -1, R 1 = 1/2, R 2 = -1 / 4, R 3 = -5 / 8, R 4 = -13 / 16, R 5
= −29 / 32 ... FIG. 4 shows the change of the envelope waveform in this case. In the figure, the dotted line shows the envelope waveform obtained when the set slope data R _c = -1 is used as it is as the envelope difference value according to the conventional technique, and the solid line is the envelope waveform generated by the embodiment. . As described above, according to the embodiment, since the inclination of the envelope changes smoothly by switching the status, it is possible to obtain an envelope close to the characteristics of the natural musical instrument sound as shown in FIG. As described later, the inclination data according to the equation (1) is generated by the envelope plate changing circuit 9 shown in FIG.

 The details will be described below.

FIG. 3 is a block diagram of an electronic musical instrument having the above-described envelope generation function. The key assigner 2 scans the key switch circuit 1 and determines the key code KC of the key being pressed.
Generates a key-on signal KN for starting sounding. Upon receiving the key-on signal KN, the envelope generation circuit 3 starts generating an envelope waveform E. Frequency information generating circuit 4 receives key code KC from key assigner 2 and generates frequency information FI corresponding thereto. The waveform generation circuit 5 receives the frequency information FI, accumulates it, generates waveform phase data, and generates waveform data based on the phase data. The generated waveform data is multiplied by the envelope signal E from the envelope generating circuit 3 and output as a musical sound waveform W. Next, when the key is released, a key-off signal KF
Is generated, and the envelope generating circuit 3 releases the envelope that has advanced to decay and sustain (only the sustained sound) after the start of the attack. When the release is completed, the envelope generating circuit 3 sends an envelope end signal EF to the key assigner 2. Upon receiving the envelope end signal EF, the key assigner 2 enters the sound ending state. The waveform generation circuit 5 resets the phase by the key-on signal KN so that the phase starts at the same phase when the attack starts. Although the function of the block has been mainly described above, a polyphonic configuration can be realized by performing time-division processing using a shift register or the like. The sound system 6 performs D / A conversion on the generated digital musical sound waveform signal, and emits the sound via an amplifier and a speaker.

FIG. 2 is a detailed block diagram of the envelope generating circuit 3. The envelope plate memory 7 stores inclination data indicating the inclination of the envelope set for each status, and the envelope level memory 8 stores the target value of the envelope set for each status. Both memories 7, 8 are addressed by status data ST indicating the current status from an envelope status circuit 12 which controls the status of the envelope. According to the present invention, the set tilt data ER of the current status from the envelope plate memory 7 is input to the envelope plate changing circuit 9, where the tilt data ER 'as an envelope difference value is generated. The changed inclination data ER 'is input to the envelope counter 10, and the envelope counter 10 outputs the changed inclination data ER'.
Is added to or subtracted from the current envelope value E ₀ to update the envelope value. The updated envelope value is compared with the envelope target value EL of the current status from the envelope level memory 8 by the comparison circuit 11. When the envelope value E ₀ reaches the envelope target value, the comparison circuit 11 sets “1”
Is generated to generate the comparison signal RH. That is,
The comparison signal RH is determined according to the sign bit ER ^MSB of the gradient data ER, as follows: (i) ER ^MSB = 0 (during rising) and E ₀ ≧ EL or (ii) ER ^MSB = 1 (during falling) and E ₀ ≦ It becomes “1” at EL.

The envelope value E ₀ from the envelope counter 10 is exponentially converted by the exponential conversion circuit 14 to become an exponential envelope E.

The envelope status circuit 12 receives the key-on signal KN from the key assigner 2 and attacks the status ST (00
Start the envelope as 0). Further, the envelope status circuit 12 outputs the envelope value from the comparison circuit 11.
Upon receiving the comparison signal RH of “1” indicating that E ₀ has reached the target value EL, the status is changed from attack (000) to decay (00).
1) Update the setting data extracted from the envelope plate memory 7 and the envelope level memory 8 by updating from decay (001) to sustain (010).
Further, the envelope status circuit 12 changes the status ST to release (011) in response to the key-off signal KF from the key assigner 2, and in the release (011), the comparison circuit 11
When receiving the signal RH for reaching the target value from, the status ST is set to the end state (110), and the envelope end signal EF is sent to the key assigner 2.

FIG. 1 is a detailed block diagram of the envelope plate changing circuit 9. The selection circuit 16 is a flip-flop (FF) 17
As the data to be taken into the
Or set tilt data from the envelope plate memory 7
One of the ERs is selected according to the selection signal from the OR gate 15. The OR gate 15 has a comparison signal RH from the comparison circuit 11, a key-on signal KN and a key-off signal KF from the key assigner 2.
Is entered. Therefore, the selection signal output from the OR gate 15 becomes "1" when the status of the envelope is updated, and at this time, the selection circuit 16 selects the gradient data ER set for the status before the update. .

For example, when the envelope starts, the key-on signal KN becomes “1”, and the selection signal of the OR gate 15 becomes “1”. At this time, the selection circuit 16 sets the slope for the status ST of the end state (000). Data, that is, initial inclination data ER _init is selected. Here, the status of the envelope status circuit 12 is updated from the end state (100) to the attack state (000), and the inclination data ER _attack set for this attack state is stored in the envelope plate memory 7.
Output from This attack setting inclination data ER _attack
Is input to the adder 18 of the envelope changing circuit 9, where it is added to the output ER _init from the FF 17, and the result is halved by the shift circuit 19. Therefore, the shift circuit 19
Output ER 'first change gradient data ER ₁ of a is the attack status, ER' = ER ₁ = a _{(ER init + ER attack) /} 2. Thereafter, the FF 17 captures the changed inclination data, and the adder 18 and the shift circuit 19 calculate the next changed inclination data.
Converting gradient data ER _n times th, ER '= ER _n = a _{(ER n-1 + ER attack} ) / 2. Therefore, the slope of the actual envelope in the attack state gradually changes from the value related to the initial value to the set slope value of the attack.

After that, the envelope value E ₀ becomes the attack target value EL
_When reaching the _attack , the reaching signal RH becomes “1”, the selection signal of the OR gate 15 becomes “1”, and the inclination data ER set for the attack state from the envelope plate memory 7.
_{The attack} is taken into FF17. Thereafter, the same operation as described above is repeated, and as a result, the decay status (00
In 1), the slope of the envelope changes smoothly from the slope of the attack part toward the set slope of the decay status. The same applies to the case where the key-off signal KF is generated. When the key-off signal KF is generated, the changed tilt data ER ′ is changed from the status set tilt before the key-off signal KF is generated to the key-off signal.
The transition to the set slope of the release status (011) after KF occurs smoothly.

At the time of switching of the status other than the attack, the output of the envelope plate changing circuit 9 has a value sufficiently close to the set slope before the switching, so that the output of the OR gate 15 is used instead of the output of the OR gate 15.
Only the key-on signal KN may be used as the selection signal of the selection circuit 16.

5 (a) and 5 (b) generated linear envelopes
Shows E ₀ and exponential envelope E. In this example, the initial settings
By increasing E _init , the slope of the envelope at the start of the attack is increased, and the envelope E by exponential conversion
Has improved the rising characteristics. It can be seen that at each transition from attack (A) to decay (D), decay (D) to sustain (S), and sustain (S) to release (R), the slope of the envelope changes smoothly. During the sustain, even if the arrival signal RH is given from the comparison circuit 11, the envelope status circuit 12
Keeps the status ST at sustain (010).

FIG. 6 shows a modification of the envelope plate changing circuit. The envelope rate change circuit 9M generates change gradient data R _n according to the following equation.

R _n = αR _n-1 + (1−α) R _c (3) 0 ≦ α ≦ 1, n = 1, 2, 3,... In this recurrence formula (3), the coefficient α = 1/2 For example, it becomes the same as Expression (1). Coefficient α represents the speed at which the change gradient data R _n converges to set the inclination of the current status, as α is larger i.e., closer to 1 the convergence rate becomes slow.

By transforming equation (3), the following is obtained: R _n = R _c −α ⁿ (R _c −R ₀ ). Therefore, when the status is updated, the slope of the envelope generated in the gradient data R _c set in the current status from the gradient data R ₀ set in the previous status, approaching at a speed corresponding to the convergence factor α Will go on.

FIG. 7 (a) shows an envelope obtained when R ₀ = 2, R _c = 1 and α = 1/2, and FIG. 7 (b) shows an envelope obtained when α = 3 /
The envelope obtained when it is set to 4 is shown. α
= For _{3/4, R 1 = 5} /4, R 2 = 11/16, R 3 = 17/64, R 4 = -
_{13/256, R 5 = -295} / 1024 slope varies so on ....

In the envelope rate change circuit 9M of FIG. 6, the coefficient α is given by the lower bits of the output ER envelope rate memory 7, the upper bits of the output ER represents the set gradient data ER _c.

Formation of the selection signal by the OR gate 15, the selection circuit 10, and
The configuration of FF17 is the same as that of FIG. FF in subtractor 28
Set gradient data ER _c of the current status is subtracted from the previous change gradient data ER _n-1 from 17. This output (ER _n-1
−ER _c ) × the multiplication of the coefficient α is executed in the multiplier 29 and the multiplier 2
It is added is set gradient data ER _c of the current status in the output of the _{9 α (ER n-1 -ER} c), new changes slope data ER _n (E
R ′) is generated. Therefore, the _{ER n = αER n-1 +} (1-α) ER c , and the calculation shown in Formula (3) is running.

An advantage of the modification shown in FIG. 6 is that an envelope having more various inclination change characteristics can be obtained by giving the convergence coefficient α an independent value for each step.

The description of the embodiment is finished above, but various modifications are possible within the scope of the present invention. For example, in the present invention, the function of the envelope plate changing circuit is to smooth or filter the slope data to change the slope data toward the set slope of the current status. Therefore, the recurrence formulas shown in equations (1) and (3), FIG.
Envelope rate change circuit for calculating the respective recurrence equation shown in the figure merely _{exemplary, R n = W c R c} + i ΣW i R n-ki (W c, W i is a weighting factor, R _n-ki it may be constituted by a circuit for calculating a change gradient data R _n according to recurrence formulas as shown by past changes gradient data). For _{example, R n = (R n-} 2 + R c) / 2, R n = (R n-1 + R n-2 + R c) / 3 Are examples of the recurrence formula.

Further, the envelope generator of the present invention can be applied not only to a volume envelope for controlling the volume of a musical tone, but also to a timbre envelope for timbre control and a pitch envelope for pitch control.

[Effect of the Invention] As described above in detail, according to the present invention, when the status is updated, the slope of the envelope is immediately switched to the set value of the slope set for the updated status. Instead, the slope is gradually changed to approach the slope of the set value, so that a smooth envelope waveform can be obtained, which is effective for natural synthesis of musical sounds.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of an envelope plate changing circuit used in an envelope generating circuit according to an embodiment of the present invention. FIG. 2 is a block diagram of the envelope generating circuit according to the embodiment. FIG. 3 is FIG. FIG. 4 is a block diagram of an electronic musical instrument including the envelope generating circuit of FIG. 4, FIG. 4 is a diagram illustrating a part of an envelope generated by the envelope generating circuit of the embodiment, and FIG. 5 is an envelope generated by the envelope generating circuit of the embodiment. FIG. 6 is a diagram showing a modification of the envelope plate changing circuit, and FIG. 7 is a diagram showing a part of an envelope generated by an envelope generating circuit using the envelope plate changing circuit of FIG. FIG. 8 is a diagram illustrating an envelope generated by a conventional envelope generating circuit, and FIG. 9 is a diagram illustrating an envelope of a natural musical instrument sound. It is. 3 ... Envelope generation circuit, 7 ... Envelope plate memory, 8 ... Envelope level memory, 9, 9M ...
... Envelope plate change circuit, 10 ... Envelope counter, 11 ... Comparison circuit, 12 ... Envelope status circuit.

Claims (2)

(57) [Claims] 1. A target value storage means for storing a target value of an envelope in each status, a tilt data generating means for generating tilt data indicating an inclination of the envelope, a previous envelope value and a tilt from the tilt data generating means. Envelope value calculating means for calculating a new envelope value based on the data, and comparing the envelope value calculated by the envelope value calculating means with the target value of the envelope in the current status stored in the target value storing means. In an envelope generating apparatus, comprising: comparing means; and status updating means for updating a status based on a comparison result of the comparing means, wherein the tilt data generating means stores tilt set value storing envelope tilt data in each status. Means and status updates In, the envelope slope data Rn of
(N is the number of envelope operations n = 1, 2,... Since the new status is set) is calculated from the previous inclination data R _n-1 and the inclination data Rc stored in the inclination setting value storage means.
And a slope data calculating means for calculating based on the following recurrence formula: Rn = (R _n-1 + Rc) / 2. 2. A target value storage means for storing a target value of an envelope in each status; a tilt data generating means for generating tilt data indicating the tilt of the envelope; a previous envelope value and a tilt from the tilt data generating means. Envelope value calculating means for calculating a new envelope value based on the data, and comparing the envelope value calculated by the envelope value calculating means with the target value of the envelope in the current status stored in the target value storing means. In an envelope generating apparatus, comprising: comparing means; and status updating means for updating a status based on a comparison result of the comparing means, wherein the tilt data generating means stores tilt set value storing envelope tilt data in each status. Means and status updates In, the envelope slope data Rn of
(N is the number of envelope operations n = 1, 2,... Since the new status is set) is calculated from the previous inclination data R _n-1 and the inclination data Rc stored in the inclination setting value storage means.
And an inclination data calculating means for calculating based on the following recurrence formula: Rn = αR _n−1 + (1−α) Rc 0 ≦ α ≦ 1.