JPH0254959B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an envelope adding device used in electronic musical instruments and the like.

Configuration of conventional example and its problems Conventionally, as a method for adding an envelope to a musical sound waveform, the envelope waveform is stored in an envelope memory, the envelope waveform samples are sequentially read from the envelope memory, and the combination of the envelope waveform sample and the musical sound waveform is Some methods perform multiplication and add an envelope, others display the stored contents of the envelope memory in logarithmic form to reduce the data volume, convert the data read from the memory exponentially, and then multiply it by the musical sound waveform. Some methods have been proposed, such as storing the trend between points in an envelope memory and sequentially accumulating the trend data to obtain the envelope waveform and multiplying it by the musical sound waveform to add the envelope. Memory is required. Furthermore, when adding a highly accurate envelope, there is a problem in that the capacity of the envelope memory becomes large.

OBJECTS OF THE INVENTION An object of the present invention is to provide an envelope adding device that does not have an envelope waveform memory and adds an envelope with a simple configuration using multiplication and shift processing.

Structure of the Invention The envelope adding device of the present invention includes a waveform generation section that generates a musical sound waveform, an envelope generation section that performs step processing at predetermined time intervals and generates an envelope signal, a multiplication section, and a shifter section. , divides the envelope signal into two groups, upper and lower, and multiplies the output signal of the waveform generator by the lower envelope signal in the multiplier, and shifts the multiplication result in the shifter based on the upper envelope signal. By performing the processing, a musical sound waveform with an envelope added is obtained.It does not have an envelope memory to store the envelope waveform, and adds the envelope using multiplication and shift processing.

Furthermore, the present invention includes a waveform generation section that generates a musical sound waveform, a step data generation section that performs step processing at predetermined time intervals and generates step data based on an envelope signal, a multiplier section, and a shifter section. Equipped with
The envelope signal is divided into two groups, upper and lower, and the multiplier section multiplies the output signal of the waveform generator by the lower envelope signal, and the shifter section shifts the multiplication result based on the upper envelope signal. By doing this, a musical sound waveform with an envelope added is obtained.

Furthermore, the present invention includes a waveform generation section that generates a musical sound waveform, a level setting section that sets the amplitude level of the generated musical sound waveform, and a step-up process that is performed at predetermined time intervals based on the amplitude level set by the level setting section. The envelope signal is divided into two groups, upper and lower, and the multiplication section generates the output signal of the waveform generation section and the lower envelope signal. Then, the multiplication result is subjected to shift processing in the shifter section based on the upper envelope signal, thereby obtaining a musical sound waveform with an envelope added, and a musical sound waveform at the amplitude level set in the level setting section. It's something you get.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings.

First, the envelope addition method will be explained.

The envelope signal ED consists of 20 bits, the upper 4 bits are EDU (Q), and the lower 16 bits are EDL.
(R).

FIG. 1 shows the relationship between the envelope signal ED and the amplitude level of the envelope-added musical sound waveform.

The musical tone signal and the lower envelope signal are multiplied by the EDL, and the result of the multiplication is shifted in -6 dB steps using the upper envelope signal EDU, and an attenuation envelope is added.

The equation below shows the calculation formula for obtaining the sample value of the envelope-added sound waveform.

f(x, e)=f(x)/2 ^q −1/2 ^q+1・r/2 ^R・f
(x) ...(1) q (q ₃ q ₂ q ₁ q ₀ ; binary integer) represents the upper envelope signal EDU.

(q=0, 1, 2, . . . 2 ^Q-1 ; Q=4) r (r _R-1 . . . r ₁ r ₀ ; binary integer) represents the lower envelope signal EDL.

(r=0, 1, . . . 2 ^R-1 ; R=16) Envelope ED is generated by performing the calculation ED=ED _-1 +ΔED at regular intervals.

FIG. 2 shows a block diagram for realizing envelope addition in equation (1).

In Fig. 2, 1 is a waveform generator that generates a musical sound waveform, 2 is a register that stores the envelope signal ED, 3 is an increment register that stores the incremental value ΔED, 4 is an adder, and 5 is a controller that controls the state of the envelope signal. 6 is a multiplier, 7 and 8 are shifters,
Reference numeral 9 represents an inversion gate that performs logic inversion, 10 represents negative input data, and 11 represents an adder.

Here, the waveform generator 1 will be described. The waveform generation section 1 includes a data memory section that stores a plurality of waveforms and control data used when generating a composite waveform using the waveforms, and a data readout section that sequentially reads out the control data and waveforms and repeatedly reads out the final waveform. and a waveform calculation unit that generates a composite waveform sample using the control data and waveform sample data read by the data reading unit,
It has an interpolation section in which the synthesized waveform generated by the waveform calculation section is sequentially read out to generate the synthesized waveform, and a hold section in which the final waveform is repeatedly read out and generated in the synthesized waveform, and the waveform changes (timbre change) at the rising edge of the musical tone. is approximated by an interpolation interval, and a stable waveform in the stationary part of a musical tone is approximated by a hold interval to generate a musical sound waveform. equipment”.

In FIG. 2, an adder 4 adds the envelope signal ED stored in the register 2 and the increment value ΔED stored in the increment register 3 at regular intervals. The calculation result is then supplied to the multiplier 6 and shifters 7 and 8 via the gate 5, and is also stored in the register 2 as a new envelope signal ED.

The gate 5 operates in the following three operating states.

(i) When the key switch is on When the key switch is on, the output of gate 5 is always (0) ₁₀ . As a result, multiplier 6
(0) ₁₀ is supplied to adder 1.
The output signal ADD of 1 is ADD=f(x);(f
(x) is the output signal of the waveform generator 1).

(ii) When the key switch changes from on to off In this case, the result of addition processing performed by adder 4 appears at the output of gate 5. That is, envelope addition processing is performed.

(iii) When the envelope signal EDU mentioned above becomes (111) ₂ When the signal EDU becomes (1111) ₂ , all bits (20 bits) of the envelope signal ED are always “1”.
shall be. As a result, generation of musical tone signals is stopped.

The musical tone signal f(x) generated by the waveform generator 1 is multiplied by the lower envelope signal EDL(r) in the multiplier 6, and the upper 16 bits of the multiplication result are sent to the shifter 8.
supply to. Then, the shifter 8 performs shift processing based on the upper envelope signal EDU(q), and supplies the shift result to the adder 11 via the inverting gate 9. The output signal of shifter 8 is (1)
This corresponds to the 1/2 ^q+1・r/2 ^R・f(x) term in the equation.

Also, the musical tone signal f(x) generated by the waveform generator 1
is also supplied to the shifter 7, which performs shift processing based on the upper envelope signal EDU(q) and supplies the shift result to the adder 11. The output signal of the shifter corresponds to the f(x)/ ^2q term in equation (1).

Addition processing is then performed in the adder 11 to obtain a musical sound waveform to which an attenuation envelope has been added.

Next, from the starting point of adding the envelope,
The relationship between the time until the generation of musical tones stops will be described.

Assuming that the adder 4 performs addition processing every 22 μS, the envelope time T _ENV is T _ENV = (2 ⁴ −1) 2 ¹⁶ /ΔED×22 μS (2).

ΔED is an increment value stored in the increment register 3.

For example, if ΔED = 1, T _ENV is 21.6S, if ΔED = 2, T _ENV = 10.8S, and if ΔED = 64, T ENV is 21.6S.
It becomes 337.5mS.

Although two adders 4 and 11 and two shifters 7 and 8 are provided in FIG. 2, they can be reduced to one each by performing time-sharing processing.

FIG. 3 is a block diagram of another embodiment of the present invention.
Components having the same functions as those in FIG. 2 are designated by the same reference numerals and their explanations will be omitted.

The configuration shown in FIG. 3 embodies a simplified version of the envelope addition calculation formula shown in equation (1).

Equation (7) shows a simplified envelope addition calculation equation.

f(x, e)=f(x)/2 ^q −1/2 ^q+1・r/2 ^R・f
(x) = f(x)-r/2f(x)1/2 _R /2 ^q = (2 ^R -r/2)-f(x)/2 _R /2 ^q (2 ^R -r /2) term is 2 ^R = 1 + _R-1 〓 ⁱ⁼⁰ 1.2 ⁱ = 1 + 2 ^R-1 + _R-2 〓 ⁱ⁼⁰ 1.2 ⁱ ...(3) r/2 = _R-1 〓 ⁱ⁼⁰ It can be expressed as r _i・2 ^(r-1) ...(4) (r=r _R-1 ... r ₁ r ₀ ; binary integer (R=16)).

Ignoring r ₀・2 ^-1 (i=0) in equation (4), r/2= _R-1 〓 ⁱ⁼⁰ r _i・2 _(i-1) = _R-2 〓 ⁱ⁼⁰ r _{i+ 1}・2 ⁱ ……(5).

Expressing 2 ^R − r/2 using equations (3) and (5), 2 ^R − r/2=1+2 ^R-1 + _R-2 〓 ⁱ⁼⁰ 1.2 ⁱ − _R-2 〓 ^{i= 0} r _i+1・2 ⁱ =1+1.2 ^R-1 + _R-2 〓 ⁱ⁼⁰ (1−r _i+1 )・2 ⁱ ...(6).

_{The R-2} 〓 ⁱ⁼⁰ (1−r _i+1 )・2 ⁱ term in equation (6) is ( _R-1 ... _{2 1} ;
(binary integer).

As a result, f(x, e) is f(x, e)≒(1.2 ^(R-1) +r/-')・f(x)・1
/2 _R /2 ^q
...(7) It can be approximated as [′= _R-1 ... _{2 1} ; binary integer].

In FIG. 3, the envelope signal ED stored in the register 2 is added to the increment value ΔED in the adder 4 at regular intervals, and is incremented.

The lower envelope signal EDL (16-bit configuration) is supplied to the multiplier 6 via the inverting gate 9. The relationship between the input and output signals of the inversion gate 9 is as follows:
It will look like this:

Input = r, output = 1・2 ^(R-1) +' In other words, input signal r(r ₁₅ (MSB), r ₁₄ , r ₁₃ ,
..., r ₂ , r ₁ , r ₀ (LSB) are shifted one bit to the right (r ₁₅ → r ₁₄ , r ₁₄ → r ₁₃ , r ₁₃ → r ₁₂ , ..., r ₂ → r ₁ , r ₁
→ r ₀ , r ₀ is rounded down). Then, by inverting the shift result (r→) and keeping the most significant bit r ₁₅ always at “1” (1·2 ^(R-1) ), the output signal (1·2 ^(R-1) +′ ).

The multiplier 6 multiplies the musical tone signal f(x) generated by the musical tone generating section 1 by the output signal of the inversion gate 9, and transfers the upper 16 bits of the multiplication result to the shifter 7.
supply to. Multiplier 6 is 16 bits x 16 bits = 32
It has a bit structure, and by using only the upper 16 bits, it is equivalent to performing (1/2 ^R = 1/2 ¹⁶ ) processing.

Then, the shifter 7 transmits the multiplication result to the upper envelope signal EDU (4 bits; 1/2 ⁰ , 1/2 ¹ , ..., 1/2 ¹⁴ , 1/2 ¹⁵ = sound generation is stopped and the output is always discarded). Shift processing is performed based on the value (becomes “0”),
Calculate the attenuation envelope added musical sound waveform f(x, e).

FIG. 4 is a block diagram of another embodiment of the present invention.

Components with the same functions as those in FIG. 3 are given the same reference numbers and their explanations are omitted.

In FIG. 4, reference numeral 12 represents a step data generation section.

In the case of the embodiment shown in Fig. 3, the envelope signal ED
The increment value ΔED used when performing the increment process is constant, but in the embodiment shown in FIG.
The upper envelope signal EDU stored in the signal EDU is supplied to the incremental data generating section 12, and the incremental value ΔED _(q) based on the signal EDU is supplied from the incremental data generating section 12 to the adder 4. , the increment value ΔED changes depending on the signal EDU.

As a result, the tendency of the attenuation envelope shown in FIG. 1 can be adjusted in steps of 6 dB, and an envelope characteristic with a break point can be realized.

FIG. 5 is a block diagram of another embodiment of the present invention.

Components with the same functions as those in FIG. 3 are designated by the same reference numerals and their explanations will be omitted.

In FIG. 5, 13 is a level register that stores level data for setting the amplitude level of musical tones;
14 is a gate.

In the gate 5 shown in FIG. 2, when the key switch is in the on state, the output of the gate 5 is always (0) ₁₀ , but in the case of the gate 14, the level data LD stored in the level register 13 is output. It has become a constant choice. As a result, the envelope signal ED=level data LD, and when the key switch is in the on state, a musical tone signal having an amplitude level corresponding to the level data LD is obtained from the output of the shifter 7.

Then, when the key switch changes from on to off, the envelope signal is incremented similarly to the gate 5. In this case, stepping is performed from the position set by the level data LD.

Then, similarly to gate 5, when the upper envelope signal EDU becomes (1111) ₂ , from then on, all bits (20 bits) of the envelope signal ED are always set to "1".
shall be. As a result, generation of musical tone signals is stopped.

The relationship between level data LD and amplitude level will be described.

The level data LD has an 8-bit configuration (LD ₇
(MSB), LD ₆ , ..., LD ₁ , LD ₀ (LSB), and the relationship with the envelope signal ED is LD ₇
= ED ₁₉ , LD ₆ = ED ₁₈ , LD ₅ = ED ₁₇ , ...LD ₁ =
ED ₁₃ , LD ₀ =ED ₁₂ .

ED ₁₉ to _{ED 16} are upper envelope signals EDU (Q ₃ ,
Q ₁ , Q ₂ , Q ₀ ).

ED ₁₅ ~ ED ₁₂ are lower envelope signals EDL
( _R15 (MSB), _R14 , _R13 ,..., _R1 , _R0 (LSB))
Corresponds to bit positions R ₁₅ to R ₁₂ of .

As a result, the amplitude level setting step is -
6dB/2 ⁴ = -0.375dB step. In this way, when the key switch is on, the envelope signal
Since ED=level data LD, the amplitude level of musical tones can be easily controlled without providing a separate multiplier or the like for amplitude level control.

FIG. 6 shows the on/off state of the key switch and the envelope signals of organ-type musical tones and piano-type musical tones.

In FIG. 6, 1 represents the on/off state of the key switch. 2 represents an organ type envelope signal, and 3 represents a piano type envelope signal.

In the case of organ-type musical tones, if the key switch is on, the envelope signal is always (0) ₁₀ or the level data LD stored in the level register 14. When the key switch changes from on to off, it starts stepping the envelope signal, and when the upper envelope signal EDU reaches (1111) ₂ , it stops stepping and generates an envelope signal that stops the generation of musical tones. do.

In the case of a piano-type musical tone, when the key switch changes from the off state to the on state, the envelope signal is initialized to (0) ₁₀ or the level register 14 is set.
Set the level data LD to be stored, and then
Step processing of the envelope signal is performed, and when the upper envelope signal EDU reaches (1111) ₂ , the step processing is stopped and the generation of musical tones is stopped. Generates an envelope signal.

In the embodiments shown in FIGS. 2 to 5, the increment value ΔED is of one type or the upper envelope signal.
Although it varies depending on the EDU, a plurality of increment values ΔED ₁ , ΔED ₂ , ..., ΔED _N are prepared, and a predetermined increment value ΔED is selected from the above-mentioned increment values ΔED ₁ to ΔED _N. By adopting a configuration that performs advance processing, it is possible to control the time of the attenuation envelope.

Furthermore, by storing different increment values in the increment register 3 depending on the attenuation envelope characteristics, it is possible to control the attenuation envelope time in the same way as described above.

Effects of the Present Invention As explained above, the envelope adding device of the present invention includes a waveform generation section that generates a musical sound waveform, an envelope generation section that performs stepping processing at predetermined time intervals to generate an envelope signal, and a multiplication section. , and a shifter section, divides the envelope signal into two groups, upper and lower, and multiplies the output signal of the waveform generator by the lower envelope signal in the multiplication section, and converts the multiplication result into the upper envelope signal. By performing shift processing on the basis of the envelope signal in the shifter section, a musical waveform with an envelope added is obtained.The envelope generating section includes an envelope register for storing an envelope signal, an increment register for storing an increment value, an adder, etc. The envelope signal is incremented by adding the envelope signal in the envelope register and the increment value in the increment register at predetermined time intervals. Since the envelope is added by performing multiplication and shift processing with , a huge amount of envelope can be added. In addition, if a multiplication means is present in the waveform generation section, the circuit size can be further reduced by using the multiplication section for adding an envelope and for the waveform generation section in a time-sharing manner, making it suitable for LSI implementation. This is the circuit configuration.

Furthermore, the present invention includes a waveform generation section that generates a musical sound waveform, an envelope generation section that performs step processing at predetermined time intervals and generates an envelope signal, and a step data generator that generates step data based on the envelope signal. The envelope signal is divided into two groups (upper and lower), the multiplication section multiplies the output signal of the waveform generation section and the lower envelope signal, and the multiplication section includes a multiplication section, a multiplication section, and a shifter section. The result is shifted in the shifter section based on the upper envelope signal to obtain a musical sound waveform with an envelope added.Since the step data can be adjusted according to the contents of the envelope signal, there is no bending. Envelope characteristics with points can be easily realized.

Furthermore, the present invention includes a waveform generation section that generates a musical sound waveform, a level setting section that sets the amplitude level of the generated musical sound waveform, and a step-up process that is performed at predetermined time intervals based on the amplitude level set by the level setting section. The envelope signal is divided into two groups (upper and lower), and the multiplication section generates the output signal of the waveform generation section and the lower envelope signal. By performing a shift process on the multiplication result in the shifter section based on the upper envelope signal, a musical sound waveform with an envelope added is obtained, and a musical sound waveform having the amplitude level set in the level setting section is obtained. When the key switch is on, the envelope signal is made equal to the amplitude level data set in the level setting section, and the envelope signal is incremented from that amplitude level to generate an envelope signal based on the amplitude level. Therefore, there is no need to separately provide a multiplier or the like for amplitude level control, the amplitude level of musical tones can be easily controlled, and an envelope can be added based on the amplitude level.

[Brief explanation of the drawing]

1 and 6 are explanatory diagrams of the operation of the present invention, and
3, 4, and 5 are configuration diagrams of embodiments of the present invention, respectively. 1... Waveform generator, 2... Register, 3... Increment register, 4... Adder, 5... Gate, 6...
... Multiplier, 7, 8 ... Shifter, 9 ... Inversion gate, 10 ... Carry input data, 11 ... Adder, 12 ... Step data generation section, 13 ... Level register, 14 ... Gate.

Claims (1)

[Scope of Claims] 1. A waveform generating section that generates a musical sound waveform, an envelope generating section that performs step processing at predetermined time intervals and generates a 20-bit envelope signal, a multiplier section, and a shifter section, The envelope signal is divided into two groups, the upper 4 bits q and the lower 16 bits γ, and the multiplication section multiplies the output signal of the waveform generation section and the lower envelope signal, and the multiplication result is multiplied based on the upper envelope signal. An envelope adding device characterized in that a musical sound waveform to which an envelope is added is obtained by multiplying by 1/2q+1 in the shifter section. 2. A waveform generation section that generates a musical sound waveform, an envelope generation section that performs step processing at predetermined time intervals and generates a 20-bit envelope signal, and a step data generation section that generates step data based on the envelope signal. , a multiplier section, and a shifter section, the envelope signal is divided into two groups of upper 4 bits q and lower 16 bits γ, and the multiplication section multiplies the output signal of the waveform generation section and the lower envelope signal. The above multiplication result is multiplied by 1/2q+1 based on the upper envelope signal in the shifter section to obtain a musical sound waveform with an envelope added, and stepwise processing of the envelope signal is performed using stepwise data based on the envelope signal. An envelope adding device characterized in that by doing so, a musical sound waveform having an envelope characteristic having a break point is obtained. 3. A waveform generation section that generates a musical sound waveform, a level setting section that sets the amplitude level of the generated musical sound waveform, and a 20-bit waveform generation section that performs step processing at predetermined time intervals and generates a 20-bit signal based on the amplitude level set by the level setting section. an envelope generator that generates an envelope signal;
It comprises a multiplier and a shifter, divides the envelope signal into two groups of upper 4 bits q and lower 16 bits γ, and multiplies the output signal of the waveform generator by the lower envelope signal in the multiplier. , by performing a shift process on the multiplication result in the shifter section based on the upper envelope signal, a musical sound waveform to which an envelope is added is obtained, and at the same time, a musical sound waveform having an amplitude level set in the level setting section is obtained. Envelope adding device.