JP3408653B2 - Envelope signal 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 signal generator for generating an envelope signal for adding strength and weakness to a musical tone signal in an electronic musical instrument such as an electronic piano or an electronic organ.

[0002]

2. Description of the Related Art Generally, an electronic musical instrument has a musical tone signal generator built therein. The musical tone signal generating device generates a musical tone signal having a tone color, pitch, etc. according to a player's panel operation or keyboard operation. A musical tone signal generating device generally generates a musical tone signal by adding an envelope signal to a musical tone waveform signal having a waveform corresponding to a tone color or a tone range and a frequency corresponding to a pitch.

The envelope signal is composed of a plurality of sections such as an attack section, a decay section, a release section, etc. (hereinafter sometimes referred to as "phase"). This envelope signal is generated by an envelope signal generator provided in the tone signal generator. A conventional envelope signal generator, when generating envelope signals for each phase, has a "target level parameter LV" that specifies a target level to reach and an "envelope speed parameter SP" that specifies the time to reach the target level. And are used. That is, the envelope signal having the required shape is created by controlling the current value of the envelope to be sequentially updated with the displacement according to the envelope speed parameter SP so as to reach the level specified by the target level parameter LV. ing.

However, when the envelope signal is generated by this method, the waveform generation time changes if the target level changes, and the comparison target for determining whether or not the target level is reached is changed each time the target level changes. There were drawbacks such as having to do so.

Therefore, the present inventor has invented an envelope signal generator for generating an envelope signal based on a normalized time variable signal in order to eliminate such a defect, and is currently applying for it (Japanese Patent Laid-Open No. Hei 4) -101197 gazette). According to the present invention, the current value of the envelope is
It approaches the target level of the current phase, and when it reaches a predetermined level, it transits to the next phase. The phase transition occurs when the time variable signal reaches the threshold level (fixed value) designated as the phase end value.

An envelope signal generator equivalent to the conventional envelope signal generator disclosed in Japanese Patent Laid-Open No. 4-101197 will be described below with reference to the drawings. It should be noted that the conventional envelope signal generator described here is configured to generate an envelope signal on the basis of a normalized time variable signal.
This is the same as the conventional envelope signal generator disclosed in Japanese Patent Publication No. 97, but is simplified for the sake of simplicity and understanding.

This conventional envelope signal generator is
As shown in FIG. 7, it is composed of an interface circuit 500, a time variable signal generation circuit 501, an amplitude level reproduction circuit 502, and a phase transition control circuit 503.

The interface circuit 500 includes an envelope signal generator and a central processing unit (not shown) (hereinafter "C").
PU ”. ) Controls the transfer of various data to and from. Specifically, the parameter τ sent from the CPU is sent to the time variable signal generation circuit 501 and the parameter L
To the amplitude level reproduction circuit 502, and the write signal Wf and the clear signal Clf to the phase transition control circuit 503. Also, the next phase parameter request signal RQf generated by the phase transition control circuit 503 is sent to the CPU.

Here, the above-mentioned parameters and signals are defined as follows. Parameter τ: Used to determine the time of a phase, that is, the time from the occurrence of a phase transition to the occurrence of the next phase transition. Parameter L: Used in this envelope signal generator to determine the target level. Write signal Wf: Used for requesting a phase transition when the shape of the envelope signal is forcibly changed. Clear signal CLf: Used to instruct to clear the request signal RQf. Next phase parameter request signal RQf: Used to request the parameter of the next phase from the CPU when switching the phase.

The time variable signal generation circuit 501 generates a time variable signal α normalized according to the parameter τ sent from the CPU via the interface circuit 500.
At this time, the variable signal α is supplied to the amplitude level reproduction circuit 502 and the phase transition control circuit 503, respectively. At this time, details of the variable signal generation circuit 501 will be described later.

The amplitude level reproducing circuit 502 reproduces the amplitude level of the envelope from the parameter L sent from the CPU via the interface circuit 500 and the time variable signal α sent from the time variable signal generating circuit 501. Then, the envelope signal Ec is output. Details of the amplitude level reproducing circuit 502 will be described later.

The phase transition control circuit 503 detects that the time variable signal α has reached the phase end value, and the transition signal trn indicating that and the next phase parameter request signal R.
Output Qf. Details of the phase transition control circuit 503 will also be described later.

FIG. 8 is a detailed circuit diagram of the time variable signal generation circuit 501. At this time, the time variable signal generating circuit 501 is also used as a time variable signal generating circuit in an embodiment of the present invention described later. In FIG. 8, the α memory 161 is composed of a random access memory (hereinafter, referred to as “RAM”) having the same number of storage positions as the number of tone generation channels or a shift register having the same number of stages as the number of tone generation channels. . In the following, the storage means configured in this way is referred to as a "time division compatible memory". The present value α _n of the normalized time variable signal is stored in the α memory 161 for each sounding channel. Here, “n” is the number of times of unit time for generating the envelope. The unit time is one cycle time required for the data read from the α memory 161 to be updated and rewritten. In the illustrated example, the current value α of the time variable signal
_n is calculated as α _n = α _n-1 −α _n-1 * τ (1).

The calculation process of the above equation (1) will be described with reference to FIG. First, when the transition signal trn becomes “1”, the fixed value “1” selected by the selector 160 is written in the α memory 161. As a result, the time variable signal α is initialized to “1”. The time variable signal α _n−1 read from the α memory 161 is used by the subtractor 162 and the multiplier 1
63. In the multiplier 163, the time variable signal α
_n-1 and the parameter τ are multiplied and supplied to the subtractor 162. The subtracter 162 is subtracted output α _n-1 * τ multiplier 163 from the variable signal alpha _n-1 time, the variable signal alpha _n at the next unit time is generated. At this time, the variable signal α _n is sent to the outside as the output of the envelope signal generator, and if the transition signal trn is “0”, the selector 1
It is written in the α memory 161 via 60. This completes the update of the time variable signal α in the unit time.
The time variable signal α generated in this way is, for example, as shown in FIG.
As shown in FIG. 1 (A), the waveform has an exponential asymptotic approach to zero in accordance with the value of the parameter τ. In FIG. 11A, P = 0 is the first phase (for example, attack phase), P = 1 is the second phase (for example, the first decay phase), and P = 2 is the third phase.
2 (for example, the second decay phase) are shown.

The τB memory 164 is a time division compatible memory, and is used as a buffer memory for temporarily storing the parameter τ sent from the CPU. That is, this τ
In the B memory 164, the parameter τ used in the next phase sent from the CPU 10 via the interface circuit 150 is stored for each sound generation channel. This τ
The parameter τ read from the B memory 164 is supplied to the τW memory 166 via the selector 165.

The τW memory 166 is a time division compatible memory, and the parameter τ used in the current phase is stored for each tone generation channel. The parameter τ stored in the τB memory 164 is transferred to the τW memory 166 via the selector 165 when the transition signal trn becomes “1”. The parameter τ read from the τW memory 166 is rewritten to the τW memory 166 via the selector 165 if the transition signal trn is “0”, and the original value is retained. . Also, τ
The parameter τ read from the W memory 166 is sent to the multiplier 163 and is multiplied by the time variable signal α as described above. The two-stage configuration of the τB memory 164 and the τW memory 166 allows the time variable signal α to be generated using the parameter τ of the current phase stored in the τW memory 166, and at the same time the parameter of the next phase. A parallel operation is possible in which τ is fetched from the CPU into the envelope signal generator.

As described above, the time variable signal generation circuit 50
The normalized time variable signal α generated at 1 is sent to the amplitude level reproduction circuit 502 and the phase transition control circuit 503 as described above.

FIG. 9 is a detailed circuit diagram of the amplitude level reproducing circuit 502. The amplitude level reproducing circuit 502 reproduces the AC amplitude level and the DC amplitude level lost by the normalization in the time variable signal generating circuit 501, and generates the current envelope value, that is, the envelope signal Ec. It should be noted that the envelope signal is a current value of the envelope that is continuous in time, and in the following, all are represented by the symbol “Ec”.

In FIG. 9, an Ei memory 511 is a time division compatible memory, and stores an initial value Ei of the envelope in the current phase for each sounding channel. The current value Ec of the envelope is calculated as Ec = (Ei−L) * α + L (2). The above (Ei-L) is the gain for the time variable signal α.

The calculation process of the above equation (2) will be described with reference to FIG. First, when the transition signal trn becomes “1”, the current value Ec of the envelope selected by the selector 510 is written in the Ei memory 511 as the initial value Ei of the new envelope in the next phase. on the other hand,
The initial value Ei of the envelope read from the Ei memory 511 is rewritten to the Ei memory 511 via the selector 510 if the transition signal trn is “0”, and the original value is retained. .

The output of the Ei memory 511 is the subtractor 51.
2 and the parameter L output from the LW memory 517 described later is subtracted. And this subtractor 51
The output of 2 (Ei-L) is the gain for the time variable signal α. The output of the subtracter 512 is multiplied by the time variable signal α in the multiplier 513. The output of the multiplier 513 is a signal whose AC amplitude level is reproduced. An example of this signal is shown in FIG. The output of the multiplier 513 is supplied to the adder 514 and is added to the parameter L output from the LW memory 517 described later. The DC amplitude level is reproduced by this addition and is output as the final envelope signal Ec as shown in FIG.

The LB memory 515 is a time division compatible memory, and is used as a buffer memory for temporarily storing the parameter L sent from the CPU. That is, this L
The B memory 515 includes the interface circuit 5 from the CPU.
The parameter L used in the next phase sent via 00 is stored for each sound generation channel. The parameter L read from the LB memory 515 is supplied to the LW memory 517 via the selector 516.

The LW memory 517 is a time division compatible memory, and stores the parameter L used in the current phase for each tone generation channel. The parameter L read from the LB memory 515 is passed through the selector 516 when the transition signal trn becomes “1” to the LW memory 517.
Transferred to. Then, the parameter L read from the LW memory 517 is rewritten to the LW memory 517 via the selector 516 if the transition signal trn is “0”, and the original value is retained. . In addition, the parameter L read from the LW memory 517
Is supplied to the subtracter 512 and the adder 514, and the above-mentioned calculation is performed. In this circuit, the parameter L
Is used only as a target level. The two-stage configuration of the LB memory 515 and the LW memory 517 allows the envelope signal Ec to be generated using the parameter L of the current phase stored in the LW memory 517, and at the same time the parameter L of the next phase. It is possible to carry out the parallel operation of taking in from the CPU to the envelope signal generator.

FIG. 10 is a detailed circuit diagram of the phase transition control circuit 503. This phase transition control circuit 503
Is mainly a transition signal trn for instructing phase transition when the time variable signal α reaches the phase end value (fixed value).
And the next phase parameter request signal RQ
generate f.

In FIG. 10, the comparator 520 compares the phase end value with the time variable signal α, and when the phase end value becomes larger than the time variable signal α, that is, A> B, becomes “1”. Is output. The output of this comparator 520 is O
It is supplied to R gates 521 and 522. This allows
A transition signal trn is output from the OR gate 521, and phase transition (switching) is performed. Also, the OR gate 5
“1” is written in the memory 526 through the 22 and the AND gate 525. At this time, the condition is that the write signal Wf for forcibly instructing the phase transition and the clear signal Clf for clearing the request signal RQf are not output from the CPU. As a result, the next phase parameter request signal RQf is output to the CPU,
The CPU responds to the next-phase parameter request signal RQf with the parameter τ and the parameter L of the next phase.
To the τB memory 164 and the LB memory 515, respectively.

The memory 526 is a time division compatible memory and stores data corresponding to the next phase parameter request signal RQf for each tone generation channel. This memory 5
If the write signal Wf or the request signal RQf is not supplied, the request signal RQf read from the memory 26 is rewritten to the memory 526 via the OR gate 522 and the AND gate 525, whereby the original value is obtained. Is retained. Even when the write signal Wf is sent from the CPU, the transition signal trn is set to “1”, and in this case, the phase transition is performed similarly to the case where the time variable signal α reaches the phase end value. Is done.
Since these functions and operations are not directly related to the present invention, description thereof will be omitted. For details, see JP-A-4-1011.
See the '97 publication.

[0027]

In the above-described conventional envelope signal generator, the phase end value is fixed to the same value in all phases. Therefore, FIG.
As shown in (A), in all the phases P0 to P2 , the phase transition occurs when the time variable signal α reaches the phase end value (threshold level).

However, since the phase end value can take only one value, it is determined to be optimal when the phase shifts from the attack phase ( P = 0 ) to the first decay phase ( P = 1 ), for example. . Therefore, the first
It is not always the optimum value when transitioning from the decay phase (P = 1) to the second decay phase ( P = 2 ). For example, there is a problem that an unnatural sound is generated when realizing the two-step decay necessary for the envelope of the diminished sound of a piano or the like.

FIG. 6A shows an example in which an envelope signal having two stages of decay (first decay and second decay) is created by using the above-mentioned conventional envelope signal generator (((in FIG. 11)). Corresponding to D)).

In the attack phase, the envelope signal asymptotic to the point Q ₁ on the parameter L ₁ is
At the point R ₁ where the phase end value is detected, the next decay phase is switched to. Then, the generation of the envelope signal in the first decay phase is subsequently started.
The envelope signal of the first decay phase is a signal that asymptotically approaches the point Q ₂ on the parameter L ₂ .
At the point R ₂ at which the phase end value is detected, the second decay phase is switched to. Then, the generation of the envelope signal of the second decay phase is subsequently started.

Here, paying attention to the shape of the envelope in the vicinity of the point R ₂ , the envelope of the first decay phase asymptotically approaches the point Q ₂ , so that the attenuation rate of the envelope signal becomes small in the vicinity of the point R ₂ . When actually listening to the musical sound produced by adding this envelope signal to the waveform of the piano and hearing it, it feels like the sound rises during the decay, and a sound that decays smoothly like an acoustic piano is obtained. I can't.

The present invention has been made in order to solve such a problem. Even if a musical tone has an envelope realized by two steps of decay, an envelope signal that realizes a sound with a smooth attenuation feeling is generated. It is an object of the present invention to provide an envelope signal generator capable of generating.

[0033]

In order to achieve the above object, the envelope signal generator of the present invention is a time variable for generating a normalized time variable signal for each section of an envelope composed of a plurality of sections. By calculating the difference between the target level of the envelope of the section and the final value of the envelope of the section immediately before the section with respect to the time variable signal from the signal generating section and the time variable signal generating section, The AC amplitude level reproducing means for reproducing the AC amplitude level lost by the normalization, and the signal reproduced by the AC amplitude level reproducing means, by further calculating the target level of the envelope of the section, An envelope signal generator having direct current amplitude level reproducing means for reproducing direct current amplitude level lost by normalization, wherein Means reproduces the AC amplitude level target level of the envelope as zero at a predetermined interval in said plurality of sections.

The calculation in the AC amplitude level reproducing means can be multiplication, and the calculation in the DC amplitude level reproducing means can be addition. Further, for the time variable signal generated from the time variable signal generating means, first the DC amplitude level reproducing means reproduces the DC amplitude level, and thereafter, for the signal for which the DC amplitude level is reproduced, the AC amplitude level reproducing means. It is also possible to reproduce the envelope signal by reproducing the AC amplitude level by performing the calculation in.

According to a first embodiment of the envelope signal generator of the present invention, the AC amplitude level reproducing means is
It further comprises selection means for selecting whether to use an externally provided target level parameter or zero as the target level of the envelope of the section. In this case, the selection in the selection means can be configured to be performed according to a selection parameter given from the outside.

In the second embodiment of the envelope signal generator of the present invention, the width of each section of the time variable signal generated by the time variable generating means is specified by a section parameter given from the outside. It further comprises a designation means. The width of this section can be configured to be controlled by, for example, applying a section parameter designating a threshold level from the outside and depending on whether or not the time variable signal has reached the threshold level.

Further, in a third embodiment of the envelope signal generator of the present invention, the section width designating means is constituted by a selecting means for selecting either a predetermined fixed value or a section parameter given from the outside. Has been done. In this case, the selecting means may be configured to select and output either a predetermined fixed value or a section parameter given from the outside according to the selection parameter. The target level parameter can be used as the section parameter selected by the selecting means.

[0038]

In the envelope signal generator of the present invention, the target level of the envelope of the section and the section immediately preceding the section with respect to the normalized time variable signal generated by the time variable signal generating means. The AC amplitude level lost by the normalization is reproduced by, for example, multiplying the difference from the final value of the envelope, and the target level of the envelope in the section is further added to the reproduced signal of this AC amplitude level. For example, by adding, the DC amplitude level lost by the normalization is reproduced to generate a final envelope signal. At this time, in the predetermined section, the AC amplitude level is reproduced by setting the target level of the envelope to zero.

As a result, during reproduction of the AC amplitude level, the difference between the target level of the envelope in the section and the final value of the envelope in the section immediately before the section is:
It becomes the final value of the envelope in the section immediately before that section, and further, for example, the DC amplitude level to be added becomes zero. Therefore, an envelope signal that asymptotically approaches zero from the final value of the envelope in the section immediately before the section is obtained. For example, the first shown in FIG.
During playback of the envelope signal in the decay section,
An envelope signal asymptotic from the point R ₁ which is the final value of the envelope in the attack section to the point Q ₂ which is zero is obtained. Therefore, if the reproduction of the envelope signal in the second decay section, which is the next section, is started from the point R ₂ which is the final value of the envelope in the first decay section, FIG.
As shown in (A), it is possible to avoid a situation in which the attenuation becomes gentle in the vicinity of the end point R ₂ of the first decay section, and it is possible to obtain a smooth attenuation feeling even for a musical tone having an envelope having two levels of decay. Can be realized.

It should be noted that which of the AC amplitude level and the DC amplitude level is first reproduced is arbitrary, and it can be determined as necessary depending on the convenience of realizing the envelope signal generator.

Further, in the first embodiment of the envelope signal generator of the present invention, whether the envelope signal which asymptotically approaches the target level of the envelope in the section or the envelope signal which asymptotically approaches zero is generated. Is selectable, it is possible to select whether to generate an envelope signal that asymptotically approaches the target level of the envelope in the section, or to generate an envelope signal that asymptotically approaches zero, as in the conventional envelope signal generator. This makes it possible to generate an envelope signal suitable for the required musical tone characteristics. Further, since which envelope signal is to be generated can be specified by a selection parameter given from the outside, if the envelope signal generator is connected to, for example, a computer, a different type depending on the selection parameter instructed by the computer. Can generate an envelope signal of

Further, in the second embodiment of the envelope signal generator of the present invention, the width of the time variable signal generated by the time variable signal generating means, that is, the width of each section of the envelope is given from the outside. It can be controlled by parameters. For example, when the time variable signal reaches the threshold level specified by the section parameter, it is possible to perform control so as to shift to the generation of the time variable signal in the next section. This means that an arbitrary section width can be realized depending on the section parameter.

Third Embodiment of Envelope Signal Generator of the Present Invention
In the embodiment of, the width of each section of the envelope is
Since it is determined based on either a fixed value set in advance or a section parameter given from the outside, the time variable signal has a predetermined threshold level (fixed value) like the conventional envelope signal generator. It is possible to select to move to the generation of the time variable signal of the next section at any time when the threshold level (variable) designated by the section parameter is reached or when the threshold value (variable) specified by the section parameter is reached.
This makes it possible to generate an envelope signal having a section width suitable for the required musical tone characteristics. Further, which of the above threshold levels is used to determine the section width can be specified by an externally provided selection parameter. Therefore, if the envelope signal generator is connected to, for example, a computer, the selection specified by the computer is performed. An envelope signal having a different interval width can be generated depending on the parameters.

In the first embodiment, when the envelope signal that gradually approaches zero is generated, the target level parameter that is necessary to generate the envelope signal that gradually approaches the target level of the envelope in the section is unnecessary. . Therefore, if the selection parameter in the third embodiment and the selection parameter in the first embodiment are shared, the target level parameter can be used as a section parameter given from the outside, and the number of parameters can be reduced. be able to.

[0045]

Embodiments of the present invention will now be described in detail with reference to the drawings. In order to facilitate understanding of the present invention,
Prior to the description of the embodiments, an example of an electronic musical instrument to which the envelope signal generator of the present invention is applied will be described with reference to FIG.

(1) Example of Electronic Musical Instrument to which Envelope Signal Generating Device is Applied As shown in FIG. 1, an electronic musical instrument to which the envelope signal generating device of the present invention is applied has a CPU 10 and a read-only memory (hereinafter referred to as “ROM”). 11), RAM 12,
A panel circuit 13, a keyboard circuit 14, an envelope signal generator 15, a waveform generator 16 and a digital filter circuit 17 are connected to each other via a system bus 30.

The CPU 10 controls the entire electronic musical instrument, and can be constituted by, for example, a microprocessor. The CPU 10 operates according to a control program stored in the ROM 11. For example, this CPU
10 sends parameters τ, L, Z to the envelope signal generator 15. In addition, sound generation processing according to key depression / key release, mute processing, tone color selection processing according to panel operation, effect selection processing, volume setting processing, etc. are performed.

The ROM 11 stores a control program for controlling the CPU 10, a tone color parameter, and various other fixed data. The timbre parameters are parameters for determining the waveform to be generated by the waveform generation circuit 16, parameters for determining the filter characteristics in the digital filter circuit 17, and the shape of the envelope signal generated by the envelope signal generator 15. Parameters (parameters τ, L, Z) and so on are included.

The RAM 12 is used as a work area in which the CPU 10 temporarily stores data. This RA
The M12 also stores, for example, panel data fetched from the panel circuit 13, key data fetched from the keyboard circuit 14, and the like.

The panel circuit 13 takes in signals indicating the setting states of a tone color selection switch, an effect selection switch, a volume setting switch, etc. mounted on an operation panel (not shown) and outputs them as panel data. The panel data output from the panel circuit 13 is sent to the RAM 12 via the system bus 30 and stored therein under the control of the CPU 10. The panel data stored in the RAM 12 is taken out by the CPU 10 at a predetermined timing and used for tone color selection processing, effect selection processing, volume setting processing, and the like.

The keyboard circuit 14 outputs key data generated in response to an operation of a keyboard (not shown). The keyboard circuit 14 includes a matrix circuit, a scanning circuit, an event detection circuit, a touch detection circuit, and the like. The matrix circuit is configured by arranging one or two key switches provided on each key of the keyboard and a diode as a pair at the intersection of the matrix. This matrix circuit is sequentially scanned by the scanning circuit in units of rows or columns. Then, the state (on or off) of each key arranged in each row or column is sequentially read. The signal indicating the state of each key read from the matrix circuit is sent to the event detection circuit,
Event data indicating the presence or absence of an event for each key is generated. Further, a signal indicating the state of each key is sent to the touch detection circuit, and touch data indicating the strength of key depression is generated. These event data and touch data are used as key data under the control of the CPU 10 under the control of the system bus 3
Sent to RAM 12 via 0 and stored. R
The key data stored in the AM 12 is taken out by the CPU 10 at a predetermined timing and used for sound generation processing, mute processing, and the like.

The waveform generating circuit 16 generates a digital musical tone waveform according to the parameters for determining the waveform included in the tone color parameters sent from the CPU 10. The generation of the digital musical tone waveform in the waveform generating circuit 16 can be realized by repeatedly reading the waveform data stored in a waveform memory (not shown). The digital musical tone waveform generated by the waveform generating circuit 16 is sent to the digital filter circuit 17. The waveform generating circuit 16 operates in a time division manner. That is, one cycle (processing unit) in this electronic musical instrument is divided into a number of time slots corresponding to the number of sounding channels,
In each time slot, sounding or muffling processing corresponding to one sounding channel is performed, and by repeating this in sequence, a plurality of sounds can be simultaneously sounded.

The digital filter circuit 17 includes the CPU 10
The digital tone waveform is filtered according to the parameter for determining the filter characteristic included in the tone color parameter sent from the digital tone waveform. The digital tone waveform output from the digital filter circuit 17 is the multiplier 1
8 are supplied. This digital filter circuit 17 operates in a time division manner.

The envelope signal generator 15 corresponds to the envelope signal generator of the present invention. The envelope signal generator 15 generates an envelope signal according to a parameter for determining the shape of the envelope included in the tone color parameter sent from the CPU 10. The envelope signal generated by this envelope signal generator is sent to the multiplier 18. The envelope signal generator 15 operates in a time division manner.

The multiplier 18 multiplies the digital tone waveform sent from the digital filter circuit 17 and the envelope signal sent from the envelope signal generator 15. By this multiplication, a digital musical tone waveform with an envelope added is generated. CP of this multiplier
U10 is supplied to the accumulation circuit 19. This multiplier 18
Works in a time-sharing manner.

The accumulator circuit 19 cumulatively adds the musical tone signals sent from the multiplier 18 in a time division manner. That is, the accumulator circuit 19 adds the digital musical tone waveforms of all sounding channels to generate one digital musical tone waveform. The output of the accumulator circuit 19 is supplied to the D / A converter 20.

The D / A converter 20 converts the input digital musical tone waveform into an analog musical tone waveform and supplies it to the sound system 21. Then, the musical sound is emitted in the sound system 21. Sound system 2
1 can be constituted by, for example, an amplifier for amplifying an analog musical tone waveform, a speaker, an earphone, or the like.

(2) Envelope signal generator FIG. 2 is a block diagram showing the configuration of the envelope signal generator 15. This envelope signal generator 15
Is the interface circuit 150, the time variable signal generation circuit 5
01, an amplitude level reproduction circuit 152, and a phase transition control circuit 153.

The interface circuit 150 corresponds to the interface circuit 500 already described with reference to FIG. The interface circuit 150 controls the transfer of various data between the envelope signal generator 15 and the CPU 10. That is, it differs from the interface circuit 500 shown in FIG. 7 in that a function of sending the parameter Z sent from the CPU 10 to the amplitude level reproducing circuit 152 is added. This parameter Z corresponds to the selection parameter of the present invention. This parameter Z is used to select whether to use the parameter L or the fixed value "0" as the target level. Also, the parameter Z
Is used to select whether to use the phase end value (fixed value) or the parameter L as data for determining the end of the generation of the time variable signal α. The other parameters τ and L correspond to the interval parameter and the target level parameter of the present invention, respectively, and their contents are the same as those described in the conventional example.

The time variable signal generation circuit 501 includes the CPU 10
To generate a time variable signal α normalized according to the parameter τ sent from the interface circuit 150. At this time, the variable signal α is supplied to the amplitude level reproduction circuit 152 and the phase transition control circuit 153. At this time, the variable signal generating circuit 501 is the same as that described in the section of the related art.

The amplitude level reproducing circuit 152 corresponds to the amplitude level reproducing circuit 502 already described with reference to FIG. The amplitude level reproducing circuit 152 reproduces the amplitude level of the envelope from the parameters L and Z sent from the CPU 10 via the interface circuit 150 and the time variable signal α sent from the time variable signal generating circuit 501. Then, the envelope signal Ec is output. At this time, the amplitude level reproducing circuit 502 is different from the above in that either the parameter L or “0” is selected as the target level by the parameter Z. Details of the amplitude level reproducing circuit 152 will be described later.

The phase transition control circuit 153 corresponds to the phase transition control circuit 503 already described with reference to FIG. The phase transition control circuit 153 detects that the time variable signal α has reached the phase end value, and the transition signal t
rn and the next phase parameter request signal RQf are output. At this time, it differs from the phase transition control circuit 503 described above in that either the parameter L or the phase end value (fixed value) is selected as the threshold level at which the phase transits depending on the parameter Z. Details of the phase transition control circuit 503 will also be described later.

(2-1) Amplitude Level Reproducing Circuit FIG. 3 is a detailed circuit diagram of the amplitude level reproducing circuit 152. This amplitude level reproducing circuit 152 is the same as the conventional amplitude level reproducing circuit 502 shown in FIG.
8, a ZB memory 179, a selector 180 and a ZW memory 181 are added. It should be noted that the selector 170, the Ei memory 171, the subtractor 1 of the amplitude level reproducing circuit 152
72, multiplier 173, adder 174, LB memory 17
5, the selector 176 and the LW memory 177 are the selector 510, the Ei memory 511, the subtractor 512, the multiplier 513, the adder 514, and the LB memory 5 shown in FIG. 9, respectively.
15, corresponding to the selector 516 and the LW memory 517,
Each function is also the same.

The ZB memory 179 is a time division compatible memory, and is used as a buffer memory for temporarily storing the parameter Z sent from the CPU 10. That is, in the ZB memory 179, the parameter Z used in the next phase sent from the CPU 10 through the interface circuit 150 is stored for each sounding channel. The parameter Z read from this ZB memory 179 is
It is supplied to the ZW memory 181 via the selector 180.

The ZW memory 181 is a time division compatible memory, and stores the parameter Z used in the current phase for each tone generation channel. The parameter Z read from the ZB memory 179 is sent to the ZW memory 181 via the selector 180 when the transition signal trn becomes “1”.
Transferred to. The parameter Z read from the ZW memory 181 is rewritten to the ZW memory 181 via the selector 180 if the transition signal trn is “0”, and the original value is retained. . In addition, the parameter Z read from the ZW memory 181
Is supplied to the selector 178 and the selector 190 (see FIG. 4) and used as a selection signal. The two-stage configuration of the ZB memory 179 and the ZW memory 181 described above allows the envelope signal E to be generated using the parameter Z of the current phase stored in the ZW memory 181.
At the same time as the generation of c, the parameter Z of the next phase can be fetched from the CPU 10 into the present envelope signal generator, which is a parallel operation.

The selector 178 corresponds to the selecting means of the present invention. The selector 178 is provided in the ZW memory 181.
Depending on the parameter Z from, the external target level parameter, that is, the parameter L or zero is selected as the target level of the envelope of the current phase.

That is, if the parameter Z read from the ZW memory 181 is “0”, the selector 178 selects the parameter L read from the LW memory 177 and supplies it to the subtracter 172 and the adder 174. To be done. The operation in this case is the same as the operation already described with reference to FIG.

On the other hand, if the parameter Z read from the ZW memory 181 is "1", "0" is selected by the selector 178, and the subtractor 172 and the adder 174 are selected.
Is supplied to. Therefore, L = 0 in the above equation (2), and the current value Ec of the envelope is calculated as Ec = Ei * α (3). The Ei is the gain for the time variable signal α. In other words, an envelope signal Ec that exponentially approaches zero is obtained with the envelope current value Ec at the end of the immediately preceding phase of the current phase as the initial envelope value Ei.

The calculation process of the above equation (3) will be described with reference to FIG. First, when the transition signal trn becomes “1”, the current value Ec of the envelope selected by the selector 170 is written in the Ei memory 171 as the initial value Ei of the new envelope in the next phase. on the other hand,
The initial value Ei of the envelope read from the Ei memory 171 is rewritten to the Ei memory 171 via the selector 170 when the transition signal trn is “0”, and the original value is held thereby. .

The output of the Ei memory 171 is the subtractor 17
The value "0" that is supplied to 2 and is output from the selector 178 is subtracted. That is, from the subtractor 172, the Ei memory 1
The output Ei of 71 is output as it is. This subtractor 17
The output Ei of 2 is the gain for the time variable signal α. The output of the subtractor 172 is multiplied by the time variable signal α in the multiplier 173. The output Ei * α of the multiplier 513 is a signal whose AC amplitude level is reproduced. An example of this signal is shown in the first decay phase (P = 1) of FIG.
The output of the multiplier 173 is supplied to the adder 174, and "0" output from the selector 178 is added. That is, the adder 174 outputs the output Ei * α of the multiplier as it is. The DC amplitude level is reproduced by this addition, and the final envelope signal Ec of the first decay phase as shown in FIG. 5D is output. By performing the same processing also in the second decay phase ( P = 2 ), it is possible to avoid a decrease in the attenuation rate at the end of the first decay phase, and to change from the first decay phase to the second decay phase. The smooth transition of is possible.

When the parameter Z is "1", L
The contents of the B memory 175 and the LW memory 177 do not contribute to the reproduction of the envelope signal Ec (reproduction of the AC amplitude level and the DC amplitude level).

In the above amplitude level reproducing circuit 152, a selector 178 is provided to set the target level of the envelope to a value given by the parameter L, or
Alternatively, it is possible to select "0", but the selector 17
The signal corresponding to the output of 8 may be fixed to zero. This can be achieved, for example, by removing subtractor 172 and adder 174.

(2-2) Phase Transition Control Circuit FIG. 4 is a detailed circuit diagram of the phase transition control circuit 153. This phase transition control circuit 153 is similar to the conventional phase transition control circuit 503 shown in FIG.
0 is added. The phase transition control circuit 1
The comparator 191, the OR gates 192 and 193, the inverters 194 and 195, the AND gate 196, and the memory 197 of 53 are the comparators 520 and 520 shown in FIG.
OR gates 521 and 522, inverters 523 and 5
24, corresponding to the AND gate 525 and the memory 526,
Each function is also the same.

The phase transition control circuit 153 mainly outputs the transition signal trn instructing the phase transition when the time variable signal α reaches the phase end value (fixed value) or the threshold level designated by the parameter L. At the same time, the next phase parameter request signal RQf is generated.

In FIG. 4, the selector 190 corresponds to the selecting means of the present invention, and the threshold level at the end of the phase is set to the phase end value (fixed value) according to the parameter Z read from the ZW memory 181. Or the parameter L read from the LW memory 177
Select whether or not. The output of the selector 190 is supplied to the A input terminal of the comparator 191.

When the parameter Z read from the ZW memory 181 is “0”, the phase end value (fixed value) is supplied to the comparator 191. The operation in this case is as shown in FIG.
The operation is the same as that already described with reference to.

On the other hand, when the parameter Z read from the ZW memory 181 is “1”, the parameter L read from the LW memory 177 is supplied to the comparator 191. In this case, the parameter L is not used to specify the target level, but is used to specify the phase transition timing of the time variable signal α. That is, when the parameter Z is "1", the "1" input terminal side is selected in the selector 178, so that the LW memory 177 is selected.
No parameter is required to specify the target level stored in. Therefore, in this case, the parameters stored in the LW memory 177 are not used to specify the target level, but are used to specify the width of each phase. Therefore, the LW memory 177 (LB memory 1
Since there is no state that 75) is not used, there is an advantage that the memory can be used efficiently.

That is, when the parameter Z read from the ZW memory 181 is "1", the comparator 191 compares the parameter L with the time variable signal α, and the parameter L becomes larger than the time variable signal α. In other words, if A> B, "1" is output. The output of this comparator 191 is OR
It is supplied to the gates 192 and 193. This makes O
A transition signal trn is output from the R gate 192, and phase transition (switching) is performed. Also, the OR gate 19
“1” is written in the memory 197 through the 3 and the AND gate 196. At this time, the clear signal Cl for clearing the write signal Wf and the request signal RQf for forcibly instructing the phase transition from the CPU 10
The condition is that f is not output. This allows
The next phase parameter request signal RQf is output to the CPU 10, and the CPU 10 receives the parameter τ, the parameter L, and the parameter Z of the next phase in the τB memory 16 according to the next phase parameter request signal RQf.
4, transferred to the LB memory 175 and the ZB memory 179.

FIG. 5A shows the first decay phase (P
= 1), the parameter Z is set to "1", and an example in which the parameter L is made larger than the phase end value (fixed value) to shorten the first decay phase is shown. If the parameter L is smaller than the phase end value (fixed value), the first decay phase can be lengthened. Thus, by setting the value of the parameter L to a desired value, the time of each phase can be adjusted.

In the case of this embodiment, the ZW memory 181 (Z
The parameter L stored in the storage position of the LW memory 177 (LB memory 175) corresponding to the position where "0" is stored in the B memory 179) is used as data for designating the target level and corresponds to "1". LW memory 177
The parameter L stored in the storage location of the (LB memory 175) will be used as data designating the width of each phase. Therefore, by appropriately determining the data to be stored in the ZW memory 181 (ZB memory 179) and the LW memory 177 (LB memory 175), the width of each phase can be set arbitrarily and the target level of the envelope can be zero or any value. Can be set to.

The phase transition control circuit 153 described above is used.
In the above, the selector 190 is provided, and it is possible to select whether the time of each phase is a value given by the parameter L or a fixed value. However, the selector 190 is removed and the output of the LW memory 177 is directly compared. It can also be configured to supply to the A input terminal of 191. In this case, the width of each phase is determined only by the value given by the parameter L. In this case, since the contents of the LW memory 177 (LB memory 175) are used to determine the width of each phase, the target level of the envelope cannot be set.

In order to avoid such an inconvenience, the LW memory 177 (LB memory 175) is left for setting the target level of the envelope, and a memory for storing parameters for determining the width of each phase is used. It may be newly provided.

[0083]

As described above in detail, according to the present invention, an envelope signal is generated that realizes a sound with a smooth attenuation even if it is a musical sound having an envelope realized by two-step decay. It is possible to provide an envelope signal generator capable of performing the above.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an electronic musical instrument to which an envelope signal generator of the present invention is applied.

FIG. 2 is a block diagram showing a configuration of an envelope signal generator of the present invention.

FIG. 3 is a circuit diagram of an amplitude level reproducing circuit of an embodiment of the envelope signal generator of the present invention.

FIG. 4 is a circuit diagram of a phase transition control circuit of an embodiment of the envelope signal generator of the present invention.

FIG. 5 is a waveform diagram for explaining the operation of the embodiment of the envelope signal generator of the present invention.

FIG. 6 is a diagram for comparing and explaining the operations of the envelope signal generator of the present invention and the conventional envelope signal generator.

FIG. 7 is a block diagram showing a configuration of a conventional envelope signal generator.

FIG. 8 is a circuit diagram of a time variable signal generation circuit of the envelope signal generator of the present invention and the conventional envelope signal generator.

FIG. 9 is a circuit diagram of an amplitude level reproducing circuit of a conventional envelope signal generator.

FIG. 10 is a circuit diagram of a phase transition control circuit of a conventional envelope signal generator.

FIG. 11 is a waveform diagram for explaining the operation of the conventional envelope signal generator.

[Explanation of symbols]

15 Envelope signal generation device 150 Interface circuit 501 Time variable signal generation circuit 152 Amplitude level reproduction circuit 153 Phase transition control circuit 161, 165, 170, 176, 178, 180, 1
90 selector 161 α memory 162, 172 subtractor 163, 173 multiplier 164 τB memory 166 τW memory 171 Ei memory 174 adder 175 LB memory 177 LW memory 179 ZB memory 181 ZW memory 191 comparator 192, 193 OR gate 194, 195 Inverter 196 AND gate 197 Memory

Claims (7)

(57) [Claims] 1. A time variable signal generating means for generating a time variable signal whose level gradually decreases according to an input parameter for each section of an envelope consisting of a plurality of sections, and a time variable signal from said time variable signal generating means. When the level becomes lower than a predetermined level, the end of the section is detected, and section transition control means for controlling the plurality of sections to transit in response to the detection, and a target level based on the time variable signal. Change towards
A amplitude level reproduction means for reproducing that envelope amplitude level, long interval is changed to the next by the period transition control means is in a predetermined interval, the amplitude level reproduction for reproducing an envelope amplitude level varies towards zero An envelope signal generating device comprising: 2. The amplitude level reproducing means further comprises a selecting means for selecting whether to use an externally provided target level parameter or zero as the target level. Envelope signal generator. 3. The envelope signal generator according to claim 2, wherein the selection in said selection means is performed according to a selection parameter given from the outside. 4. The width of each section of that variable signal generated by the time variable signal onset generating means, and further comprising a section width designating means for designating the segment parameter representative of said predetermined level The envelope signal generator according to any one of claims 1 to 3. 5. The section width designating means is a selecting means for selecting either a predetermined fixed value or a section parameter given from the outside.
The envelope signal generator according to claim 3. 6. The selection unit according to claim 5, wherein the selection unit selects and outputs either a predetermined fixed value or an interval parameter given from the outside according to the selection parameter. Envelope signal generator. 7. The envelope signal generator according to claim 6, wherein the target level parameter is used as the section parameter selected by the selecting means.