JPH03230198A - Envelope generating device of electronic musical instrument - Google Patents

Abstract

PURPOSE:To eliminate a discontinuous variation of an inclination of an envelope and to more exactly approximate a natural musical instrument by changing an inclined set value of the envelope before and after in accordance with a prescribed recurrence formula in a turning point of a status. CONSTITUTION:An envelope waveform is generated, based on inclined data set to each status and a target value of an envelope. In this case, the inclined data being a differential value is generated by an envelope rate changing circuit 9 in accordance with a recurrence formula Rn = (Rn-1 + Rc)/2 which contains that which is set and the past one. In this regard, (n) = 1, 2,... and Rn and Rc denote inclined data used for an n-th envelope operation in a new status, and inclined data set to the present status, respectively. Accordingly, the inclina tion of an enveloped is varied smoothly by switching of the status and the envelope being approximate to a characteristic of a natural musical instrument sound can be obtained.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to an envelope generator for an electronic musical instrument.

[Prior Art and its Problems J] A typical conventional envelope generator generates an entire envelope into multiple segments such as attack and decay.
rate (#B) and level C-th W (m), which are parameters that define the envelope waveform for each status, are prepared, and the rate and level are used to calculate the envelope during operation. envelope generators are known. In this method of envelope generation, the envelope waveform to be generated (
1551 can be defined in terms of status, rate, and level, which has the advantage of requiring less storage capacity, facilitating the user's programming of envelopes, and simplifying the configuration of the envelope generator.

On the other hand, the generated envelope waveforms are shown in Figure 8 as straight envelope '(a) and Jfja envelope (b).
), it becomes a polygonal line at the point where the status changes, leaving a big problem that it lacks naturalness. In other words, in the case of natural musical instrument sounds, the magnitude of their vibrations does not change suddenly, and as shown in FIGS. 9(a) and 9(b), which illustrate the envelope shapes of a damped tone and a sustained tone, respectively, the volume changes. The envelope is expected to change smoothly, and not only the volume envelope but also the timbre envelope is generally thought to change smoothly in natural instrument sounds, but conventional envelope generators do not It is not possible to generate an envelope with the characteristics of natural instrument sounds.

[Object of the Invention] Therefore, an object of the present invention is to provide an envelope generator for an electronic musical instrument that can generate an envelope with smoothly changing characteristics.

[Structure and operation of the invention] According to the present invention, a target value storage means for storing a target value of an envelope in each status, a slope data generation means for generating slope data indicating the slope of the envelope,
envelope value calculation means for calculating a new envelope value based on the previous envelope value and the slope data from the slope data generation means; and storing the envelope value calculated by the envelope value calculation means in the target value storage means. In the envelope generating device for an electronic musical instrument, the envelope generating device for an electronic musical instrument comprises a comparing means for comparing a target value of an envelope in a current status of the electronic musical instrument, and a status updating means for updating the status based on a comparison result of the comparing means, the slope data generating means. is a slope setting value storage means for storing the setting value of the envelope slope in each status, and when updating the status, the slope of the envelope is changed from the slope set for the status before updating to the slope after updating. Inclination data for calculating the inclination data by changing the inclination indicated by setting A1 for the updated status in the inclination setting value storage means according to a predetermined recurrence formula so that the inclination gradually changes toward the set inclination. There is provided an engine power generation device for an electronic musical instrument, characterized in that it has a generating means.

According to this configuration, at the change of status, the slope of the envelope gradually changes from the slope set for the previous status to the slope set for the later status. The slope of the envelope no longer changes discontinuously before and after updating, and the envelope of the natural instrument sound can be approximated more accurately.

[Example 1 Hereinafter, the present invention will be described in detail with reference to the drawings.

In the embodiment shown in FIGS. 1 to 3, the envelope waveform is generated based on slope data (envelope slope setting value) set for each status and an envelope target value. According to the present invention, slope data as an envelope difference value is generated according to a recurrence formula that includes the set slope data and past slope data, rather than using the set slope data as is.

In this example, the recurrence formula is Rn - (Rn-+ + Rc) / 2
(+) n = 1.2, ...... given by, where Rn is the slope data used in the envelope calculation of [1] since the new status, and Rc is the current This is the slope data set for the status of .

From formula (1), Rn-Re'' (Rn-+-Rc)/2 = (Rn
2-Rc)/22 = --------, so Rn''Rc(RcRo)/2
' (2) where RO is the slope data set for the previous status. Therefore, columns R1 and R2 of the slope data after the status update.
...Rn is 0, which gradually changes from the slope data value set for the previous status to the slope data value Rc set for the current status, for example, When Ro=2, Rc=1, R
+ = 1/2. R7=1/4, R3=5/8. R
a--13/16, Rs=-29/32... In Figure 4, which shows the change in the envelope waveform in this case, the dotted line is set according to the prior art. 12 shows the envelope waveform obtained when using the slope data Rc=-1 as it is as the envelope difference value.
．． The solid line is the envelope waveform generated by the example.

In this way, according to the embodiment, the slope of the envelope changes smoothly when the status is switched, so that an envelope close to the characteristics of a natural musical instrument sound as shown in FIG. 5 can be obtained. As will be described later, the envelope plate changing circuit 9 shown in FIG. 1 generates slope data according to equation (1).

This will be explained in detail below.

FIG. 3 is a block diagram of an electronic music base having the above-mentioned envelope generation function. The key assigner 2 scans the key switch circuit 1 and determines the key code KC of the pressed key.
Then, a key-on signal KN for starting sound generation is generated. The envelope generation circuit 3 receives the key-on signal KN and starts generating the envelope waveform E.
receives the key code KC from the key assigner 2 and generates frequency information FI corresponding to it. The waveform generation circuit 5 receives the frequency information FI, accumulates it to generate waveform phase data, and generates waveform data based on it. The generated waveform data is multiplied by the envelope signal E from the envelope generation circuit 3 and output as the musical waveform W. When the key is released in the 0th order, the key assigner 2 generates a key-off signal KF, and the envelope generation circuit 3 , after starting the attack, the envelope, which had progressed to Decay and Sustain (sustained sounds only), is released. When the release is completed, the envelope generating circuit 3 sends an envelope end signal EF to the key assigner 2. key assigner 2
receives the envelope end signal EF and enters the 5-tone sound end state. In addition, in the waveform generation circuit 5, the phase is reset by the key-on signal KN so that it starts from the same phase at the start of the attack. If you use split processing, you can create a polyphonic configuration. The sound system 6 sends the generated digital music waveform signal to D.
/A conversion and output the sound through an amplifier and speaker.

FIG. 2 is a detailed block diagram of the envelope generating circuit 3. The envelope plate memory 7 stores slope data indicating the slope of the envelope set for each status, and the envelope level memory 8 stores the target value of the envelope set for each status. 7.8 is addressed by status data ST indicating the current status from the envelope status circuit 12 which controls the status of the envelope. According to the present invention, the setting slope data ER of the current status from the envelope plate memory 7 is input to the envelope plate changing circuit 9, where slope data ER' as an envelope difference value is generated. This modified slope data IER' is calculated by the envelope counter 10.
is input, and the envelope counter lO adds or subtracts this modified slope data ER' to the current envelope value EO to update the envelope value. Updated en o −7
' Value jt is compared with the envelope target value EL of the current status from the envelope level memory 8 in the comparator circuit 11. The comparison circuit 11 is configured to generate a comparison signal RH of "1" when the envelope value Eo reaches the envelope target value. That is, the comparison signal RH is determined according to the sign bit ERMS8 of the slope data ER.
(i) ER crocodile 5e=o (rising) and Eo≧EL or.

(ii) ERMS' = 1 (descending) and EO≦E
When it is L, it becomes "1".

The envelope value Eo from the envelope counter IO is subjected to index conversion in an index conversion circuit 14 to become an index envelope E.

The envelope status circuit 12 receives the key-on signal KN from the key assigner 2, sets the status ST to attack (OOO), and starts the envelope. Further, the envelope status circuit 12 receives "l" from the comparator circuit 11 indicating that the envelope value EO has reached the target value EL.
receives the comparison signal RH and attacks the status (000
) to Decay (001), Decay (001) to Sustain (010), etc., and update the setting data retrieved from envelope plate memory 7 and envelope level memory 8. 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 upon receiving the target value reaching signal RH from the comparison circuit 11 at release (o i B), the envelope status circuit 12 changes the status ST to release (011). is set to the end state (110), and an 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 0 selection circuit 16 is a flip-flop (FF).
As data to be imported into 17, the previous changed slope data E
Either R' or the setting slope data ER from the envelope plate memory 7 is selected according to the selection signal from the OR gate 15. The OR gate 15 receives the comparison signal RH from the comparison circuit 11 and the key-on signal K from the key assigner 2.
N and a key-off signal KF are input. Therefore, O
The selection signal output by the R gate 15 becomes "l" when the envelope status is updated, and at this time,
The selection circuit 16 selects the slope data ER set for the status before updating.

For example, when the envelope starts, the key-on signal KN becomes "1", and the selection signal of the OR gate 15 becomes "1".
'', and at this time, the selection circuit 16 enters the end state (00
Setting slope data for the status ST of 0), that is,
Select initial slope data E Rr nH. Here, the status of the envelope status circuit 12 is updated from the end state (100) to the attack state (000), and the slope data ERatt set for this attack state is updated.
acb is output from the envelope plate memory 7.

This attack setting slope data E Rat,ack is input to the adder 18 of the envelope changing circuit 9, where:
It is added to the output E Ri nH from the FF 17, and the result is halved by the shift circuit 19. therefore,
The first modified slope data ER+ of the attack status is the output ER' of the shift circuit 19.

ER' =ER+ = (ERinit+ERatta
ck) /2. After that, the FF 17 takes in the changed slope data, and the adder 18 and shift circuit 19 calculate the next changed slope data, so the nth changed slope data ERn after the start of the attack status is E R ' = E Rn = (E R1+-1+E
Rattack) /2. Therefore, the actual slope of the envelope in the attack state gradually changes from a value related to the initial value to the set slope value of the attack.

After that, the envelope value EO becomes the attack target value ELa
When reaching ttack, the arrival signal RH becomes l'',
The selection signal of the OR gate 15 becomes "1", and the slope data ERa+tdck set for the 7-tack state is taken into the FF 17 from the envelope plate memory 7. Thereafter, the same calculation as described above is repeated, and as a result, the slope of the envelope at Decay Status (001) changes smoothly from the slope of the attack portion to the set slope of Decay Status. The same is true when the key-off signal KF is generated, and in addition, the change slope data ER' changes from the setting slope of the status before the key-off signal KF is generated to the setting slope of the release status (011) after the key-off signal KFfi is generated. The transition is smooth.

Note that when switching the status other than attack, the output of the envelope plate changing circuit 9 has a value of A1 sufficiently close to the set slope before switching, so instead of the output of the OR gate 15, only the key-on signal KN is selected by the selection circuit 16. It may also be used as a selection signal.

Linear envelope E generated in Figures 5(a) and (b)
In this example, in which the initial setting Einit is set to a large value, the slope of the envelope at the start of the attack is increased, and the rise characteristics of the envelope E due to exponential conversion are improved. Attack (A) to Decay (D), Decay (D) to Sustain (S)
) It can be seen that the slope of the envelope changes smoothly at each transition from sustain (S) to release (R). Note that during sustain, even if the arrival signal RH is applied from the comparator circuit 11, the envelope status circuit 12 maintains the status ST at sustain (010).

FIG. 6 shows a modification of the envelope plate changing circuit 9M. This envelope plate changing circuit 9M generates changed slope data Rn according to the following equation.

Rn"αRn-+ + (1-α)Rc
(3) 0≦α≦1. n=1.2.3 ・-・-In this recurrence formula (3), if the coefficient α=l/2, &(1
) will be the same as The coefficient α represents the speed at which the modified slope data Rn converges to the set slope of the current status, and the larger α, that is, the closer it is to l, the slower the convergence speed.

By transforming equation (3), we obtain Rn = Re CtnCRc Ro ). Therefore, when the status is updated, the slope of the generated envelope approaches the slope data RO set in the previous status to the slope data Rc set in the current status at a speed corresponding to the convergence coefficient α. It turns out.

FIG. 7(a) shows RO: 2, Rc=lt', α; 1/2
The envelope obtained when
indicates the envelope obtained when α is set to 3/4. If α; 3/4, R1=5/4, R2=11
/16, R3= 17/64, Ra= 13/256
, R5=295/1024, and so on.

In the envelope plate changing circuit 9M of FIG. 6, the coefficient α is learned from the lower bits of the output ER of the envelope plate memory 7, and the upper bits of this output ER represent the set slope data ERC.

Formation of selection signal by OR game) 15 1 selection circuit 10;
The configuration of the FF 17 and the FF 17 is the same as that shown in FIG. Subtractor 28
In , the previous changed slope data ERn- from FF17
, the setting slope data ERC of the current status is subtracted from the current status. This output (E Rn- + E RC) is multiplied by the X coefficient α in the multiplier 29, and the output α of the multiplier 29 is
The setting slope data E Rc of the current status is added to (ERn-+ -ERc), and the new changed slope data E
Rn(ER') is generated. Therefore, ERn=
aERn-+ + (I Q)ERe, and the formula (3
) will have been executed.

The advantage of the modification shown in FIG. 6 is that by giving the convergence coefficient α an independent value for each step, envelopes with more diverse slope change characteristics can be obtained.

This concludes the description of the embodiment, 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 the slope data,
Alternatively, filtering may be used to change the slope data toward the set slope of the current status. Therefore, the envelope plate changing circuit for calculating the recurrence formulas shown in equations (1) and (3) and each recurrence formula shown in FIGS. 1 and 6 is merely an example, and Rn −We Re +ΣW1 Ro−k( Wc, W,
is the weighting coefficient, Rn- is the past changed slope data) Changed slope data Rn
For example, Rn =
(1'1n-2+Rc) / 2Rn' = (R
An example of a recurrence formula is n-1+ Rn-2+ Re )/3.

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

[Effects 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 slope setting value set for the updated status. Since the slope is gradually changed to approach the set value, a smooth envelope waveform can be obtained, which is effective for synthesizing natural musical tones.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a configuration example of an envelope plate changing circuit used in an envelope generation circuit according to an embodiment of the present invention, FIG. 2 is a block diagram of an envelope generation circuit according to an embodiment, and FIG. Electronic music including an envelope generation circuit =
FIG. 4 is a diagram illustrating a part of the envelope generated by the envelope generation circuit of the embodiment, and FIG. 5 is a diagram illustrating the entire envelope generated by the envelope generation circuit of the embodiment. , FIG. 6 is a diagram showing a modification of the envelope plate changing circuit. 7 is a diagram illustrating a part of an envelope generated by an envelope generation circuit using the envelope plate changing circuit of FIG. 6; FIG. 8 is a diagram illustrating an envelope generated by a conventional envelope generation circuit; FIG. 9 is a side view of the envelope of a natural instrument sound. 3... Envelope generation circuit, 7...
Envelope rate memory, 8...Envelope level memory, 9.9M...Envelope plate change circuit, 10...Envelope counter, ll...Comparison circuit 2・e畢φ−・Enoherob status circuit.

Claims (1)

[Scope of Claims] Target value storage means for storing a target value of an envelope in each status; slope data generation means for generating slope data indicating the slope of the envelope; envelope value calculation means for calculating a new envelope value based on the slope data; and comparing the envelope value calculated by the envelope value calculation means with the target value of the envelope in the current status stored in the target value storage means. an envelope generator for an electronic musical instrument, comprising: a comparison means for updating a status based on a comparison result of the comparison means; a slope setting value storage means for storing, and a slope of the envelope that gradually changes from the slope set for the status before updating to the slope set for the status after updating when the status is updated; An electronic musical instrument characterized by comprising: slope data generation means for calculating the slope data by changing the slope indicated by the setting value for the updated status in the slope setting value storage means according to a predetermined recurrence formula. envelope generator.