JP2016142962A - Program and waveform generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress unintended variation in pitch of output waveform data even when the output waveform data is generated based upon phase information having been subjected to modulation processing whose processing contents dynamically change.SOLUTION: A waveform generation device inputs second phase information to a waveform information acquisition part 204, the second phase information being obtained by correction using a correction value Adj for correcting a deviation in varying period of first phase information, caused by modulation using a modulation value Mod, on the first phase information and modulation using the modulation value Mod when the waveform generation device is provided with a waveform information acquisition part 204 which generates, as waveform information, a sample value corresponding to input phase information based upon the input phase information, a phase counter 201 which generates the first phase information based upon supplied frequency information, and an addition part 203 which modulates the first phase information using the modulation value Mod calculated by a modulation value arithmetic part 205 based upon the waveform information generated by the waveform information acquisition part 204.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a program for realizing a function of generating waveform information in a computer, and a waveform generation apparatus having a function of generating waveform information.

  Conventionally, by generating phase information for each sample period according to the specified pitch, reading the value of the sine wave table corresponding to the phase information and outputting it as waveform data for each sample period, the musical sound of the specified pitch A technique for outputting waveform data according to the above is known.

  In this technique, as described in Patent Document 1, it is known to modulate phase information by feeding back waveform data read from a sine wave table to generated phase information. By reading the values of the sine wave table corresponding to the phase information subjected to such modulation, it is possible to output waveform data of a complicated waveform.

JP 2001-175264 A

  However, when the modulation described in Patent Document 1 is performed, the change in the phase information before the modulation is caused by the time required for the process necessary for the modulation, for example, the process for calculating the modulation amount based on the read waveform data. There is a difference between the period and the change period of the phase information after modulation. This deviation is shown in FIG. 4, for example. The solid line indicates the change period of the phase information before modulation, and the dotted line indicates the change period of the phase information before modulation.

When such a deviation occurs, the phase of the output waveform data when the output waveform data is acquired using the phase information after modulation is the case where the output waveform data is acquired using the phase information before modulation. The output waveform data will be out of phase.
In the conventional apparatus as described in Patent Document 1, the content of the modulation process is constant, and the modulation process that causes a large phase shift is not performed. It was.

However, the magnitude of this phase shift will change accordingly if the content of the modulation process changes. For this reason, when the contents of the modulation process are changed dynamically, the phase of the output waveform data also changes in accordance with the change, and the pitch of the output waveform data is also intended due to the Doppler effect accompanying the phase change. The problem of changing without causing arises.
Further, even when a table other than the sine wave table is used for acquiring the output waveform data based on the phase information, or when a means other than the table is used, the same problem can occur.

  The present invention has been made in view of such circumstances, and an unintended pitch in output waveform data even when generating output waveform data based on phase information subjected to modulation processing whose processing contents change dynamically. The purpose is to be able to suppress changes in

  In order to achieve the above object, according to the present invention, a computer generates a first phase based on the supplied frequency information, waveform generating means for generating, as waveform information, sample values corresponding to the phase information based on the input phase information. A phase information generating means for generating information; a modulating means for modulating the first phase information using the waveform information generated by the waveform generating means; and a shift in a fluctuation cycle of the phase information caused by the modulation by the modulating means. Correction program for correcting and program for causing the waveform generation means to function as input means for inputting second phase information obtained by adding modulation by the modulation means and correction by the correction means to the first phase information I will provide a.

In such a program, the correction means detects the difference between the phase information before and after the modulation when the phase information after the modulation by the modulation means reaches a predetermined value, and detects the difference between the fluctuation periods. Therefore, it is preferable to correct the phase information before modulation by the modulation means.
Alternatively, the correction means detects a difference between the first phase information and the second phase information when the second phase information reaches a predetermined value, and adjusts the correction amount of the phase information by the difference. The phase information is preferably corrected by the correction amount after the adjustment.

Furthermore, the correction means may be provided with means for making the time change of the correction amount related to the correction slower than the time change of the detected shift amount of the fluctuation period.
Further, the present invention can be implemented in any mode such as an apparatus, a system, a method, a recording medium, etc., in addition to being implemented as a program as described above.

  According to the above configuration, even when output waveform data is generated based on phase information that has been subjected to modulation processing whose processing contents change dynamically, an unintended pitch change in the output waveform data can be suppressed.

It is a figure which shows the hardware constitutions of the waveform generation apparatus which is one Embodiment of this invention. It is a figure which shows the structure of the function which concerns on the production | generation and output of the waveform data in the waveform generation apparatus shown in FIG. It is a figure which shows the function structure of the waveform generation part shown in FIG. 2 in detail. It is a figure which shows the example of a time-dependent change of 1st phase information in the state which does not correct | amend by the addition part 202, and 2nd phase information obtained by modulating 1st phase information. Changes in the temporal value of the phase value output by the phase counter 201, the first phase information corrected by the adding unit 202, and the second phase information obtained by modulating the corrected first phase information by the adding unit 203 It is a figure which shows an example. It is a flowchart which shows the process corresponding to the function of the waveform generation part 131 shown in FIG. It is a figure corresponding to FIG. 3 which shows the function structure of the waveform generation part 131 in the modification of embodiment of this invention.

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.
First, FIG. 1 shows a hardware configuration of a waveform generation apparatus according to an embodiment of the present invention.
As shown in FIG. 1, the waveform generation device 10 includes a CPU 11, a ROM 12, a RAM 13, an HDD (hard disk drive) 14, a DMA (direct memory access) control unit 15, a DAC (digital / analog converter) 16, and an external device I / F. (Interface) 17, display circuit 18, detection circuit 19, and communication I / F 20 are provided, and these are connected by a system bus 21.

Among these, the CPU 11 is a control unit that performs overall control of the operation of the waveform generation apparatus 10 and executes a necessary control program stored in the ROM 12 or the HDD 14 to control each unit of the waveform generation apparatus 10 to be described later. Various functions including a waveform generation function are realized.
The ROM 12 and the HDD 14 are rewritable nonvolatile storage means for storing a control program executed by the CPU 11 and data that should remain even after the power is turned off.
The RAM 13 is storage means used as a work memory for the CPU 11.

The DMA control unit 15 has a function of accessing data stored in the RAM 13. For example, the DMA control unit 15 generates digital waveform data (audio) generated by the functions of a sequencer application (hereinafter referred to as “application”) 110 and software synthesizer plug-in 120 executed by the CPU 11 and stored in the RAM 13. (Data) is output from the DAC 16 and used for sound generation, the waveform data is transferred from the RAM 13 to the DAC 16 over time.
The DAC 16 has a function of converting digital waveform data into an analog sound signal and outputting the analog sound signal to an external sound system (sound generation means) such as a speaker.

  The external device I / F 17 is an interface for connecting an external device to the waveform generation device 10, and for example, an USB (Universal Serial Bus) standard interface can be adopted. It is conceivable that a MIDI device that generates MIDI (Musical Instrument Digital Interface: registered trademark) data is connected to the external device I / F 17 and MIDI data is input from here. Also, an audio device is connected to the external device I / F 17, and the waveform data generated by the CPU 11 is output from the external device I / F 17 to the audio device in place of the output from the DAC 16 to generate sound. Is also possible.

The display circuit 18 is an interface for connecting display means such as a display and causing the display means to perform display under the control of the CPU 11.
The detection circuit 19 is an interface for connecting an operation means for receiving an operation from a user such as a keyboard or a mouse, detecting an operation received by the operation means and supplying the operation to the CPU 11.

The communication I / F 20 is an interface for communicating with an external device via a network such as a LAN (local area network).
The above waveform generation device 10 can also be configured using a general-purpose PC (personal computer) as hardware.

A characteristic feature of the waveform generation apparatus 10 described above is a function of generating waveform data (hereinafter simply referred to as “waveform data” when referring to digital waveform data) based on designated frequency information. Hereinafter, this point will be described.
First, FIG. 2 shows a configuration of functions related to generation and output of waveform data in the waveform generation apparatus 10.

As shown in FIG. 2, the waveform generation apparatus 10 includes a MIDI driver 101, an audio driver 102, a sequencer application 110, and a software synthesizer plug-in 120 as functions related to generation and output of waveform data.
Among these, the MIDI driver 101 has a function of acquiring a MIDI event transmitted from an external device connected to the external device I / F 17 and passing it to various applications operating on the OS (Operating System). The audio driver 102 has a function of outputting waveform data generated by various applications to the outside via the DAC 16 or the external device I / F 17. These MIDI driver 101 and audio driver 102 are functions provided by the OS.

The sequencer application 110 has a function of generating and outputting waveform data corresponding to a MIDI event using the software synthesizer plug-in 120.
More specifically, the sequencer application 110 passes the received MIDI event to the software synthesizer plug-in 120, starts generating waveform data, and receives the waveform data generated and output by the software synthesizer plug-in 120 accordingly. To the audio driver 102. At this time, the sequencer application 110 requests waveform data samples from the software synthesizer plug-in 120 at such a frequency and number of samples that the audio driver 102 can output waveform data without interruption (for example, about 300 samples every 5 milliseconds). To do. The software synthesizer plug-in 120 generates waveform data in response to this request and passes it to the sequencer application 110.

  Note that the MIDI events that the sequencer application 110 passes to the software synthesizer plug-in 120 include, for example, a note-on event that instructs the start of sound generation and a note-off event that instructs the sound generation to stop. There is also an event for instructing a change in the value of a waveform parameter that defines the waveform.

Such a MIDI event can be generated by the sequencer application 110 playing back performance data in the SMF (Standard MIDI File) format under timer control, and the MIDI event input from the external MIDI device to the waveform generator 10. Events can also be acquired from the MIDI driver 101.
The functions of the sequencer application 110 as described above can be provided by, for example, a DAW (Digital Audio Workstation) application having a sequencer function.

The software synthesizer plug-in 120 is a function provided by a dynamic link library used by the sequencer application 110, and has a function of generating waveform data in accordance with a MIDI event passed from another process and returning it to the requesting process.
More specifically, the software synthesizer plug-in 120 includes functions of an event handler 121, a pitch generation unit 122, an envelope signal generation unit 123, an operator 124, and an output unit 125.

  Of these, the event handler 121 detects that a MIDI event has been sent from an application using the software synthesizer plug-in 120 such as the sequencer application 110, receives the event, and performs processing corresponding to the event to the software synthesizer plug-in. The function to instruct each part in 120 is provided.

  For example, when the event handler 121 detects a note-on event, it notifies the pitch generator 122 of the note number that represents the pitch to be generated and instructs the pitch generator 122 to start generating frequency information. Pronunciation) Velocity representing the operation speed is transmitted to the envelope signal generator 123 to instruct the start of envelope signal generation. After these instructions, the pitch generator 122, the envelope signal generator 123, and the operator 124 generate waveform data in time series for each sample.

  Further, when the event handler 121 detects an event instructing the change of the value of the waveform parameter, the value of the waveform parameter used by the waveform generation unit 131 of each operator 124 to generate the waveform information according to the information included therein. To change. The waveform parameter includes, for example, a parameter that defines the calculation content of the modulation value in the modulation value calculation unit 205 shown in FIG.

Next, the pitch generator 122 generates frequency information indicating the amount of phase advance in the phase counter 201 of FIG. 3 in one sample period when sounding at the fundamental frequency of the pitch designated by the note number, and the operator 124. The function of supplying to the waveform generation unit 131 is provided.
The envelope signal generation unit 123 generates a control signal indicating a volume corresponding to the velocity, which changes with time as the processing progresses by one sample from the start of sound generation, and supplies the control signal to the volume control unit 132 of the operator 124. It has a function.

  Based on the frequency information supplied from the pitch generator 122, the control signal supplied from the envelope signal generator 123, and the waveform parameters set by the event handler 121, the operator 124 uses the waveform generator 131 and the volume controller. A function of generating waveform data by 132 and supplying the waveform data to the output unit 125 is provided. Of these, the waveform generation unit 131 has a function of generating waveform information based on frequency information and waveform parameters. The volume control unit 132 has a function of generating waveform data to be output by adjusting the amplitude of the waveform information generated by the waveform generation unit 131 according to the control signal.

  A plurality of operators 124 may be provided. In this case, the event handler 121, the pitch generation unit 122, and the envelope signal generation unit 123 supply waveform parameters, frequency information, and control signals to the operators 124 used for sound generation. Further, in addition to or instead of outputting the waveform data output by a certain operator 124 to the output unit 125, it can also be used to modulate the operation of the waveform generation unit 131 of another operator 124. For example, the calculation value of the modulation value in the modulation value calculation unit 205 is adjusted based on the waveform data output by another operator 124.

The output unit 125 has a function of buffering waveform data samples generated by each operator 124 and passing data of the requested number of samples to the application in response to a request from the application.
Note that the processing of the pitch generation unit 122, the envelope signal generation unit 123, and the operator 124 may perform waveform data generation processing in an oversampled unit finer than the sample unit of the output waveform data. In that case, in order to output the waveform data of one sample to the output unit 125, a plurality of cycles are processed, and the result is output.

Next, FIG. 3 shows the functional configuration of the waveform generation unit 131 in more detail.
As shown in FIG. 3, the waveform generation unit 131 includes a phase counter 201, addition units 202 and 203, a waveform information acquisition unit 204, a modulation value calculation unit 205, a timing detection unit 206, a difference calculation unit 207, a switching unit 208, and a correction. A value holding unit 209 and an LPF (low pass filter) 210 are provided.

  Among these, the phase counter 201 includes a function of a phase information generation unit that generates first phase information based on the frequency information supplied from the pitch generation unit 122. In this example, the phase counter 201 adds the value indicated by the frequency information to the current value every time one sample is processed. When the count value exceeds 1, 1 is subtracted from the addition result. As a result, as shown by a solid line in FIG. 4, sawtooth-shaped first phase information is generated that gradually increases from 0 to 1 as time passes and returns to 0 when 1 is reached. Note that the count value at each timing is called a phase value, and the period required for the phase value to change from 0 to 1 corresponds to one cycle of the waveform.

The adding unit 202 has a function of correcting the first phase information output from the phase counter 201 by adding a correction value Adj described later supplied from the LPF 210.
The adding unit 203 has a function of modulating the first phase information corrected by the adding unit 202 by adding a modulation value Mod (described later) supplied from the modulation value calculating unit 205 to generate second phase information.
Each of the addition units 202 and 203 subtracts or adds 1 to the addition result so that the addition result falls within the range of 0 to 1 when the addition result does not fall within the range of 0 to 1.

  The waveform information acquisition unit 204 has a function of a waveform generation unit that receives the second phase information and generates a sample value corresponding to the second phase information as waveform information based on the second phase information. In this example, the waveform information acquisition unit 204 includes a sine wave table storing sine wave sample values corresponding to each phase value, and the sine wave sample values corresponding to the phase values of each sample indicated by the second phase information. Are read out from the sine wave table by performing an interpolation process if necessary, and output as waveform information of the sample. For example, phase value 0 corresponds to phase 0 of a sine wave, phase value 1 corresponds to phase 2π of a sine wave, and so on. The phase value 0 may correspond to the phase -π of the sine wave, the phase value 1 may correspond to the phase π of the sine wave, and so on. The phase of the sine wave may be expressed not by the arc method but by the frequency method.

It is also conceivable that sample values of other waveforms are stored in the table, or waveform information is generated by substituting the phase value into a mathematical formula and calculating.
In any case, the waveform information acquisition unit 204 supplies the generated waveform information to the volume control unit 132 at the subsequent stage and also supplies it to the modulation value calculation unit 205.

The modulation value calculation unit 205 has a function of generating a modulation value Mod for performing feedback modulation on the first phase information using the waveform information generated by the waveform information acquisition unit 204. Then, the function of the modulation means is realized together with the adding unit 203.
The contents of processing such as the calculation for generating the modulation value Mod performed by the modulation value calculation unit 205 are dynamically changed based on the waveform parameters supplied from the event handler (and the waveform data output by other operators 124). Is done. This change may be limited to parameter adjustment, for example, the number of delay samples in the delay processing, or the processing algorithm itself, such as adding or deleting filter processing, switching between absolute value conversion processing and square calculation processing, etc. May be accompanied by changes.

  Here, an example of a calculation processing algorithm for generating the modulation value Mod performed by the modulation value calculation unit 205 will be described. First, the absolute value of the sample value related to the waveform information generated by the waveform information acquisition unit 204 by the absolute value conversion unit After that, the absolute value is input to the low-pass filter, and the output value of the filter is delayed by a predetermined sample by the delay unit. When this process is performed, a certain amount of delay occurs until the sample value input to the modulation value calculation unit 205 in a certain sampling period is reflected in the modulation value Mod supplied to the addition unit 203.

  In any case, by adding the modulation value Mod to the first phase information (after correction in the addition unit 202) in the addition unit 203, the first phase information is modulated to generate second phase information. it can. In this addition, when the phase value is out of the range of 0 to 1 in this addition, 1 is subtracted from the addition result or 1 is added to the addition result so that the phase value after addition falls within the range of 0 to 1. To.

Here, FIG. 4 shows an example of the temporal change of the first phase information (solid line) and the second phase information (dotted line) obtained by modulating the first phase information in a state where the correction by the adding unit 202 is not performed. Indicates. The vertical axis represents the phase value indicated by the phase information in each sample period, and the horizontal axis represents the time expressed in units of the number of samples.
As can be seen from this figure, when the first phase information is modulated using the modulation value Mod reflecting the waveform information generated by the waveform information acquisition unit 204, the fluctuation period (for example, 0) of the second phase information after the modulation is performed. 1 to 1) is shifted from the fluctuation cycle of the original first phase information. This “deviation” corresponds to the fact that the phase of the waveform is shifted by the shift amount D when the state of fluctuation of the phase information is regarded as a waveform.
It has been found by the inventors' simulation that the magnitude of this “deviation” varies depending on the calculation contents in the modulation value calculation unit 205.

  Next, the timing detection unit 206 is a timing when the phase value exceeds 1 at the time of addition by the addition unit 203 (in order to perform a process of subtracting 1 from the phase value at this time, in the graph of FIG. The function of detecting the timing at which fluctuations in value occur). In addition, a function of supplying the phase value of the second phase information before and after the detected timing to the difference calculation unit 207 is provided. Further, at the detected timing, the switching unit 208 is switched to the connected state (1 → 0), and the difference value calculated by the difference calculation unit 207 is stored in the correction value holding unit 209 as the correction preparation value Adjp. The timing detection unit 206 switches the switching unit 208 to an otherwise separated state (otherwise) except for the timing when the phase value exceeds 1, and causes the correction value holding unit 209 to hold the correction preparation value Adjp once held as it is.

  When the phase value of the second phase information is supplied from the timing detection unit 206, the difference calculation unit 207 receives the second value based on the phase value and the phase value of the first phase information before modulation by the addition unit 203. The difference between the phase value of the second phase information and the phase value of the first phase information when the phase value of the phase information becomes “0” is calculated. Since it is rare that the phase value becomes exactly “0” in a certain sampling period, it is usually obtained by performing interpolation using phase values before and after the timing exceeding “1”.

  The obtained difference corresponds to the difference between the phase information before and after the modulation when the phase information after the modulation by the modulation means becomes a predetermined value, and the shift amount of the fluctuation period of the first phase information and the second phase information. The value reflects D. Therefore, it is basically only necessary to correct the first phase information by this difference value, but in this example, the correction value holding unit is used as a means for making the time change of the correction amount slower than the time change of the difference value. 209 and LPF 210 are provided, and correction is performed through these.

The switching unit 208 has a function of supplying the difference value calculated by the difference calculation unit 207 to the correction value holding unit 209 when the connection state and the separation state are switched by the timing detection unit 206 and the connection state is established.
When the difference value is supplied from the difference calculation unit 207 via the switching unit 208, the correction value holding unit 209 holds the difference value as the correction preparation value Adjp until the next time the difference value is supplied. A function of supplying to the LPF 210 every period is provided.

Based on the correction preparation value Adjp for each sampling period supplied from the correction value holding unit 209, the LPF 210 generates a correction value Adj for each sampling period by removing the high frequency component and slowing the time change, and adding the addition unit The function to supply to 202 is provided.
As described above, the adding unit 202 adds the correction value Adj to the phase value of the first phase information and corrects it.
The timing detection unit 206, the difference calculation unit 207, the switching unit 208, the correction value holding unit 209, the LPF 210, and the addition unit 202 constitute a correction unit.

Next, the significance of correcting the phase information by the correcting means will be described with reference to FIGS.
4 is as described above, and FIG. 5 is a diagram illustrating the phase value output from the phase counter 201 (first phase information before correction: solid line) and the first phase information after correction by the adding unit 202 (two-dot chain line). The change over time with the second phase information (dotted line) obtained by modulating the corrected first phase information with the adder 203 is shown on the same axis as FIG.
Here, the purpose of the correction by the addition unit 202 is to eliminate the shift amount D shown in FIG. 4 and to output the fluctuation phase of the second phase information input to the waveform information acquisition unit from the first phase information output by the phase counter 201. This is in accordance with the fluctuation period. Here, the output of the phase counter 201 does not change even when the phase information is modulated or corrected.

  In the configuration of FIG. 3, the difference calculation unit 207 calculates the difference between the phase value of the second phase information and the phase value of the first phase information when the phase value of the second phase information becomes “0”. A difference (in FIG. 5, for the sake of simplicity, the difference itself is assumed to be a correction value Adj) is obtained, and the difference Adj is added to the phase value of the first phase information in each sample period. As a result, phase information whose “phase” is earlier than the original first phase information by the shift amount D can be obtained.

  Then, by modulating the phase information after correction by adding the modulation amount Mod, the second phase information whose “phase” is earlier by the shift amount D than the case of adding to the original first phase information is obtained. be able to. As a result, as shown in FIG. 5, the fluctuation period of the second phase information overlaps with the fluctuation period of the first phase information.

  In the example of FIG. 3, the correction amount Adj is obtained by correcting the first phase information after correction (two-dot chain line in FIG. 5) and the second phase information (FIG. 5) obtained by modulating the first phase information after correction. 5 as a difference). However, as can be seen from the comparison between FIG. 4 and FIG. 5, these graphs show the second phase obtained by modulating the first phase information output by the phase counter (solid line in FIG. 4) and the first phase information that is not corrected. The graph of the phase information (dotted line in FIG. 4) is translated by a shift amount D in the direction of increasing the time. Therefore, even in the method of FIG. 3, the correction amount Adj corresponding to the shift amount D can be obtained without being influenced by the correction (actually there is no particular problem because it passes through the LPF 210). it can.

  By performing the above correction, the fluctuation period of the second phase information input to the waveform information acquisition unit 204 can be kept constant regardless of the content of the processing performed by the modulation value calculation unit 205, so that the processing content is dynamic. Even when the output waveform data is generated based on the phase information that has been subjected to the modulation processing that changes to an unintended pitch change in the output waveform data can be suppressed.

Note that the processing corresponding to the function of the waveform generation unit 131 shown in FIG. 3 can be the one shown in the flowchart of FIG.
The CPU 11 starts the process of FIG. 6 for each sample period by executing a software synthesizer plug-in program. Note that if the waveform data can be prepared in time for output, the execution interval of the processing of FIG. 6 does not necessarily match the sampling period at the time of reproduction.

In the process of FIG. 6, the CPU 11 first adds the count value (first phase information) of the phase counter 201 based on the frequency information supplied from the pitch generator 122 (S11). At this time, the adjustment is made so that the count value falls within the range of 0 to 1, as described above.
Next, the CPU 11 adds the correction value Adj set in the previous process to the first phase information after the addition in step S11 (S12). Further, the modulation value Mod set in the previous process is added to the addition result to generate second phase information (S13). As described above, the adjustment is performed so that the count value falls within the range of 0 to 1 even in these steps.

  Next, the CPU 11 acquires a sample value of the waveform information corresponding to the second phase information by processing corresponding to the function of the waveform information acquisition unit 204 (S14), and outputs this to the volume control unit 132 (S15). . In addition, the sample value acquired in step S14 is input to a modulation value generation routine corresponding to the function of the modulation value calculation unit 205 (S16). Then, the CPU 11 sets the output of the modulation value generation routine in this sample period as the modulation value Mod (S17).

Further, the CPU 11 determines whether or not the second phase information has overflowed when adding the modulation value Mod in step S13 (S1 is subtracted because the addition result exceeds 1) (S18). If Yes here, the CPU 11 calculates the value of the first phase information + correction value Adj when the second phase information becomes 0 by interpolation, and sets it as the correction preparation value Adjp (S19). If No in step S18, step S19 is skipped.
In any case, the CPU 11 inputs the correction preparation value Adjp at this time to the LPF processing routine corresponding to the function of the LPF 210 (S20). Then, the CPU 11 sets the output of the LPF processing routine in this sample period as the correction value Adj (S21), and ends the processing.

Next, a modification of the above-described embodiment will be described. This modification is different from the above-described embodiment only in the configuration of the waveform generation unit 131.
FIG. 7 shows a functional configuration of the waveform generation unit 131 in the modification. In this figure, components corresponding to those shown in FIG. 3 are assigned the same reference numerals as in FIG.

  In the modification shown in FIG. 7, the difference calculation unit 207 adds the phase value output from the phase counter 201 (first phase information before correction), and the addition unit 211 adds the correction value Adj and the modulation value Mod. The difference from the later phase value (second phase information) is obtained. That is, a value obtained by inverting the sign of the total value of the correction value Adj and the modulation value Mod is obtained. The point of calculating the difference when the phase value of the second phase information becomes “0” is the same as in the case of FIG.

The addition unit 211 is a combination of the functions of the addition unit 202 and the addition unit 203 in FIG. 3, and adds the correction value Adj and the modulation value Mod to the phase value output from the phase counter 201 to obtain waveform information. Second phase information to be input to the acquisition unit 204 is generated. The order of addition may be either the correction value Adj or the modulation value Mod first.
In addition, when the addition unit 212 is provided and the switching unit 208 is connected, a value obtained by adding the difference detected by the difference calculation unit 207 to the correction preparation value Adjp currently held by the correction value holding unit 209 is obtained. Then, the new correction preparation value Adjp is supplied to the correction value holding unit 209 and held.
The functions of other units including the timing detection unit 206, the switching unit 208, and the LPF 210 are the same as those in the example of FIG.

  According to the waveform generation unit 131 described above, the correction value Adj can be adjusted based on the output of the phase counter 201 indicated by the solid line at the timing when the modulated phase information indicated by the dotted line in FIG. 5 changes from 1 to 0. . Therefore, if the phase information after modulation is different from the output of the phase counter 201 and the timing of changing from 1 to 0 is different, the value of the correction value Adj can be changed in a direction to cancel it. Therefore, as in the case of the configuration of FIG. 3, the post-modulation phase information and the “phase” of the output of the phase counter 201 can be matched.

Although the description of the embodiment is finished as described above, it goes without saying that the configuration of the apparatus and functions, the specific processing procedure, and the like are not limited to those described in the above-described embodiment.
For example, the timing at which the difference calculation unit 207 calculates the difference and supplies it to the correction value holding unit 209 is not the timing at which the second phase information or the first phase information overflows (based on the value at the end of the fluctuation region) The timing may be based on a value in the middle of the fluctuation region, such as when the phase value exceeds 0.5.

Further, the variation range of the phase value is not limited to 0 to 1. Furthermore, it is not essential that this fluctuation range corresponds to one period of the waveform. For example, the phase value variation range may correspond to a plurality of periods of the waveform, such that the phase value 0 corresponds to the phase 0 of the sine wave and the phase value 1 corresponds to the phase 4π of the sine wave. .
Further, the functions related to the generation and output of the waveform data shown in FIGS. 2 and 3 may be realized not by software but by dedicated hardware or a combination of software and hardware.

Further, the present invention can be applied to an arbitrary acoustic signal processing apparatus or a computer having a function other than the generation and output of waveform data by the functions shown in FIGS. 2 and 3, such as a multitrack recorder, an electronic musical instrument, and a sound source device. Of course, the present invention can be applied to a program for realizing the functions of such an acoustic signal processing device.
In this case, it goes without saying that the acoustic signal processing apparatus may include the sound system, display, etc. shown outside the waveform generating apparatus 10 in FIG.

  The program for realizing the functions of the above-described acoustic signal processing device or waveform generation device may be stored in a ROM or other nonvolatile storage medium (flash memory, EEPROM, etc.) provided in the computer from the beginning. Good. However, it can also be provided by being recorded on an arbitrary nonvolatile recording medium such as a memory card, CD, DVD, or Blu-ray disc. Each procedure described above can be executed by installing the program recorded in the recording medium in a computer and executing the program.

Furthermore, it is also possible to download from an external device that is connected to a network and includes a recording medium that records the program, or an external device that stores the program in a storage unit, and install and execute the program on a computer.
In addition, the configurations and modifications described above can be applied in appropriate combinations within a consistent range.

As is clear from the above description, even when output waveform data is generated based on phase information subjected to modulation processing whose processing contents dynamically change, an unintended pitch change in the output waveform data can be suppressed.
Therefore, the quality of the output waveform data can be improved by applying the present invention.

DESCRIPTION OF SYMBOLS 10 ... Waveform production | generation apparatus, 11 ... CPU, 12 ... ROM, 13 ... RAM, 14 ... HDD, 15 ... DMA control part, 16 ... DAC, 17 ... External apparatus I / F, 18 ... Display circuit, 19 ... Detection circuit, DESCRIPTION OF SYMBOLS 20 ... Communication I / F, 21 ... System bus, 101 ... MIDI driver, 102 ... Audio driver, 110 ... Sequencer application, 120 ... Software synthesizer plug-in, 121 ... Event handler, 122 ... Pitch generation part, 123 ... Envelope signal generation , 124 ... operator, 125 ... output unit, 131 ... waveform generation unit, 132 ... volume control unit, 201 ... phase counter, 202, 203, 211, 212 ... addition unit, 204 ... waveform information acquisition unit, 205 ... modulation value Calculation unit 206 ... Timing detection unit 207 ... Difference calculation unit 208 ... Switching unit 209 ... Correction value Sandwiching member, 210 ... LPF

Claims (5)

Computer
Waveform generating means for generating, as waveform information, a sample value corresponding to the phase information based on the input phase information;
Phase information generating means for generating first phase information based on the supplied frequency information;
Modulation means for modulating the first phase information using the waveform information generated by the waveform generation means;
Correction means for correcting the shift of the fluctuation cycle of the phase information caused by the modulation by the modulation means;
A program for causing the waveform generation means to function as input means for inputting second phase information obtained by adding modulation by the modulation means and correction by the correction means to the first phase information. The program according to claim 1,
The correction unit detects a difference in phase information before and after modulation as a shift amount of the fluctuation period when the phase information after modulation by the modulation unit becomes a predetermined value, and only the difference is detected by the modulation unit. A program for correcting phase information before modulation. The program according to claim 1,
The correction means detects a difference between the first phase information and the second phase information when the second phase information reaches a predetermined value, adjusts a correction amount of the phase information by the difference, and A program that corrects phase information by an amount after correction. A program according to any one of claims 1 to 3,
The said correction | amendment means is provided with a means to make the time change of the correction amount which concerns on the said correction slower than the time change of the detected deviation | shift amount of the said fluctuation | variation period. Waveform generating means for generating, as waveform information, a sample value corresponding to the phase information based on the input phase information;
Phase information generating means for generating first phase information based on the supplied frequency information;
Modulation means for modulating the first phase information using the waveform information generated by the waveform generation means;
Correction means for correcting the shift of the fluctuation cycle of the phase information caused by the modulation by the modulation means;
A waveform generation apparatus comprising: input means for inputting second phase information obtained by adding modulation by the modulation means and correction by the correction means to the first phase information.

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