JP2640560B2 - Envelope signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to, for example, an electronic musical instrument such as an electronic organ and the like, which generates an envelope signal for generating an envelope signal for adding strength to a tone signal. Related to the device.

(Prior Art) An electronic musical instrument such as an electronic organ has a tone signal generator, and a desired tone signal is obtained from the tone signal generator based on a player's key operation or the like.

In general, a tone signal generating device obtains a tone signal having high and low strength by adding an envelope signal to a tone signal having a waveform corresponding to a timbre or a tone range and a frequency corresponding to a pitch.

The envelope signal is, for example, as shown in FIG.
It has a phase P (= 0, 1, 2, 3) indicating a waveform switching phase such as an attack section, a decay section, and a release section. And each phase P usually has a different exponential function waveform.

Conventionally, in order to generate such an envelope signal, a “target level parameter LV” that specifies the target level L0, L1, L2 for each phase P, and a target level L
Two parameters, "envelope speed parameter SP", which specify the time to reach 0, L1, and L2, have been used.

That is, first, a difference between the target level specified by the target level parameter LV and the current value Δe of the envelope signal is obtained. Next, the difference value Δe is multiplied by the envelope speed parameter SP to obtain an increase in the envelope signal. Finally, a new current value Σe is obtained by adding the increment Δe × SP to the current value 、 e. Thereafter, the same process is repeated to sequentially update the current value Σe. As a result, the current value Δe of the envelope signal approaches the target level, and a waveform of a certain phase P is obtained.

By performing such processing for each phase P, an envelope signal as shown in FIG. 14 is obtained.

As described above, conventionally, the envelope signal is generated using the two parameters of the target level parameter LV and the envelope speed parameter SP.

However, in such a configuration, the waveform generation time of each phase P is not limited to the envelope speed parameter SP,
Since it also depends on the target level, if the target level changes even in the phase P of the same time width, there is a problem that the waveform generation time changes.

Also, in the conventional configuration, every time the target level changes,
There is a problem that a comparison target for determining whether or not the target level has been reached must be recalculated.

Further, in the conventional configuration, since the waveform is generated based on the target level, if the displacement to the target level is small,
An error occurs in the difference value Δe. Since this error is accumulated each time the current value Δe is updated, there is a problem that a desired waveform cannot be obtained.

(Problems to be Solved by the Invention) As described above, in the conventional envelope signal generation device, an envelope signal is generated using two parameters of the target level parameter LV and the envelope speed parameter SP. Therefore, (1) If the target level changes even in the same phase P, the waveform generation time changes.

(2) Every time the target level changes, the comparison target for determining whether or not the target level has been reached must be changed.

(3) If the displacement to the target level is small, a desired waveform cannot be obtained due to accumulation of errors.

There was a problem.

Therefore, the present invention does not change the waveform generation time even if the target level changes, and does not need to change the comparison target for determining whether or not the target level has been reached each time the target level changes. It is an object of the present invention to provide an envelope signal generator capable of obtaining a desired waveform even if the displacement up to the level is small.

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention relates to a method in which an envelope waveform generating process is performed to generate an envelope waveform composed of one or more phases. Parameter storage means comprising a first storage area for storing phase parameters, and a second storage area for storing parameters of a phase in which a subsequent envelope waveform generation process is performed; from a first storage area of the parameter storage means Supplied time parameter τ
A time variable signal generating means for generating a time variable signal that reaches a second reference value from a first reference value according to a time specified by _P (0 <τ _P <1); Phase switching detecting means for detecting phase switching by detecting that the second reference value has been reached; gain parameter _GP supplied from a first storage area of the parameter storage means; a waveform generating means in the first diagram for multiplying the output of the time variable signal generating means; output of the first amplitude parameter L _P and the first waveform generating means which is supplied from the storage area of the parameter memory means a second waveform generating means for adding the door; sequentially calculating a gain parameter G _P phases performed enveloped waveform generation processing subsequently be supplied to the second storage area of the parameter memory means Gain parameter calculation means; transfer means for transferring required parameters from the second storage area to the first storage area of the parameter storage means in accordance with the phase change detected by the phase change detection means And writing means for writing a parameter of a subsequent phase to a second storage area in response to the end of the transfer operation by the transfer means, characterized in that the envelope signal generator is characterized in that:

(Operation) According to the configuration described above, normalization processing (Normalization) is performed so that the maximum level of each phase is all the standard value 1.
(Hereinafter, simply referred to as “normalization”), it is only necessary to perform waveform generation processing on the time variable signal. Therefore, without using a parameter for specifying the target level, Waveforms can be generated using only time parameters that specify time. Thus, the waveform can be generated regardless of the target level, so that the waveform generation time does not change even if the target level changes. Further, each time the target level changes, it is not necessary to change the comparison target for determining whether the target level has been reached. Further, even if the displacement to the target level is small, a waveform of the hand can be obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing a configuration of one embodiment of the present invention.

Before explaining FIG. 1, an example of the configuration of an electronic musical instrument using the envelope signal generator of the present invention will be described with reference to FIG. 13 in order to make the following description easy to understand.

In FIG. 13, reference numeral 11 denotes a tone generator. The tone generator 11 generates a tone signal having a waveform corresponding to a timbre and a tone range and a frequency corresponding to a pitch in a time division manner for each sounding channel.

12 is an envelope generator. The envelope generator 12 generates an envelope signal for adding strength to a tone signal in a time-division manner for each tone generation channel.

The signal generation operation of these generators 11 and 12 is controlled by a central processing unit (hereinafter, referred to as “CPU”) 18 described later.

The tone signal output from the tone generator 11 is
The signal is supplied to the multiplier 13 and multiplied by the envelope signal output from the envelope generator 12. As a result, a tone signal to which strength is added in the amplitude direction is obtained.

The tone signal output from the multiplier 13 is supplied to the accumulator 14. The accumulator 14 accumulatively adds the tone signals output from the multiplier 13 in a time-division manner for each tone generation channel, and obtains a tone signal obtained by synthesizing tone signals of all tone generation channels.

The tone signal output from the accumulator 14 is converted into an analog signal by an analog / digital conversion circuit 15. The converted output is supplied to the sound system 17 after being amplified by the amplifier 16. This sound system 17
It is composed of speakers and headphones and converts a tone signal supplied as an electric signal into an acoustic signal. Thereby, the desired musical sound is emitted.

The signal generation operation of the generators 11, 12 is controlled as follows.

In the figure, reference numeral 19 denotes a panel switch unit. The panel switch section 19 is provided with various switches such as a tone color / envelope selection switch capable of selecting a tone color and an envelope signal for each tone generation channel. The switch operation state of the panel switch unit 19 is detected by a panel scan circuit (not shown). This detection output is supplied to the CPU 18 as a panel switch code.

Reference numeral 20 denotes a key switch unit. The key switch section 20 is provided with a keyboard switch for transmitting the key press and key release operations of the player to the CPU 18. The operation state of the key switch unit 20 is detected by the touch sensor 21 and supplied to the CPU 18. In this case, the detection output includes a key code indicating a key that has been pressed or released, and touch data that indicates the strength of the key pressed.

Reference numeral 22 denotes a read-only memory (hereinafter, referred to as “ROM”). The ROM 22 stores a program for controlling the operation of the CPU 18, a plurality of tone codes for designating a tone, a frequency number for defining a frequency of a tone signal, a parameter for generating an envelope signal, and various other fixed data. ing.

Note that the parameters for generating the envelope signal are not units of the envelope signal, but units of the phase P,
In other words, they are stored in units of one exponential function waveform.

In such a configuration, generation of a tone signal is performed as follows.

That is, the CPU 18 reads a tone color code for designating the tone color selected by the tone color / envelope selection switch of the panel switch unit 19 from the ROM 22 for each channel, and supplies the tone code to the tone generator 11. Also, CPU18
Supplies the key code supplied from the touch sensor 21 to the tone generator 11 as data indicating a sound range. Further, the CPU 18 reads out the frequency number corresponding to the pitch represented by the key code from the ROM 22 and supplies the frequency number to the tone generator 11.

The tone generator 11 is provided with a waveform memory for storing data having a waveform corresponding to a timbre or a tone range. In such a configuration, the tone generator 11
Generates an address for reading out target waveform data from the waveform memory based on the tone color code and the key code supplied from the CPU 18. Then, the waveform data selected by this address is read at the transmission rate specified by the frequency number. As a result, a tone signal having a waveform corresponding to a tone color or a tone range and having a frequency corresponding to a pitch is obtained.

 Next, generation of an envelope signal will be described.

Based on the envelope signal selected by the envelope selection switch of the panel switch unit 19, the CPU 18
The phase P (exponential function waveform) constituting the envelope signal is determined. Then, based on this determination result,
The parameters of each phase P are sequentially read out and supplied to the envelope generator 12. As a result, a desired envelope signal is generated.

Further, the CPU 18 can forcibly change the waveform of the envelope signal selected by the timbre / envelope selection switch of the panel switch unit 19 based on the waveform change information. That is, when there is the waveform change information, the CPU 18 reads the parameters of the phase P specified by the waveform change information from the ROM 22, and converts them into the parameters already supplied to the envelope generator 12. As a result, the waveform currently being generated is forcibly changed to the phase P waveform specified by the waveform change information.

The waveform change information includes, for example, after-touch information and key-off information represented by touch data output from the touch sensor 21.

The above is the configuration of an example of an electronic musical instrument using the envelope signal generator of the present invention.

Therefore, returning to FIG. 1, an embodiment of the envelope signal generator according to the present invention will be described in detail.

 First, an outline of an embodiment will be described with reference to FIG.

FIG. 2 is a signal waveform diagram for explaining the operation of FIG.

Now, it is assumed that an envelope signal having a waveform as shown in FIG. 2 (c) is generated. In order to generate this envelope signal, in this embodiment, first, as shown in FIG. 2A, a time variable signal normalized for each phase P is generated. That is, a waveform is generated by dividing the amplitude of the phase P waveform at the maximum amplitude of each phase P.

Next, a process for reproducing the AC amplitude level lost by the normalization is performed on the variable signal at this time. As a result, a signal as shown in FIG. 2 (b) is obtained.

Finally, the signal shown in FIG. 2 (b) is subjected to a process for reproducing the DC amplitude level lost by the normalization. As a result, an intended envelope signal as shown in FIG. 2 (c) is generated.

 The above is the outline of one embodiment.

In order to realize such processing, in the apparatus shown in FIG. 1, first, a differentiated circuit 31 generates a normalized time variable signal.

The differentiating circuit 31 includes a unit delay circuit 311 and a multiplier 312. In the unit delay circuit 311, 1 is set as an initial value at the switching position of each phase P.

In such a configuration, the initial value 1 set in the unit delay circuit 311 is supplied to a multiplier 312 and multiplied with the time parameter tau _P. The time parameter τ _P specifies the time to reach the target level, where 0 <τ _P <
It has a value of 1.

The multiplied output of the multiplier 312 is delayed by a unit time by the unit delay circuit 311. This delayed output is supplied to a multiplier 312 and is again multiplied by the time parameter τ _P.

Hereinafter, similarly, the multiplication is repeated every unit time, so that the waveform gradually approaches 0. As a result, a normalized waveform as shown in FIG. 2A is obtained.

The output α _P of the differentiating circuit 31 is supplied to a multiplier 32 and multiplied by a gain parameter _GP for reproducing an AC amplitude level.

As a result, as shown in FIG. 2B, a waveform in which the AC amplitude level is reproduced is obtained.

The output β _P of the multiplier 32 is supplied to the adder 33, where it is added to the amplitude parameter L _P for reproducing the DC amplitude level.

As a result, as shown in FIG. 2C, a waveform in which the DC amplitude level is reproduced is obtained.

When the waveform generation of a certain phase P is completed, the initial value 1 is set again in the unit delay circuit 311 and the multiplier 31
2. Parameters τ _{P + 1} and L _{P + 1 of the} next phase (P + 1) are supplied to the adder 33, respectively. This process corresponds to the CP in FIG.
Made from U18. On the other hand, the gain parameter _{GP + 1} of the multiplier 32 is automatically generated inside the envelope generator 12 in FIG.

Hereinafter, similarly, by repeating the waveform generation processing for each phase P, a signal having a continuous envelope is obtained as shown in FIG.

Note that the waveform generation processing for each channel is performed in a time division manner in each phase P.

Output alpha _P of the differentiating circuit _31, the output beta _P of the multiplier _32, the adder
33 the output E _P of each equation (1), (2), (3)
It is represented by

In the expressions (1), (2) and (3), n indicates the number of delays of the unit delay circuit 311.

_{α Pn = α P (n-} 1) × τ P ... (1) β Pn = α Pn × G P ... (2) E Pn = β Pn + L P ... (3) gain parameter G of the multiplier 32 is expressed by the following equation It is represented by (4).

T _{(P + 1) n} = E _Pn −L _{P + 1} (4) Here, T _{(P + 1) n} is a unit time of a phase (P + 1) next to the phase P currently being generated. Parameter. This parameter T _{(P + 1) n} is a certain phase P
Is generated during the generation of the waveform. And, in fact, the next phase (P + 1) generated by the switched position of the parameter T _{(P + 1) n} from one phase P is used as the gain G _{P + 1} of the next phase (P + 1) Is done.

Equation (4) is determined for the purpose of maintaining the continuity of the waveform at the switching position of the phase P.

As described above in detail, according to this embodiment, first, a normalized time variable signal is generated, and then the AC amplitude level and the DC Since the original envelope signal is generated by performing the process of reproducing the level, the waveform can be generated without using a parameter for designating the target level. Thus, a waveform can be generated regardless of the target level, and the waveform generation time does not change even if the target level changes. Further, each time the target level changes, it is not necessary to change the comparison target for determining whether the target level has been reached. Further, even if the displacement to the target level is small, a desired envelope waveform can be obtained.

FIG. 3 is a circuit diagram showing a configuration of another embodiment of the present invention.

In the above embodiment, the case where the normalized time variable signal is output as an exponential function waveform has been described.

On the other hand, in this embodiment, the normalized time variable signal is output as a linear waveform.

 This will be schematically described with reference to FIG.

In the figure, (f) shows the target envelope signal.

In order to obtain such an envelope signal, in this embodiment, first, as shown in FIG. 4 (a), a normalized time variable signal is output as a linear waveform.

Next, as shown in FIG. 4 (d), a process for reproducing the AC amplitude level is performed on the variable signal at this time.

Next, as shown in FIG. 4 (e), this AC amplitude level is reproduced as an exponential function waveform by log / linear conversion and output.

Finally, as shown in FIG. 4 (f), the signal having the exponential function waveform is subjected to a process of reproducing the DC amplitude level. As a result, a desired envelope signal is obtained.

In FIG. 4, (b) shows a request signal REQ for requesting the switching of the phase P. The request signal REQ is supplied from the envelope generator 12 to the CPU 18 at the switching position of each phase P. Upon receiving the request signal REQ, the CPU 18 performs a process of reading the next parameter to be supplied from the ROM 22 and supplying the parameter to the envelope generator 12.

(C) is a write flag Wflg indicating whether the waveform of the envelope signal selected by the envelope selection switch of the panel switch section 19 in FIG. 13 is forcibly changed. As described above, this light flag Wflg indicates that when there is waveform change information such as after touch or key off,
Set to 1 by CPU18. The figure shows a case where the write flag Wflg is 0 because there is no waveform change information.

Next, the configuration of FIG. 3 for realizing the above-described processing will be described.

First, a configuration for generating an envelope signal will be described.

In the figure, reference numeral 41 denotes a differentiating circuit which outputs a normalized time variable signal as a linear waveform.

This differentiating circuit 41 includes a selector 411, a time variable memory 412,
It is configured by a subtractor 413.

In the time variable memory 412, 1 is written as an initial value at the switching position of each phase P. This initial value 1 is CPU1
8 through the selector 411.

The initial value 1 written in the time variable memory 412 is
13, the time parameter τ _P supplied from the parameter memory 53 described later is reduced. This time parameter τ _P is a parameter that specifies the time to reach the target level, and has a value of 0 <τ _P <1.

The subtraction output of the subtractor 413 is supplied to the time variable memory 412 via the selector 411 and is written to the variable memory 412 at this time. The data written in the time variable memory 412 is read out after a unit time, and the subtractor 413 reduces the time parameter τ _P again. This subtraction output is output to selector 41
It is again supplied to the time variable memory 412 via 1 and is written to the variable memory 412 at this time.

Hereinafter, similarly, the subtraction process is repeated for each unit time. As a result, the amplitude level of the time variable signal decreases by τ _{P, and} a linear waveform as shown in FIG. 4A is obtained.

The output α _P of the differentiating circuit 41 is supplied to the multiplier 42 and multiplied by the gain parameter _GP read from the parameter memory 53. Thereby, as shown in FIG. 4D, a waveform in which the AC amplitude level is reproduced is obtained.

The output β _Pf of the multiplier 42 is converted from a linear waveform into an exponential function waveform by a logarithmic / linear conversion circuit 43. As a result, a waveform as shown in FIG. 4 (e) is obtained.

Output beta _PL logarithmic / linear conversion circuit 43 is supplied to the adder-subtractor 45 via the selector 44, and is added to the amplitude parameter L _P read out from the parameter memory 53. Thus, a reproduced waveform having a DC amplitude level is obtained as shown in FIG. 4 (f).

The output α _P of the differentiating circuit 41 is also supplied to a comparator 46 and compared with a threshold level TL (see FIG. 4A). When the output α _P becomes smaller than the threshold level TL, the comparator 46 supplies a request signal REQ as shown in FIG.

The request signal REQ is sent from the control signal generation circuit 47 to C
It is supplied to the CPU 18 via the PU interface 48. As a result, initialization for generating the waveform of the next phase (P + 1) is performed.

Hereinafter, similarly, each time the phase P changes, initialization is performed, and waveforms of all the phases P are obtained.

Next, a configuration for generating the gain parameter G of the multiplier 42 will be described.

Output E _P of the adder-subtracter 45 is held in the register 49 for each unit time. The selector 44 selects the output β _PL of the logarithmic / linear conversion circuit 43 in the first half of each unit time.
In contrast, in the second half, it selects the output E _P of the adder-subtractor 45 which is held in the register 49.

From the parameter memory 53, in the first half of each time unit, the amplitude parameter L _P of the current phase P is read in the second half, the amplitude parameter L _{P + 1} of the next phase (P + 1) is read.

In the first half of each unit time, the adder / subtractor 45
The output β of the logarithmic / linear conversion circuit 43 given via 44
The amplitude parameter _LP of the current phase _P is added to _PL .
In contrast, in the second half, amplitude parameters of the next phase read from the parameter memory 53 from the content E _P register 49 applied through selector 44 (P + 1)
Reduce L _{P + 1} . Thereby, the gain parameter T _{(P + 1) L} of the next phase P is obtained in the latter half of each unit time.

Gain parameter obtained per unit time from adder / subtractor 45
T _{(P + 1) L} are those generated based on the exponential waveform of been E _P. Therefore, this gain parameter T _{(P + 1) L}
Is linearly / logarithmically converted by the linear / logarithmic conversion circuit 50.

This linear / logarithmically converted gain parameter T _{(P + 1) L}
Are held in the register 51. The gain parameter T _{(P + 1) f} held in this register 51 is used by the selector 5 in the next unit time.
The data is written to the parameter memory 53 via the line 2.

Gain parameter T written in parameter memory 53
_{(P + 1) f} is updated for each unit time.

Then, the gain parameter T _{(P + 1) f} at the time when the output α _P of the differentiating circuit 41 reaches the threshold level TL is registered as the gain parameter G _{P + 1} of the next phase P.

As described above, the gain parameter G is automatically generated inside the envelope generator 12 in the waveform generation process of each phase P.

The control signal generating circuit 47 is controlled by the CPU 18 to
The operation of each unit such as the selector 411 is controlled.

FIG. 5 is a diagram showing a data storage structure of the parameter memory 53.

As shown, the parameter memory 53 stores a work area W for storing the parameters τ _P , G _P , and L _P of the current phase P.
And the parameters τ _{P + 1} , T of the next phase P
_It has a double structure having a buffer area B for storing _{(P + 1) f} ( _{GP + 1} ) and LP _{+ 1} . The areas W and B are further divided for each channel CH (= 0 to m).

In such a configuration, the parameters τ ₀ , G ₀ , L ₀ of the first phase 0 are stored in the work area W, and the parameters τ ₁ , L _{1 of the} next phase 1 are stored in the buffer area B. This process is performed by the CPU 18. In this case, the parameters are from CPU 18 to CPU interface 48, selector 52
Is supplied to the parameter memory 53 via On the other hand, the gain parameter T _1f (G ₁ ) of the next phase 1 is calculated in the process of the current phase 0 waveform generation processing and written into the buffer area B as described above. This writing is automatically performed inside the envelope generator 12.

After the first phase 0 waveform generation processing, the contents of the buffer area B are transferred to the work area W. This process is automatically performed inside the envelope generator 12. Thereafter, buffer area B contains 3
The parameters τ ₂ and L _{2 of the second} phase 2 are written.
The amplitude parameter T _2f of the third phase ₂ is generated in the process of the second phase P1, and the buffer area B
Is stored in

Similarly, every time the phase P changes, the parameters are transferred from the buffer area B to the work area W, and the time parameter τ and the amplitude parameter L are transferred to the buffer area B.
, The amplitude parameter G of the next phase (P + 1)
Is calculated and the result of this calculation is written in the buffer area B.

FIG. 6 is a flowchart showing a waveform generation process for each channel in a certain phase P.

This waveform generation processing for each channel is performed in a time-division manner in each phase P. Hereinafter, this will be described with reference to FIG.

FIG. 6 shows a process of forcibly changing the waveform (a process of forcibly switching the phase P9) in addition to the waveform generation process of each phase P and the switching process of the phase P.

First, the waveform generation processing of each phase P and the switching processing of each phase will be described.

In the figure, in step S1, the first channel 0 is designated by CPL18.

In the next step S2, the waveform generation processing of channel 0 and the generation processing of the amplitude parameter T _{(P + 1) f} of the next phase (P + 1) are performed. In step S2, FLX indicates logarithmic / linear conversion, and FXL indicates linear / logarithmic conversion.

In the next step S3, it is determined whether the write flag Wflg (CH) is 1 or not. When the write flag Wflg (CH) is 1, the waveform is forcibly changed. The details will be described later. On the other hand, if the write flag Wflg (CH) is 0, the process of step S4 is performed.

In this step S4, it is determined whether or not the output α _P (CH) of the differentiating circuit 41 has reached the threshold level TL. If the threshold level TL has not been reached,
Moving to step S7, channel 1 is designated.

In the next step S8, it is determined whether or not the channel CH has reached the maximum channel m. If not, the process returns to step S2.

Thus, the waveform generation processing of channel 1 and the generation processing of gain parameter T _{(P + 1) f} are performed.

Hereinafter, similarly, the waveform generation processing and the generation processing of the gain parameter T _{(P + 1) f} are performed up to the maximum channel m.

When the processing up to the maximum channel m is completed, the process returns from step S8 to step S1, and the processing from channel 0 to channel m is executed again. That is, the processing from channel 0 to channel m is repeated for each unit time.

In this process, when the output α _P (CH) of the differentiating circuit 41 reaches the threshold level TL, the process proceeds from step S4 to step S5. In this step S5, the request signal REQ (CH) is supplied to the control signal generation circuit 47.

In the next step S6, the contents of the buffer area B of the parameter memory 53 are automatically transferred to the work area W. Further, the CPU 18 allows the time variable memory 412 of the differentiating circuit 41 to be used.
The initial value 1 is written to the write flag Wflg.
(CH) is set to 0.

The time variable memory 412 has a data storage area for each channel CH as shown in FIG. Therefore, the initial value 1 is performed only for the data storage area of the corresponding channel CH. This is the write flag Wflg (C
The same applies to the setting of H).

Thereafter, the process proceeds to step S7, where the channel CH is updated. Therefore, this time, the phase switching process in steps S5 and S6 is performed for the next channel (CH).

When the phase switching process is completed for all the channel CHs, the process moves from step S8 to step S1, and the above-described process is executed again for the next phase P.

The processing of the CPU 18 at the time of phase switching is shown in FIG.

In step S11 of FIG. 8, channel 0 is set.

In the next step S12, the presence or absence of the request signal REQ (CH) is determined.

If there is no request signal REQ (CH), step S14
, Channel 1 is set.

In the next step S15, the channel CH is set to the maximum channel m
Is determined.

If the maximum channel m has not been reached, the process returns to step S12. Therefore, the above-described processing is performed on channel 1 this time.

Hereinafter, the same processing is repeated for each channel (CH). When the maximum channel m is reached, the process moves from step S15 to step S11, and the same processing is executed again from channel 0 to channel m for the next unit time.

On the other hand, when there is the request signal REQ, the process proceeds from step S12 to step S13. In step S13, processing such as writing the parameters τ _{P + 1} (CH) and L _{P + 1} (CH) to the buffer area B and writing the write flag Wflg (CH) to the internal register is executed.

The writing of the parameters τ _{P + 1} (CH) and L _{P + 1} (CH) is performed after the contents of the buffer area B have been transferred to the work area W.

Next, a process for forcibly changing the waveform (a process for forcibly changing the phase P will be described with reference to FIG. 9).

FIG. 9 shows a case where the waveform is forcibly attenuated in the middle of the attack portion so that no sound is produced.

When receiving the waveform change information for instructing such a waveform change process, the CPU 18 first reads from the ROM 22 a parameter for generating the waveform specified by the waveform change information, and stores the read parameter in the buffer area B of the parameter memory 53. Write. Thereafter, the CPU 18 sets the write flag Wflg to 1. As a result, in FIG.
When the processing in S3 is completed, the processing in step S6 is executed. As a result, the contents of the buffer area B are transferred to the work area W, and the initial value 1 is written to the time variable memory 412.
As a result, as shown in FIG. 9, a new waveform is forcibly generated from the middle of the attack portion.

The mode for forcibly changing the waveform is not limited to the mode shown in FIG. 9, but may be, for example, the following mode.

(1) When information indicating after touch is provided from the touch sensor 21 in FIG.

In this case, when the aftertouch information is given, the CPU 18 reads out the parameters of the phase P indicated by the aftertouch information from the ROM 22 and replaces them with the parameters stored in the buffer area B. Thereafter, since the contents of the buffer area B are transferred to the work area W, the waveform is changed according to the after touch. FIG. 10 shows an example of a waveform in this case.
FIG. 10 shows a case where there is aftertouch information in the middle of the release section.

(2) When information indicating a key-off is given from the touch sensor 21 in FIG.

For example, in an electronic organ, a tone is continuously output while a key is pressed, and the tone is attenuated when the key is released. Therefore, as shown in FIG. 11, if there is key-off information in the middle of the sustain section,
If the parameters of the release section are written in the buffer area B and are transferred to the work area W, it is possible to forcibly switch to the release section even in the middle of the sustain section.

(3) When adding a tremolo waveform to a tone signal.

In this case, as shown in FIG. 12, for example, by forcibly changing the waveform to a tremolo waveform in the middle of the decay section, a tone signal with a tremolo waveform added can be obtained. According to the configuration in which the tremolo waveform is added by forcibly changing the waveform of the envelope signal in this manner, compared to a configuration in which a tremolo adding circuit is provided after the accumulator 14 in FIG. It is easy to add a tremolo waveform in channel units or key units.

(4) When the performer can appropriately edit the waveform of the envelope signal as in a synthesizer.

In this case, the editing function can be easily realized by forcibly changing the waveform at the editing position to the specified waveform.

In this embodiment described in detail above, the same effects as those of the previous embodiment can be obtained, and further, the following effects can be obtained.

That is, in this embodiment, since the normalized time variable signal is output as a linear waveform by linear / logarithmic conversion, the differentiation processing of the differentiating circuit 41 can be performed not by multiplication processing but by subtraction processing. . Thus, the configuration of the differentiating circuit 41 can be simplified.

Since the time variable signal is output as a linear waveform, the waveform of each phase P always reaches the threshold level TL. Thus, it is possible to simplify the configuration of a comparator 46 for comparing the output alpha _P and the threshold level TL of the differentiating circuit 41.

Although several embodiments of the present invention have been described above, the present invention is not limited to such embodiments.

For example, in the embodiment of FIG. 3, a case has been described in which the subtractor 413 for differentiation and the adder / subtractor 45 for generating the envelope signal and for generating the gain parameter T _{(P + 1) L} are separately provided. However, in the present invention, one of them may be used in common and driven in a time-division manner.

In the above embodiment, the case where the present invention is applied to generation of an envelope signal for adding strength to a tone signal has been described. However, the present invention can be applied to generation of an arbitrary function waveform.

In addition to this, it goes without saying that the present invention can be variously modified and implemented without departing from the scope of the invention.

〔The invention's effect〕

As described in detail above, according to the present invention, the waveform generation processing may be performed on the normalized waveform, so that the waveform generation time does not change even if the target level changes. Further, every time the target level changes, it is not necessary to change the comparison target for determining whether the target level has been reached. Further, even if the displacement to the target level is small, an envelope signal having a target waveform can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing the configuration of one embodiment of the present invention, FIG. 2 is a signal waveform diagram for explaining the operation of FIG. 1, and FIG. 3 shows the configuration of another embodiment of the present invention. FIG. 4 is a signal waveform diagram for explaining the operation of FIG. 3, FIG. 5 is a diagram showing the configuration of the parameter memory 53 of FIG. 3, and FIG. 6 is a diagram for explaining the operation of FIG. 7 is a diagram for explaining the configuration of the time variable memory shown in FIG. 3, FIG. 8 is a flowchart for explaining the operation of FIG. 3, and FIG. 9 is a diagram for explaining the operation of FIG. 10 to 12 are signal waveform diagrams showing examples of waveform changing modes, and FIG. 13 is a diagram showing an example of a configuration of a tone signal generating device in which the envelope signal generating device of the present invention is used. FIG. 14 is a circuit diagram for explaining a conventional envelope signal generation process. 18 CPU CPU 31, 41 Differentiator circuit 32, 42, 312 Multiplier 33 Adder 43 Logarithmic / linear conversion circuit 44, 5
2,411: Selector, 45: Adder / subtractor, 46: Comparator, 4
7 ... Control signal generation circuit, 48 ... CPU interface, 4
9,51 ... register, 50 ... linear / logarithmic conversion circuit, 53 ...
... parameter memory, 311 ... unit delay circuit, 412 ... time variable memory, 413 ... subtractor.

Claims (2)

(57) [Claims] 1. A first storage area for storing parameters of a phase in which an envelope waveform generation process is being performed to generate an envelope waveform composed of one or more phases, and a subsequent envelope waveform generation. A parameter storage unit including a second storage area for storing a parameter of a phase in which a process is performed; and a first storage unit configured to store a parameter specified by a time parameter supplied from a first storage area of the parameter storage unit.
A time variable signal generating means for generating a time variable signal reaching a second reference value from the reference value of the above, and detecting a phase change by detecting that the time variable signal has reached a second reference value Phase switching detecting means for performing a phase change, a first waveform generating means for multiplying a gain parameter supplied from a first storage area of the parameter storing means and an output of the time variable signal generating means, A second waveform generating means for adding the amplitude parameter supplied from the first storage area of the parameter storing means and the output of the first waveform generating means, and a phase in which an envelope waveform generating process is subsequently performed. Gain parameter calculating means for sequentially calculating a gain parameter and supplying the gain parameter to a second storage area of the parameter storage means; Second said parameter memory means in accordance with the more the detected phase switched-
Transfer means for transferring required parameters from the storage area to the first storage area, and writing for writing parameters of a succeeding phase to the second storage area in response to the end of the transfer operation by the transfer means. Means, and an envelope signal generator. 2. The waveform of each phase of the envelope signal is an exponential function waveform, wherein the time variable signal generating means is configured to generate a time variable signal having a linear waveform. The envelope signal generating apparatus according to claim 1, wherein the waveform generating means is configured to output the time variable signal that has been converted into a linear waveform into an exponential function waveform by logarithmic / linear conversion.