JPS6411954B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a volume envelope control device that can effectively prevent click noise generated during digital volume control of the rising and falling edges of a musical sound waveform.

[Prior art]

Conventional volume envelope control devices using digital technology for electronic musical instruments control envelope curves such as attack, sustain, and
A device is known in which time is controlled using a uniquely determined clock for each release state.

FIG. 1 shows an example of this, in which the key code corresponding to a performance key operated on the performance keyboard 1 is output as a corresponding pitch clock signal from the pitch clock generator 3 via the key code memory 2. Specify to do so. This output pitch clock signal is supplied to a binary step counter 4 which counts the quantization steps of one cycle of the musical waveform. The step count value counted by the step counter 4 is associated with the output of the decoder 5, and the tone waveforms stored in advance at each address position in the tone waveform storage section 6 are sequentially counted for each step. is read out. The read output value of the musical sound waveform is supplied to the multiplication circuit 7. On the other hand, the volume envelope is the envelope counter 8.
This is done by controlling the counting state of . This envelope counter 8 is a 5-bit binary counter, and as shown in FIG.
The envelope counter 8 has a count amplitude value of 31 counts), and a state counter 9 consisting of 2 bits is connected in series to the upper part of the envelope counter 8.
The count value of this status counter 9 is the volume envelope clear (key release), attack, sustain,
Each state of the release state is detected, and each state is sequentially associated with a counting state of "00", "01", "10", and "11". Therefore, the state detection circuit 1
0 detects each counting state, and depending on the state, control clocks φ _A , φ _D , φ _R for attack, sustain, and release created based on the basic clock φ ₀ are generated from the clock generation circuit 11. Selectively output. The envelope counter 8 and the state counter 9 are constantly incremented in the upward direction by control clocks φ _A , φ _D , φ _R selected according to each state (see FIG. 2). Further, the state detection output of the state detection circuit 10 is supplied to the multiplication circuit 7 together with the count value of the envelope counter 8.

That is, when the state detection circuit 10 detects an attack state, the count value of the envelope counter 8, which is incremented by the clock _φA , directly becomes the volume control value, and when it detects a sustain state, the envelope counter 8 is incremented by the control clock _φD , the amplitude value of "31" is always the volume control value during this sustain state, and if the release state is detected, A complementary value obtained by inverting the counting state of the envelope counter 8, which is incremented by the control clock _φR , becomes the volume control value. These volume control values and the readout output value of the musical sound waveform are multiplied in a multiplication circuit 7. The output of this multiplier circuit 7 is supplied to an accumulator 13 via an adder 12. The output of the accumulator 13 is fed back to the adder 12, where it is subjected to accumulation control, and then sent to a D/A (digital-to-analog) converter 14.
The sound is output from the speaker 16 via the filter 15.

[Conventional problems]

By the way, depending on the count value (volume control value) output from the envelope counter 8, the waveform storage unit 6
When volume envelope control is performed while increasing or decreasing the volume level of the musical waveform data output from the envelope counter 8, as shown in FIG. If the timing of the change in the volume control value (indicated by the broken line Y in FIG. 10) is not performed at an appropriate position, the tone waveform will change at the change in the volume control value (indicated by the broken line Z in FIG. 10). The amplitude value of data X may change rapidly. As described above, when the amplitude value of the musical waveform data X suddenly changes, there is a problem in that clicking noise is generated.

[Purpose of the invention]

The present invention has been made in view of these conventional problems, and is intended to reliably prevent the occurrence of click noise that may occur when envelope-controlling the volume level of musical waveform data according to a volume envelope control value. The purpose is to prevent.

[Key points of the invention]

In order to achieve these objectives, the present invention makes it possible to change the volume envelope control value in synchronization with the arrival of a specific address position where the amplitude value of the read musical waveform data becomes 0 level. The main point is that envelope control is performed while increasing or decreasing the volume level of the read musical sound waveform data according to the changed volume envelope control value.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

The key code corresponding to the performance key operated on the performance keyboard 100 is held in the key code memory 101.
The key code stored in the key code is supplied to the pitch clock generator 102 to select the corresponding pitch clock signal. Pitch clock generator 102
The pitch clock signal output from the 5-bit step counter 103 is applied as a counting step signal. This step counter 103 is
It obtains ``32'' (0 to 31) counting states for carving out quantization steps for one cycle of a musical sound waveform.
For each 5-bit output, the decoder 104 sequentially generates an output signal at each counting step as an output of "32", and this output signal causes the tone waveform storage unit 105
Tone waveform data is read from. The tone waveform storage unit 105 digitizes the value of each step in accordance with the tone waveform shape shown in FIG. 4, for example.
It is configured by being fixedly stored in ROM (read-only memory) in advance. Alternatively, this can be done by selecting a switch at each step to specify a numerical value corresponding to the tone waveform shown in FIG. and,
The output values (tune waveform data) sequentially read from the tone waveform storage section 105 at each step are supplied to the multiplication circuit 106. This multiplication circuit 106 is
A value obtained by multiplying the count value read from the envelope register 107 by the output value read from the tone waveform storage section 105 is output. This envelope register 107 has 5 bits (0
It consists of a binary register with a count status of .about.31, and a status register 108 with a 2-bit configuration is further connected in series above the binary register. The contents of this status register 108 include clearing (key release), attack, and clearing of the volume envelope curve as shown in FIG.
In order to detect each state of sustain and release, the envelope register 107 is incremented each time it goes through one cycle. The count state of the state register 108 is decoded by a state detection circuit 109, and a corresponding state detection signal is supplied to the multiplication circuit 106 as a control signal. That is, when an attack state is detected, the count value of the envelope register 107 is supplied to the multiplication circuit 106 as a volume control value. Further, when a sustain state is detected, regardless of the count increment of the envelope register 107, the maximum amplitude value "31" is supplied to the multiplier circuit 106 as a volume control value as the sustain state of the envelope. Additionally, if a release state is detected, the envelope register 107
A complement value obtained by inverting the 5-bit output value of is supplied to the multiplier circuit 106 as a volume control value. Then, the volume control value that controls the count value of the envelope register 107 to be in the attack, sustain, and release states as described above is the output value for each step (music waveform data ) is multiplied by the multiplication circuit 106.

The 5-bit output of the envelope register 107 is provided to an adder 110. This adder 1
When the step counter 103 counts "0" from the decoder 104, a "0" step detection signal is applied to the signal 10 as a "+1" addition signal. Therefore, "+1" is added to this adder 110 every cycle in synchronization with the arrival of the "0" step of one cycle of the tone waveform. The output value to which "+1" has been added by the adder 110 is input to the envelope register 107 again. As a result, the step counter 10
The control value of the envelope register 107 increases by "1" in synchronization with the arrival of the "0" step in every cycle of "3". Then, the output value of the multiplication circuit 106 is supplied to the accumulator 112 via the adder 111, and the output of the accumulator 112 is fed back to the adder 111 and accumulated. ) The sound is output from the speaker 115 via the conversion circuit 113 and filter 114 in this order.

According to the above configuration, pitch clock signals corresponding to the performance keys operated on the performance keyboard 100 are outputted from the pitch clock generation section 102 and counted by the step counter 103. When a performance key is operated, the status register 108 is set from a clear state of "00" to "01" indicating an attack state. When this attack state is set, when the step counter 103 counts "0" steps, the "+1" signal output from the decoder 104 causes the adder 11 to be activated for each cycle of the musical waveform.
If it is 0, "+1" is added. Therefore, the volume control value of the envelope register 107 is sequentially incremented by "+1" for each cycle of the musical tone waveform. Therefore, as shown in FIG. 5, the musical sound waveform shown in FIG. 4 (shown as a simplified linear triangular wave in FIG. The volume level of (a) is multiplied in the multiplier circuit 106 so that it increases with each cycle in which the volume control value of the envelope register 107 increases.

When the envelope register 107 reaches the count state of "11111", the state register 108 is set to the suspension line state of "10". When this sustain state is reached, the envelope register 107 is again incremented from the "00000" counting state every cycle as in the above case, but the state detection circuit 107
Since the sustain state detection signal from 09 is supplied to the multiplication circuit 106, the volume control value is apparently controlled to be in the counting state of "11111" indicating the maximum amplitude value. Therefore, during the sustain period, the volume control value multiplied by the readout output value of the tone waveform is the same value. Then, when the volume control value of the envelope register 107 becomes "11111" indicating the maximum amplitude value again, the status register 108 becomes "11".
The release status will be set to . When the release state is detected, the envelope register 107 is incremented every cycle from the state of "00000" in synchronization with the arrival of the counting time of the "0" step. Since the level is in a decreasing direction, the volume control value is controlled to be the complement value of "11111" of the relevant count value of the envelope register 107. For this reason, the sixth
As shown in the figure, contrary to the case of the attack state, the volume level gradually decreases for each "1" count from the maximum amplitude value "11111" in the direction of "00000". Note that such an operation is possible because the frequency of the pitch clock signal generated by the pitch lock generating section 102 differs for each performance key, and the one cycle period of the step counter 103 also changes. Curve attack, sustain,
The time of each release state is random according to the one cycle period.

3 to 6, when the step counter 103 counts "0" steps, a "+1" signal is added to the adder 110 in synchronization with the output of the "+1" signal output from the decoder 104, and this result ,
The volume control value of the envelope register 107 is “+”
An example in which the count is incremented by "1" has been described, but as another example, as shown in FIG. You may also do so.

That is, when a signal is generated that is synchronized with the step count of "0" of the step counter 103 outputted from the decoder 104, the addition value selection circuit 116
A predetermined addition value set in advance, for example, a code "10" of "2" is added to the corresponding count value represented by 5 bits of the envelope register 107. If you configure it like this,
For each “0” step of the step counter 103,
The volume control value of the envelope register 107 is
The count is incremented by "+2". Therefore, especially in the attack state, the rising angle within the rising time (attack time) can be increased (high attack), and conversely, in the release state, the falling angle within the falling time (release time) can be increased. can be made large (high release).
Furthermore, Figure 8 shows the high release state.
This shows a state in which musical waveform data is multiplied and controlled by a volume control value that rapidly decreases by 2 every cycle.

As described above, in this embodiment, when a specific address position at which the amplitude value of the musical sound waveform data (indicated by X in FIG. A in Figure 9
point), the volume control value read from the envelope register 107 is sequentially increased or decreased by the adder 110 as shown by the broken line Y in the figure in synchronization with the arrival of the volume control value. When the control value is increased or decreased, the volume level of the musical sound waveform X does not change suddenly, and therefore it is possible to prevent click noise from occurring.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when a specific address position arrives at which the amplitude value of the tone waveform data read out from the tone waveform storage means by the reading means reaches the 0 level, the timing is synchronized with the arrival of the specific address position. Since the volume control value read from the volume envelope control value storage means can be changed, it is possible to prevent the amplitude value of the musical waveform data from changing suddenly at the time of changing the volume control value. This can be reliably prevented, and therefore, the generation of click noise can be prevented.

[Brief explanation of the drawing]

FIG. 1 is an overall circuit configuration diagram explaining the configuration of a conventional volume envelope control device, FIG. 2 is a diagram showing a volume envelope explaining FIG. 1, and FIG. 3 is an overall circuit diagram of the volume envelope control device of the present invention. 4 is a musical sound waveform diagram used to explain FIG. 3, FIG. 5 is an explanatory diagram of the operation in the attack state according to FIG. 3, FIG. 6 is an explanatory diagram of the operation in the release state, and FIG. 8 is a diagram illustrating the overall circuit configuration of another embodiment of the present invention, FIG. 8 is an explanatory diagram of the operation in the released state according to FIG. 7, and FIG. 9 is a diagram illustrating the envelope control state by the volume envelope control device of the present invention. , FIG. 10 is a diagram showing an envelope control state by a conventional volume envelope control device. 100... Performance keyboard, 101... Key code memory, 102... Pitch clock generator, 103...
Step counter, 104...decoder, 105...
Musical sound waveform storage unit, 106...Multiplication circuit, 107...Envelope register, 108...Status register, 1
10... Adder.

Claims (1)

[Scope of Claims] 1. Pitch data generation means for generating pitch data corresponding to a specified pitch; Musical sound waveform storage means for digitally storing musical sound waveform data for each of a plurality of address positions; reading means for reading out the musical sound waveform data stored in the musical sound waveform storage means at a speed based on the pitch data generated by the pitch data generating means; and an envelope control value storage for readably storing a volume envelope control value. means, a volume envelope read from the volume envelope control value storage means in synchronization with the arrival of a specific address position at which the amplitude value of the musical waveform data read by the reading means reaches 0 level; volume envelope control value changing means for enabling a control value to be changed and sending the changed volume envelope control value to the volume envelope control value storage means; As the stored volume envelope control value changes over time, outputs specification information for specifying the rising and falling states of the volume envelope in order to form a specific volume envelope shape. and an envelope state designation information output means for outputting the volume envelope control value in a state in which the rising and falling states of the volume envelope are sequentially designated by the designation information output from the envelope state designation information output means. Due to the envelope control value stored in the means,
A volume envelope control device comprising: volume envelope control means that performs envelope control while increasing or decreasing the volume level of the musical sound waveform data read from the musical sound waveform storage means.