JP2576390B2 - Envelope waveform generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an envelope waveform generator for tone control, and more particularly to an envelope waveform generator for setting an envelope slope for each section of an envelope such as attack, decay, sustain, and release. The present invention relates to an envelope waveform generating device that generates an envelope waveform having a desired waveform shape by calculating rate data.

[0002]

2. Description of the Related Art It has been conventionally performed to generate an envelope waveform for controlling a tone signal as data expressed in decibels (for example, Japanese Patent Publication No. 55-7600, Japanese Patent Publication No. 59-24433, Japanese Patent Publication No. 63-63). No. 42269). This is because, in decibel representation data, multiplication of linear representation data can be replaced with simple addition, which has the advantage of simplifying the operation circuit. In addition, envelope waveform data in decibel representation can be used. This is because, when converted to a linear representation, the attenuated portion is exponentially attenuated, which is preferable for audibility. However, in this case, for example, when the envelope waveform of the decibel expression having a shape as shown in FIG. 5A is converted into a linear expression, the waveform becomes as shown in FIG. 5B, and the attack portion lacks a steep rising edge. It will be. For this reason, a contrivance has been made conventionally to ensure that the attack portion has a steep rising edge as shown in FIG.

For example, in Japanese Patent Publication No. 59-24433, an accumulator temporarily generates an envelope waveform signal having a linear slope, and passes this envelope waveform signal through an attack curve conversion table in an attack section. It is converted to an attack curve with a bulge at the top.

[0004]

In order to convert a curve in an arbitrary section of an envelope waveform as in the prior art,
The method using the curve conversion table requires a conversion table, and also requires a multi-bit selector because it is necessary to select an envelope waveform portion by distinguishing between a section that is not subjected to curve conversion and a section that has undergone curve conversion. Become. Therefore, there is a disadvantage that the configuration becomes complicated. SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide an envelope waveform generating apparatus capable of giving a non-linear curve characteristic to an arbitrary section of an envelope waveform with a relatively simple configuration. It is.

[0005]

Means for Solving the Problems An envelope waveform generating apparatus according to the present invention supplies rate data corresponding to each of a plurality of sections of an envelope waveform, and is supplied from the rate data supplying means. And an envelope waveform forming means for forming an envelope waveform by calculating rate data.The envelope waveform data formed by the envelope waveform forming means is used in tone control as envelope waveform data expressed in decibels. In the envelope waveform generating device, in any one of the plurality of intervals, performing an operation of changing the rate data according to a current value of the envelope waveform,
Rate data changing means for performing the calculation so that the rate of change indicated by the rate data becomes relatively larger as the envelope waveform level indicated by the current value is smaller, and supplying the changed rate data to the envelope waveform forming means. Accordingly, even if the section in which the rate data change operation is performed is a section corresponding to either the rising edge or the falling edge of the envelope waveform, the envelope waveform that changes with a convex curve in the interval is determined by the envelope waveform forming means. It is characterized in that it is formed.

[0006]

The rate data changing means performs an operation of changing the rate data according to a current value of the envelope waveform in any of a plurality of sections of the envelope waveform. This calculation is performed such that the smaller the envelope waveform level indicated by the current value of the envelope waveform, the larger the change rate indicated by the rate data becomes. Accordingly, regardless of whether the section in which the rate data change operation is performed is the section corresponding to the rise or fall of the envelope waveform, the slope of the envelope waveform becomes steeper as the envelope waveform level in the section is relatively smaller. Conversely, as the envelope waveform level in the section is relatively large, the slope of the envelope waveform becomes gentler, and the envelope waveform that changes with a convex curve in the section is formed by the envelope waveform forming means. Therefore, an advantageous effect is obtained that a non-linear curve, that is, a convex curve characteristic can be added to an arbitrary section of the envelope waveform with a relatively simple configuration without using a curve conversion table or a selector. . Since the data of the envelope waveform formed by the envelope waveform forming means is used in the tone control as the envelope waveform data of the decibel expression, the section of the convex curve characteristic in the envelope waveform data of the decibel expression is obtained when the linear conversion is finally performed. In addition, tone control showing linearity or a characteristic closer to a straight line is performed by the envelope waveform. Thereby, for example, even in the same falling section, the above-described rate data change calculation is not performed in a normal decay or release section, and the above-described rate data is not changed in a forcing dump section requiring a rapid decay operation. By selectively using the change calculation, the curve characteristics for each section of the envelope waveform can be easily controlled.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of an envelope waveform generator 10 according to the present invention, and FIG. 2 shows an example of a configuration of an electronic musical instrument using the envelope waveform generator 10 for generating a volume and amplitude envelope waveform of a musical tone. Show.

First, referring to FIG.
Are provided with a plurality of keys for designating the pitch of a musical tone to be generated. A key pressed by the keyboard 11 is detected by a key press detection circuit 12. The key press detection circuit 12 outputs a key code KC of the detected pressed key and a key-on signal KON.
ON is given to the envelope waveform generator 10 respectively.
The tone signal generation circuit 13 generates a tone signal having a pitch corresponding to the given key code KC in the tone color selected by the tone color selection circuit 14. In this example, the tone signal generation circuit 13
Is a data logM in decibel expression (logarithmic expression).

[0009] The envelope parameter generating circuit 15
Various parameter data for setting the change rate and level of each section of the envelope waveform generated by the envelope waveform generating device 10, that is, each part of attack, decay, sustain, release, and forcing dump,
It is generated according to the tone color selected by the tone color selection circuit 14.
The parameter data for setting the change rate includes, for example,
There are attack rate data, decay rate data, sustain rate data, release rate data, and forcing damping rate data. These change rate data determine the slope of the envelope waveform for each section as shown in FIG. The parameter data for setting the level includes, for example, attack level data AL and decay level data DL. These level data AL and DL determine the attack level and the decay level in the envelope waveform as shown in FIG. The generated various parameter data is provided to the envelope waveform generator 10.

The envelope waveform generator 10 generates the envelope waveform data in a decibel expression (logarithmic expression) based on the given various parameter data and the key-on signal KON.
Generate logE. The adder 16 adds the envelope waveform data logE to the musical tone signal data logM expressed in decibels, thereby obtaining a logarithmic expression of a product (E · M) of E and M such that logE + logM = log (EM). As a result, a volume amplitude envelope is added to the tone signal. The output of the adder 16 is supplied to a logarithmic / linear conversion circuit 17 to obtain tone signal data EM having a volume amplitude envelope and a linear representation. The tone signal data is converted into an analog signal by a digital / analog conversion circuit 18 and reaches a sound system 19.

Next, the envelope waveform generator 10 will be described with reference to FIG. In the envelope waveform generating device 10, the arithmetic circuit 20 includes an attack rate data DBAR, a decay rate data DBDR, and a sustain rate data DB corresponding to respective parts such as attack, decay, sustain, release, and forcing dump.
By regularly and repeatedly adding or subtracting SR, release rate data DBRR, and forcing damping rate data DBFR in accordance with the clock pulse φ, FIG.
Envelope waveform data ENVDB as shown in FIG.
To form It is assumed that the envelope waveform data ENVDB is expressed in decibels, and is expressed by an attenuation amount having a maximum level of 0 dB. Therefore, when the bits of the data ENVDB are all “0”, the maximum level is 0 dB, and when the bits are all “1”, the level is 0 level.

In a specific section, that is, an attack section and a forcing dump section, the arithmetic circuit 20
The rate data is gradually changed by calculating the rate data according to the current value of the envelope waveform data ENVDB formed in step (1), whereby the calculation circuit 20 based on the rate data thus gradually changed. The envelope waveform formed by the calculation has such a characteristic that the rising slope is steep at the beginning and becomes gradually relatively gentle as shown in FIG.
In the section of the forcing dump section, the control is performed such that the slope of the attenuation is relatively gentle at first and gradually becomes steeper as shown in FIG.

A control signal for controlling the arithmetic circuit 20 is generated based on a key-on signal KON. The key-on signal KON is supplied to a rising and falling differentiating circuit 22 via an AND circuit 21. One signal is generated when the key-on signal KON rises (when the key is pressed) and when it falls (when the key is released). Key-on pulse KONP and key-off pulse KO
An FP is generated. The output of the flip-flop 23 applied to the other input of the AND circuit 21 is normally “1”, and becomes “0” when one of the conditions for performing a forcing dump is satisfied.

All bits of the envelope waveform data ENVDB output from the arithmetic circuit 20 are applied to an AND circuit 24. When all the bits are "1", the AND circuit 24
Is applied to the set input S of the flip-flop 23 as the ALL "1" signal. Also, this A
A signal obtained by inverting the LL “1” signal is supplied to the AND circuit 25. A key-off pulse KOFP is applied to another input of the AND circuit 25, and the output thereof is supplied to the flip-flop 23.
Is applied to the reset input R. If the envelope waveform level becomes zero before the key is released (before the key-off pulse KOFP is generated), the AND circuit 25 becomes inactive due to the signal “0” obtained by inverting the ALL “1” signal. Even when the key-off pulse KOFP occurs, the flip-flop 23 is not reset. In this case, the condition for performing a forcing dump is not satisfied.

On the other hand, if the key is released before the envelope waveform level becomes zero, the key-off pulse KOFP is generated when the ALL "1" signal has not yet been generated, so that the output of the AND circuit 25 becomes "1". And the flip-flop 23 is reset. As a result, the output of the flip-flop 23 becomes "0", making the AND circuit 21 inoperative, and enabling the AND circuit 26 with the inverted signal "1". The other input of the AND circuit 26 receives the key-on signal KON. When the next new key is pressed while the AND circuit 26 is enabled according to the output “0” of the flip-flop 23, the condition of the AND circuit 26 is satisfied by the rising of the new key-on signal KON, The output becomes "1". The output signal "1" of the AND circuit 26 is the forcing dump signal FD. On the other hand, if the envelope waveform level of the preceding sound becomes zero before the next new key is pressed, the flip-flop 23 is set by the ALL "1" signal, so that the forcing dump signal FD is not generated. Thus,
On condition that the key is released before the envelope waveform level becomes zero and the next new key is pressed, a forcing dump signal FD is generated, and in accordance with this forcing dump signal FD, as will be described later. A forcing dump operation is performed.

The key-on pulse KONP and the key-off pulse KOFP generated by the rise and fall differentiation circuit 22
Is supplied to a counter 27 for controlling the operation mode of the operation circuit 20. The counter 27 is a 2-bit binary counter, is reset to “00” by a key-on pulse KONP, and generates a clock pulse φ applied to the clock terminal CLK when the output signal of the AND circuit 28 applied to the enable terminal EN is “1”. The count is incremented by one at the timing, and "1" is
1 "is loaded. The 2-bit output of the counter 27 is used as the mode signals MD0 and MD1. The relationship between the contents of the mode signals MD0 and MD1 and the operation mode is as shown in Table 1 below.

[0017]

[Table 1]

The signal obtained by inverting the signal MD1 is the AND circuit 2
8, allowing the counter 27 to be counted up only during an attack or decay. The other input of the AND circuit 28 includes the envelope waveform data E
The output of the comparator 30 that compares the NVDB with the attack level data AL or the decay level data DL is given via an OR circuit 29 as described later.

The selector 310 outputs the mode signals MD0 and MD1.
Rate data DBAR, decay rate data DBDR, sustain rate data DB
One of SR and release rate data DBRR is selected, and the output is given to the “0” input of selector 320. Forcing damping rate data DBFR is applied to the "1" input of the selector 32, and according to the forcing dumping signal FD in the forcing dumping operation mode, the "1" input forcing damping rate data DBFR.
Select FR, otherwise select the output of selector 310 with "0" input.

Each rate data DBAR, DBDR, DB
SR, DBRR, and DBFR are data expressed in decibels. If you set the rate data by decibel expression,
The dynamic range of rate data that can be set with a limited number of bits can be expanded as exemplified in Table 2 below. Table 2 shows an example of the weight of each bit of the 6-bit binary data weighted by the decibel expression and the weight of each bit when this is converted into the linear expression. As a prior art for setting the setting information of a time function waveform such as an envelope waveform in a decibel expression, there is one disclosed in Japanese Patent Publication No. 59-24433, and therefore will not be described in detail here.

[0021]

[Table 2]

That is, linear 6-bit binary data can only express data in the range of 0 to 32,
6-bit binary data expressed in decibels can express data in the range of “1” to “2 to the 32nd power” when this is linearly converted. The rate data DBR expressed in decibels (any of DBAR to DBFR selected by the selectors 310 and 320) output from the selector 320 is supplied to a logarithmic / linear conversion circuit 52 via an adder 50 and an OR circuit group 51. The rate data is converted into linear expression rate data (which is indicated by RATE) and input to the inversion control circuit 33 of the arithmetic circuit 20.

Since the envelope waveform data ENVDB formed by the arithmetic circuit 20 is an attenuation amount as described above, a rising characteristic such as an attack part is obtained by repeatedly subtracting rate data, and an attenuation characteristic such as a decay part. Is obtained by repeatedly adding rate data.
In this case, an inversion control circuit 33 is provided to perform the subtraction by adding the complement.

In the operation circuit 20, the operation result is stored in the register 34, and the previous operation result (ENVDB) stored in the register 34 and the rate data (RATE) given via the inversion control circuit 33 are added. The addition is performed by the unit 35 (subtraction is performed in the case of complement addition). This adder 3
5 is stored in the register 34 via the OR circuit group 36 and the AND circuit group 37. A detailed example of the formation calculation of the envelope waveform data ENVDB in the calculation circuit 20 will be described later.

Adder 50, OR circuit group 51 and gate 5
The circuit section composed of the arithmetic circuit 2 in a specific section, that is, the section of the attack section and the section of the forcing dump,
0, the current value of the envelope waveform (ENVD
According to B), an operation for gradually changing the rate data DBR is performed. Accordingly, as described above with reference to FIG. 3A, the changed rate data (DB
R), the envelope waveform formed by the calculation by the calculation circuit 20 has a steep rising slope at the beginning of the attack section and gradually becomes relatively gentle, and a slope of the attenuation at the beginning of the forcing dump section. It is controlled so as to be relatively gentle and gradually steep.

The gate 53 receives the upper 4 bits of the envelope waveform data ENVDB formed by the arithmetic circuit 20. The NOR circuit 47 is connected to the control input of the gate 53.
0, the output of the logic comprising the OR circuit 480 is provided. The NOR circuit 470 receives the mode signals MD0 and MD1 and outputs "1" in the attack mode. This output signal and the forcing dump signal FD are connected to the OR circuit 4.
In addition to the control input of the gate 53 via the control signal 80, the signal passes through the upper 4 bits of the envelope waveform data ENVDB and is added to the adder 50 in the attack mode and the forcing dump mode, and the rate data DBR (that is, the attack rate data DBAR or Sing dam plate data DBFR) and envelope waveform data ENVD
The upper 4-bit data of the current value of B is added. Otherwise, the gate 53 is closed and the rate data DBR is not changed.

The adder 50 outputs the upper 4 bits of the decibel-expressed rate data DBR output from the selector 320 and the envelope waveform data ENVDB output from the gate 53.
Add the bit data. The output of the adder 50 passes through an OR circuit group 51 and is supplied to a logarithmic / linear conversion circuit 52. The OR circuit group 51 includes the carry output Co of the adder 50.
All bits "1" when carry out signal is output from
Is applied to the logarithmic / linear conversion circuit 52, otherwise, the output of the adder 50 is applied to the log / linear conversion circuit 52 as it is. When the addition result of the adder 50 overflows beyond the maximum value = all bits “1”, a carry-out signal is output, and the data supplied to the logarithmic / linear conversion circuit 52 is forcibly changed to the maximum value = all bits “1”. I do.

In modes other than the attack mode and the forcing dump mode, that is, in each of the decay, sustain, and release modes, the output of the OR circuit 480 is "0", the gate 53 is closed, and one input of the adder 50 is input. The data supplied from the gate 53 are all “0”, and the rate data DBR expressed in decibels output from the selector 320 is directly supplied to the logarithmic / linear conversion circuit 52.

On the other hand, in the attack mode or the forcing dump mode, the output of the OR circuit 480 is "1", the gate 53 is opened, and the envelope waveform data is supplied to one input of the adder 50 via the gate 53. E
Upper 4-bit data of NVDB is provided. And
The rate data DBR expressed in decibels (attack rate data DBAR or forcing damping rate data DBFR) output from the selector 320 and the upper 4-bit data of the envelope waveform data ENVDB are added by the adder 50. Envelope waveform data ENVDB
Is also data in the decibel expression, and the adder 50 substantially performs multiplication by adding data in the decibel expression.

For example, the rate data DBR is shown in Table 2 above.
And 6-bit data weighted as
Assuming that the upper 4 bits of the envelope waveform data ENVDB are weighted as shown in Table 3 below, the adder 5
At 0, 2-bit "00" is added to the lower part of the 4-bit ENVDB, and the weights of both bits are adjusted as described below to add 6-bit data.

[0031]

[Table 3]

In the operation of the adder 50, E
The upper 4 bits of the NVDB indicate the value of the rate data RATE in a linear expression corresponding to the rate data DBR according to the level of the envelope waveform data ENVDB.
Doubling to 2 n times as shown in FIG. That is,
The value n of the upper 4 bits of ENVDB expressed in decibels (where n is a decimal number and n = 1 corresponds to 6 dB)
Is added to the rate data DBR in the decibel expression, and the rate data RATE in the linear expression obtained by converting the addition result by the logarithmic / linear conversion circuit 52 is the value of the linear expression corresponding to the original rate data DBR. It is obtained by multiplying 2 to the nth power.

[0033]

[Table 4]

That is, the envelope waveform data ENVD
Each time the amount of attenuation of B increases by 6 dB (the level of 6 dB decreases), that is, when the amount of attenuation of the envelope waveform data ENVDB becomes n × 6 dB, the rate data R in linear expression is obtained.
The value is multiplied by 2 n times as compared with the case where the value of ATE is less than 0 to 6 dB. This means that the envelope waveform data E
The rate data R corresponds to the range of each 6 dB of the NVDB.
This means that the value of ATE can be switched to 2 n times so that the slope of the envelope waveform change becomes steeper as the envelope waveform level is lower.

As described above, the arithmetic circuit 20 controls the envelope waveform section of the attack section and the forcing dump section.
Each time the level changes by 6 dB corresponding to the current value level of the envelope waveform data ENVDB formed by the above, the value of the rate data RATE to be repeatedly added or subtracted by the arithmetic circuit 20 is raised to the nth power of 2 (envelope waveform). (The smaller the level, the larger the value of n).) The envelope waveform data ENVDB finally output from the arithmetic circuit 20 is as shown in FIG. In other words, the envelope waveform data of the attack part is generated with such characteristics that the rising slope is steep at the beginning and becomes gradually relatively gentle, and the envelope waveform data of the forcing dump part is relatively steep at the beginning of the attenuation and gradually becomes steep. It is generated with such characteristics.

Next, the calculation of the envelope waveform in the arithmetic circuit 20 will be described. First, "1" is given from the OR circuit 38 to all the OR circuits in the OR circuit group 36 by the key-on pulse KONP, and all "1" are set in the register 34. The output of the register 34 is output from the arithmetic circuit 20 as envelope waveform data ENVDB. At first, since the mode is the attack mode, the output of the NOR circuit 39 to which the mode signals MD0 and MD1 are input is "1", which is used as a signal to instruct the subtraction to the inversion control circuit 33, the adder 35, and the AND circuit 40. Given. The inversion control circuit 33 includes a logarithmic / linear conversion circuit 52
And exclusive OR circuits of a number corresponding to the number of bits of the rate data RATE given by the inverter circuit 39. When the signal given from the NOR circuit 39 is "1", each bit of the rate data RATE given from the logarithmic / linear conversion circuit 52 is inverted. When the signal is "0", the signal passes through the rate data as it is. Further, the output signal "1" of the NOR circuit 39 enters the carry input Ci of the least significant digit of the adder 35, and adds 1 to the inverted rate data to perform complement addition, that is, subtraction. Thus, in the attack mode, the rate data RATE is changed from the all “1” initially set in the arithmetic circuit 20.
(Attack rate data) is repeatedly subtracted.

As described above, during the attack section, the attack rate data D
BAR is selected, the gate 53 is opened, and the upper 4 bits of the current value of the envelope waveform data ENVDB are input to the adder 50. Therefore, the adder 50 adds (multiplies linearly) data corresponding to the current value of the envelope waveform data ENVDB to the attack rate data DBAR, and the attack rate data DB
Since AR is gradually changed in accordance with a change in the current value of the envelope waveform data ENVDB, the envelope waveform data ENVDB of the attack portion represented by the attenuation amount, which is formed by the arithmetic circuit 20, is represented in FIG. As shown in FIG. 3 (a), the rising edge is generated with such a characteristic that it becomes steep at first and becomes relatively gentle gradually.

In the attack mode, the attack level data AL is selected by the selector 41 and applied to the B input of the comparator 30. The A input of the comparator 30 is supplied with the envelope waveform data ENVDB from the arithmetic circuit 20, and when they match, a signal “1” is supplied from the output of B = A to the OR circuit 29. Further, B = A is not always satisfied depending on the value of the rate data, and may be exceeded. Therefore, the output of B <A of the comparator 30 is changed by the delay flip-flop 42 and the exclusive OR circuit 43. The output of the change detection circuit is input to the OR circuit 29. Envelope waveform data EN
When the value of VDB reaches the value of the attack level data AL, the output of the OR circuit 29 becomes “1”, and the AND circuit 2
"1" is given to the counter 27 via 8, and the counter 27 is counted up by one. This switches to the decay mode.

The envelope waveform data ENVDB
Becomes "0" before reaching the value of the attack level data AL, the AND circuit group 37 is closed to hold the value of the envelope waveform data ENVDB at all "0". Is provided. Before the subtraction result becomes all "0" at the time of subtraction, "1" is output from the carry output Co of the adder 35 every time, so that the AND circuit 40 to which the signal inverted from "1" is input does not operate. The gate of the AND circuit group 37 to which the signal obtained by inverting the output of the AND circuit 40 is input is open. However, when the subtraction result becomes all "0" or exceeds, "1" is not output from the carry output Co, the output of the AND circuit 40 becomes "1", and the gate of the AND circuit group 37 is closed. As a result, the envelope waveform data ENVDB maintains the maximum value of all “0”.

In the decay mode, the output of the NOR circuit 39 becomes "0" to instruct addition. Selector 31
Decay rate data DBDR is selected via 0, 320, and the corresponding rate data RATE is supplied to arithmetic circuit 20. This decay rate data DBD
The change of the rate data RATE corresponding to R is not controlled. In the arithmetic circuit 20, the envelope waveform data ENV
This decay rate data DBD for the current value of DB
The rate data RATE corresponding to R is repeatedly added. As a result, the envelope waveform data ENVDB is
As shown in (a) of FIG. In the decay mode, the decay level data DL is selected by the selector 41 and applied to the B input of the comparator 30. When the value of the envelope waveform data ENVDB reaches the value of the decay level data DL, the output of the OR circuit 29 becomes “1”,
"1" is given to the counter 27 via the AND circuit 28, and the counter 27 is counted up by one. As a result, the mode is switched to the sustain mode.

In the sustain mode, the selector 310,
Sustain rate data DBSR is selected via 320, and corresponding rate data RATE is supplied to arithmetic circuit 20. This sustain rate data DBS
The change of the rate data RATE corresponding to R is not controlled. In the arithmetic circuit 20, the envelope waveform data ENV
This sustain rate data DB for the current value of DB
The rate data RATE corresponding to the SR is repeatedly added. Thereby, the envelope waveform data ENVDB
Gently attenuates at a constant inclination as shown in FIG.

Eventually, a key-off pulse KOF due to key release
When P is generated, the counter 27 is loaded with "11", thereby switching to the release mode. In the release mode, the release rate data DBRR is selected via the selectors 310 and 320, and the corresponding rate data RATE is supplied to the arithmetic circuit 20. The rate data RATE corresponding to the sustain rate data DBSR is not changed and controlled. The arithmetic circuit 20 repeatedly adds the rate data RATE corresponding to the sustain rate data DBSR to the current value of the envelope waveform data ENVDB. As a result, the envelope waveform data ENVDB attenuates at a constant slope as shown in FIG.

During the release mode, the forcing dump condition is satisfied and the forcing dump signal F
When D is generated, the forcing damping plate data DBFR is selected by the selector 320 and provided to the adder 50. As described above, during the forcing dump period, the gate 53 is opened, and the upper 4 bits of the current value of the envelope waveform data ENVDB are input to the adder 50. Accordingly, the adder 50 adds (multiplies linearly) the data corresponding to the current value of the envelope waveform data ENVDB to the forcing damping rate data DBFR, and converts the forcing damping rate data DBFR to the envelope waveform data ENVDB.
, The envelope waveform data ENVDB of the forcing dump unit formed by the arithmetic circuit 20 is attenuated as shown in FIG. Is generated with such a characteristic that the slope of is relatively gentle at first and becomes gradually steep.

In the arithmetic circuit 20, when the carry-out signal is output from the adder 35 at the time of addition, that is, when the value exceeds all "1", the envelope waveform data ENV
An AND circuit 4 for keeping the value of DB all "1"
4 are provided. The AND circuit 44 includes an adder 3
5 and a signal obtained by inverting the output of the NOR circuit 39, and when a carry-out signal is output from the adder 35 at the time of addition, the AND circuit 44 outputs an OR circuit group 36 via the OR circuit 38. Is set to “1”, and the values of the envelope waveform data ENVDB are all set to “1”.

In this manner, in each section of the attack part and the forcing dump, the envelope waveform data ENVDB expressed in decibels having a desired non-linear curve characteristic as shown in FIG. This is output from the envelope waveform generating circuit 10 as envelope waveform data logE.

As described above, this envelope waveform generation
Envelope wave in decibels generated by the device 10
The shape data logE is shown in the block diagram of the entire electronic musical instrument in FIG.
Input to the adder 16 and the tone signal generation circuit 13
The tone signal data log also expressed in decibels generated from
Added to M, thus giving a volume amplitude envelope
The tone signal data log (E · M) output from the adder 16
Is done. The output data log (EM) of the adder 16 is
It is provided to the number / linear conversion circuit 17 and finally converted to a linear representation. The linear transformation, characteristic envelope waveform decibel representation, such as in FIG. 3 (a), will be converted to the characteristic as shown in FIG. 3 (b).
Therefore, in the linearly converted envelope, the attack portion rises steeply, and the forcing dump portion attenuates rapidly. In addition, in the example of FIG.
In the waveform generator 10, as described above, the data including the amount of attenuation is used.
Generates envelope waveform data logE in siber representation
Therefore, such an envelope waveform generator 10 is shown in FIG.
When applied to the actual circuit design,
The tone signal data expressed in decibels generated by the signal generation circuit 13
LogM also expresses its amplitude level value by attenuation.
Thus, the volume amplitude output from the adder 16
Music signal data log (EM) with envelope added
The amplitude level is represented by the amount of attenuation, and the logarithm
In the / linear conversion circuit 17, the tone signal comprising this attenuation amount
Logarithm after returning data log (EM) to normal level expression
/ Linear conversion is performed.

In the above embodiment, the rate data DBAR ~
Since the DBFR is set in the decibel expression, there is an advantage that the dynamic range of the rate data that can be set with a limited number of bits can be expanded as described above. Also, the slope of the envelope waveform portion in a specific section can be nonlinearly changed by changing the rate data by using a simple arithmetic circuit including the adder 50, the OR circuit group 51, and the gate 53 without using a special curve conversion table. There is also an advantage that the circuit configuration is simple because it is formed in a curve.

Further, the envelope waveform data ENVDB generated by the arithmetic circuit 20 is used as the envelope waveform data logE output from the envelope waveform generation circuit 10 as it is.
Therefore, there is also an advantage that the setting of the attack level data AL is easy. In other words, the envelope waveform data logE originally corresponds to the desired envelope waveform to be set, and the desired attack level is usually set on the scale of the envelope waveform data logE. In this regard, in the case of the above embodiment, since the envelope waveform data ENVDB to be compared with the attack level data AL in the comparator 30 is the envelope waveform data logE as it is, the envelope waveform data logE is immediately changed according to the attack level set on the scale of the envelope waveform data logE. Attack level data AL can be obtained.

The adder 16 and the logarithmic / linear conversion circuit 17 in FIG. 2 may be changed as shown in FIG. In this example, logarithmic / linear conversion circuits 54 and 55 separately convert tone signal data logM and envelope waveform data logE expressed in decibels into linear expressions, respectively.
Thereafter, a multiplier 56 multiplies the two to give an amplitude envelope to the tone signal. In this case, if the tone signal generating circuit 13 generates tone signal data M in a linear expression, the logarithmic / linear conversion circuit 55 is of course unnecessary. Note that, similarly to the above, as in the example of FIG.
Decibels whose envelope waveform generator 10 is composed of attenuation
When generating envelope waveform data logE of expression
In the logarithmic / linear conversion circuit 54,
The envelope waveform data logE consisting of
It is assumed that log / linear conversion is performed after returning to the current state.

[0050]

As described above, according to the present invention, in the case where an envelope waveform is formed by calculating rate data, the rate of change indicated by the rate data increases as the envelope waveform level indicated by the current value of the envelope waveform decreases. Is calculated so as to change the rate data according to the current value, so that the section in which the rate data change calculation is performed corresponds to either the rising edge or the falling edge of the envelope waveform. Even in a section, the slope of the envelope waveform becomes steeper as the envelope waveform level in the section is relatively smaller,
Conversely, as the envelope waveform level in the section is relatively large, the slope of the envelope waveform becomes gentler, and an envelope waveform that changes with a convex curve in the section can be formed. Therefore, a non-linear curve, that is, a convex curve characteristic can be added to an arbitrary section of the envelope waveform with a relatively simple configuration without using a curve conversion table or a selector.
It has an excellent effect. Also, for example, even in the same falling section, the above-described rate data change calculation is not performed in a normal decay or release section, and the above-described rate data change calculation is performed in a forcing dump section that requires a rapid decay operation. By performing the calculation properly, the curve characteristics of each section of the envelope waveform can be easily controlled.

[0051]

As described above, according to the present invention, when an envelope waveform is formed by calculating rate data, a calculation for changing the rate data according to the current value of the envelope waveform is performed, and the change is performed. Since the envelope waveform formation calculation is performed using the set rate data, an excellent effect is obtained in that the slope of the envelope waveform in an arbitrary section can be easily formed into a non-linear curve. That is, without using a curve conversion table and the like, with a relatively simple configuration,
A non-linear curve characteristic can be given to an arbitrary section of the envelope waveform.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an envelope waveform generator according to the present invention.

FIG. 2 is an exemplary block diagram showing one configuration example of an electronic musical instrument to which the envelope waveform generating device according to the embodiment is applied.

FIG. 3 is a view showing an example of forming an envelope waveform in the embodiment.

FIG. 4 is a block diagram showing a modification of FIG. 2;

FIG. 5 is a diagram showing a conventional example of forming an envelope waveform.

[Explanation of symbols]

 Reference Signs List 10 envelope waveform generator 20 arithmetic circuit 17, 52, 54, 55 logarithmic / linear conversion circuit

Claims (1)

(57) [Claims] 1. The method according to claim 1, wherein each of a plurality of sections of the envelope waveform is performed.
And rate data supply means for supplying rate data corresponding, provided with an envelope waveform forming means for forming an envelope waveform by calculating the rate data supplied from the rate data supply means, said envelope
Data of the envelope waveform formed by the
Tone control as envelope waveform data expressed in decibels
In the envelope waveform generator to be used in the in one of intervals of the plurality of sections, a row of Umono the operation to change the rate data depending on the current value of the envelope waveform, The engine indicated by this current value
The lower the envelope waveform level, the higher the rate data indicates
Perform the calculation so that the rate of change is relatively large,
The changed rate data with the rate data changing unit to be supplied to the envelope waveform forming means, depending on which
The section in which the rate data change operation is performed is
Equivalent to rising or falling of the waveform
Even in a section, an engine that changes with a convex curve in that section
A envelope waveform is formed by the envelope waveform forming means.
Envelope waveform generator being characterized in that so as to be.