JP3399272B2 - Music sound generating apparatus and music sound generating method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical tone generating apparatus and a musical tone generating method suitable for electronic musical instruments such as a digital synthesizer and other various electronic devices having a musical tone generating function (personal computer, game device, karaoke device, etc.). .

[0002]

2. Description of the Related Art Conventionally, a feedback F using a sawtooth wave (sawtooth wave) as a fundamental wave has been used as an analog synthesizer.
The M-modulation type waveform generator is provided on the master side and the slave side in total of two systems, and an oscillator of the slave side fundamental wave (frequency saw wave) at each cycle of the master side fundamental wave (frequency saw wave). Some have an oscillator synchronization function that resets the. In such an analog synthesizer, resetting of the slave oscillator is usually triggered by input of a pulse output from the master oscillator when the phase of the master fundamental wave becomes zero.

According to such an analog synthesizer, a tone signal of frequency fm is output from the waveform generating section on the master side, and a frequency fs is output from the waveform generating section on the slave side.
A tone signal having a spectrum component other than fs is output at a pitch interval corresponding to fm with a center frequency of. The master-side and slave-side tone signals thus generated are mixed in a subsequent stage to obtain a desired tone color.

[0004]

Due to the rapid progress of digital signal processing technology in recent years, various kinds of digital synthesizers have been developed, and due to factors such as their performance and high affinity with peripheral devices, today, It is much more widely used than analog synthesizers. Digital synthesizers have more diverse functions than analog synthesizers, and although they have gained overwhelming support in this respect, they do not have the same functions as analog synthesizers, such as the oscillator synchronization function described above. There is also a strong demand for equipment that can be imitated.

Here, the digitization of the oscillator synchronization function in the analog synthesizer will be considered. 12
Is a block diagram showing a schematic configuration of a digital synthesizer in a case where an oscillator synchronization function in an analog synthesizer is simply digitized based on its principle,
It is provided with two waveform generation units 1 and 2.

When data designating a tone color or the like is input to the digital synthesizer shown in FIG. 12 via a keyboard or various switches, the performance information generating section 3 and the tone color specifying information generating section 4 respectively perform the performance information. (KC, KON)
And tone color designation information (TC). This allows
From the frequency information generation means 5, a value corresponding to the frequency fm (master side fundamental wave frequency information) and a value corresponding to the frequency fs (slave side fundamental wave frequency information) are output for each sampling cycle.

In the configuration shown in FIG. 12, a modulo (mo) type adder 6 for truncating bits exceeding the effective bits in fixed-point arithmetic and an addition result by the adder 6 are stored and are added to the adder 6 at the next addition. The memory element 7 to be supplied constitutes a counter for counting the master side fundamental wave frequency information generated by the frequency information generating means 5, and functions as a master side oscillator (master OSC). However, it is assumed that the count value of each counter is represented by 2's complement, the initial value is 0, and the numerical range in which the valid bit can be expressed is -1 to 1. Similarly, the slave side fundamental wave frequency information generated by the frequency information generating means 5 is counted by the counter (slave OSC) including the adder 8 and the storage element 9.

As shown in FIG. 13, the master OSC counting result, that is, the transition of the master-side fundamental wave phase information "Pm" is returned from the upper limit "1" to the lower limit "-1" at a cycle corresponding to fm. , It becomes a sawtooth transition that increases linearly within each cycle. On the other hand, the count result of the slave OSC, that is, the transition of the slave-side fundamental wave phase information “Ps”, the reset control unit 10 resets the memory element 9 to 0 when the overflow of the adder 6 is detected. The transition is from the upper limit “1” to the lower limit “−1”, increasing linearly in each cycle, and being reset to 0 in each fm cycle. Then, the counting results of each counter are supplied to the waveform generating section 1 and the waveform generating section 2 as Pm and Ps, respectively.

By the way, the configuration shown in FIG. 12 has a problem in that, as shown in FIG. 13, a deviation (jitter) occurs in the reset timing of Ps, which adversely affects the obtained sound quality. This jitter is jitter that occurs when the overflow detection time of the adder 6 lags behind the time when the phase of Pm becomes 0. The actual detection time is after the time when the phase of Pm becomes 0. It will be the first sampling point. Therefore, a deviation occurs in the time position between the actual reset timing and the ideal reset point for each Pm cycle, and this deviation causes jitter on the slave side. The occurrence of the above-mentioned jitter cannot be completely prevented because it is composed of a digital circuit and the sampling frequency is not always an integral multiple of fm.

In the configuration shown in FIG. 12, the slave side fundamental wave frequency information and the slave side fundamental wave frequency information are cumulatively added for each sampling period. If the sampling frequency is an integral multiple of fm, the sampling point is also reached when the phase of Pm becomes 0, and jitter does not occur, but since fm is variable, the sampling frequency is set sufficiently higher than fm. Alternatively, it is necessary to change the sampling frequency to be an integral multiple of fm. In the former case, considering that fm is variable, the sampling frequency needs to be extremely high in order to obtain sufficient sound quality, and a huge amount of calculation is required.

In most digital audio equipment, the sampling frequency is fixed (for example, 44.1 kHz), and the digital circuit shown in FIG.
Since it is common to adopt a frequency commonly used in DSP,
It is also difficult to adopt the latter. In the first place, even if the latter is adopted, the amount of calculation becomes enormous when fm is high. The present invention has been made under such a background, and is capable of realizing an oscillator synchronization function, electronic musical instruments such as a digital synthesizer, and various electronic devices (personal computer, game device, karaoke) that also have a tone generation function. It is an object of the present invention to provide a musical tone generating device and a musical tone generating method suitable for a device).

[0012]

In order to solve the above-mentioned problems, the present invention is directed to accumulating master side fundamental frequency information.
And the accumulated value exceeds the upper limit,
The excess from the upper limit is set as the accumulated value, and the master side
A master side basic waveform generating section including a master side oscillator that outputs master side phase information that represents the accumulated value of the basic frequency information , and a master side waveform generating section that generates a signal according to the master side phase information, and a slave Side fundamental frequency information
When the accumulated value exceeds the upper limit while repeating the accumulation of
In that case, the excess from the upper limit is regarded as the cumulative value, and the
Slave-side basic waveform generation unit including a slave-side oscillator that outputs slave-side phase information that represents the accumulated value of the slave- side basic frequency information , and a slave-side waveform generation unit that generates a signal according to the slave-side phase information When it is detected that the master side phase information exceeds the upper limit value, an initial value of the slave side phase information is obtained based on the master side phase information at that time, and the initial value is set to the slave value.
An initial value setting means for setting the slave side oscillator as an accumulated value of the basic frequency information on the slave side is provided. In addition, the present invention, mass
It repeats the accumulation of the basic frequency information on the target side and accumulates it.
When the value exceeds the upper limit value, the excess from the upper limit value
The cumulative value of the master side fundamental frequency information is used as the cumulative value.
A master oscillator for outputting a master phase information indicating a master-side basic waveform generation section composed of a master waveform generator for generating a signal corresponding to the master-side phase information, the accumulation of the slave side fundamental frequency information With repeating
When the accumulated value reaches the upper limit value,
The excess is used as a cumulative value, and the slave side basic frequency information
A slave side oscillator that outputs slave side phase information indicating an accumulated value, and a slave side basic waveform generation section that includes a slave side waveform generation section that generates a signal according to the slave side phase information, and the master side phase information. Exceeds the above upper limit
When it is detected, the initial value of the slave-side phase information based on the master-side phase information at that time, the oscillation frequency of the master-side oscillator, and the oscillation frequency of the slave-side oscillator, and the initial value is calculated. The slave
There is provided a musical tone generating device comprising: an initial value setting means for setting the slave side oscillator as an accumulated value of the side fundamental frequency information . In addition, this invention is a master
-Side fundamental frequency information is repeatedly accumulated and the accumulated value
Reaches the upper limit, the excess from the upper limit is accumulated.
The accumulated value of the basic frequency information on the master side is displayed.
Master side oscillator that outputs master side phase information,
A master that generates a signal according to the master side phase information
A master-side basic waveform generating section consisting of a side-side waveform generating section,
While repeating the accumulation of basic frequency information on the slave side,
When the accumulated value exceeds the upper limit value, it exceeds the upper limit value.
Minutes are used as the accumulated value and the slave side fundamental frequency information is accumulated.
Oscillation on the slave side that outputs phase information on the slave side that indicates the value
And a stage for generating a signal according to the phase information on the slave side.
Basic waveform generation on slave side consisting of waveform generation section on rave side
And a musical tone generating method in a musical tone generating device including a section.
Therefore, if the phase information on the master side exceeds the upper limit value,
When and are detected, the master position at that time
The initial value of the slave side phase information is calculated based on the phase information.
Therefore, the initial value is set to the accumulated value of the basic frequency information on the slave side.
The slave side oscillator is set as
A method of generating a musical tone is provided.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention basically suppresses the influence of jitter by properly controlling the slave side fundamental wave phase information "Ps" at the time of reset, and further, the window to Ps near reset is displayed. P by multiplying (window)
By suppressing aliasing in the waveform of s, the oscillator synchronization function provided in the analog synthesizer is realized.

Now, the proper control of Ps at the time of reset, which is the basis of the present invention, will be described with reference to FIG. FIG. 2 is a graph showing the transition of the master-side fundamental wave phase information “Pm” and the ideal transition of Ps from FIG. 13 and sampling each sampling point in a time series when the sampling interval is extremely long. FIG. 13 is a diagram drawn in association with the time axis, and in this diagram, the sampling point t1 is the time when the reset process is actually performed in the circuit shown in FIG.

As shown in FIG. 2, the ideal Ps is
It already has a value different from 0 at the sampling point t1. Therefore, the basic control method of the present invention is to reduce the adverse effect of jitter on the sound quality by setting an ideal Ps at the sampling point t1 where the reset process is actually performed. The ideal Ps at the time of actual reset is basically estimated from the master side fundamental wave frequency information “fm” and Pm at the time of reset at the reset time when the sampling frequency is infinite, and the reset time and the slave It is obtained from the side fundamental wave frequency information “fs”.

The process of obtaining the ideal Ps at the time of actual reset will be specifically described below. However, in the following description, it is assumed that 0 <fm <1 and 0 <fs <1. In the two sawtooth waves, the ratio of the frequency and the ratio of the slope of the tooth portion of the wave are equal. In addition, in FIG.
Since the time when the Ps is reset to -1 and the time when Ps is reset to 0 coincide with each other, the ratio Ps / Pm ′ of the values in which Ps and Pm have increased by the same sampling point t1 is
It is equal to the ratio of the inclination of the tooth portion of the Ps wave to the inclination of the tooth portion of the Ps wave. Therefore, the expression (1) is established.

Ps / Pm ′ = fs / fm (1) Equation (2) is derived from Equation (1), and Pm ′ = Pm
Since it is +1, the formula (3) is obtained. Ps = Pm ′ / fm · fs (2) Ps = (Pm + 1) / fm · fs (3) That is, the ideal Ps at the time of actual reset is
Obtained by fm, fs, and Pm at the actual reset.

An embodiment of the present invention to which the above-mentioned basic method is applied will be described below with reference to the drawings. In each drawing, common portions are denoted by the same reference numerals, and overlapping description will be omitted. A. First Embodiment FIG. 1A is a block diagram showing the configuration of an electronic musical instrument according to the first embodiment of the present invention. The electronic musical instrument shown in this figure has two SAW (sine analog wave) waveform generators. ) Generators 11 (master side) and 12 (slave side) are provided. These SAW generators 11 and 12 have the same structure, and the feedback F as shown in FIG.
It is configured to realize waveform generation in the M method. The feedback FM method adopts a configuration in which sequential addresses (phase information) are input to the waveform memory and a part of the output from the waveform memory is fed back to the input stage of the waveform memory, and the amplification factor of the feedback signal is changed. In this method, the waveform of the output signal of the waveform memory is set to a desired waveform.

Specifically, as shown in FIG. 1B, x input as an address is a modulo type adder F.
It is input to the sine table FM1 via M7, and here, for example, the expression “y = −sin (π ·
x) ”is converted to y. This y is output as SAW, and the adder FM2 and the amplifier F with the amplification factor a are
It is supplied to the storage element FM5 via M3 and the adder FM4 and stored therein. The value stored in the memory element FM5 is output at the next sampling timing, and the amplifier F
After being amplified by M6, it is fed back to the modulo type adder FM7, and also input to the inverting input terminal of the adder FM2 and the non-inverting input terminal of the adder FM4. Each of the elements FM2 to FM6 is realized by, for example, an IIR (infinite length impulse response) filter.

The configuration of FIG. 1A will be described again. On the master side in FIG. 1A, 13 is a modulo (mo) type adder that cuts off bits exceeding valid bits in fixed-point arithmetic, and 14 is an adder for storing the addition result of the adder 13 at the next addition. The adder 13 and the storage element 14 are storage elements that are supplied to the counter 13, and form a counter (master OSC) that counts input values. That is, the master OSC has the master-side fundamental frequency information “fm” indicating the frequency of the master-side fundamental wave.
And supplies the master side fundamental wave phase information “Pm”, which is the counting result, to the SAW generator 11. However, the count value of each master OSC is represented by 2's complement, the initial value is 0, and the numerical range in which the effective bit can be expressed is -1 to -1.
It shall be 1.

Similarly, on the slave side, the modulo type adder 15 and the storage element 16 are the slave OS.
When C is configured and the switch 17 is switched to the 0 side, the slave side fundamental wave frequency information “fs” indicating the frequency of the slave side fundamental wave is counted, and the slave side fundamental wave which is the counting result is counted. The wave phase information “Ps” is supplied to the SAW generator 12.

Reference numeral 18 is a modulo type adder for adding a constant "1" to Pm and outputting Pm '. Reference numeral 19 is for dividing Pm' input from the x input end by fm input from the y input end to obtain a quotient p. A divider for outputting from the output end, 20 is a multiplier for multiplying fs by the output value from the p output end to calculate Ps at the time of resetting, and the output end is connected to the 1-side terminal of the switch 17. . That is, the adder 18, the divider 19, and the multiplier 20 are configured to realize the above expression (3).

Reference numeral 21 denotes a reset detector, which is an adder 13
Overflow is detected, the switch 17 is switched to the 1 side, and the switch 17 is switched to the 0 side at the next sampling point. The reset detector 21
For the reset detection by, the overflow of the master OSC may be directly detected.
Further, the overflow may be detected by detecting that the current Pm has decreased.

According to such a configuration, the master OSC
If no overflow has occurred in the master OS
The master side fundamental wave phase information indicating the sampling value of the sawtooth wave of the frequency fm is sequentially supplied from C to the SAW generator 11, and the slave side indicating the sampling value of the sawtooth wave of the frequency fs is supplied from the slave OSC to the SAW generator 12. The fundamental wave phase information is sequentially supplied.

On the other hand, when an overflow occurs in the master OSC, the reset detector 21 detects the overflow and switches the switch 17 to the 1 side. In parallel with this, P is obtained by the adder 18 adding 1 to Pm.
m ′ is output, the divider 19 divides the Pm ′ by fm, and the multiplier 20 multiplies the quotient of the division by fs and outputs Ps to the terminal on the 1 side.

As a result, Ps output from the multiplier 20
Is supplied to the SAW generator 12 and the storage element 16, and S
Slave SA according to ideal Ps from AW generator 12
W is output. In addition, Ps output from the multiplier 20
Is stored in the storage element 16 and supplied to the adder 15 at the next sampling timing (the switch 17 is switched to the 0 side at the next sampling timing). As a result, the subsequent slave SAWs have a waveform corresponding to the ideal Ps.

The format of waveform generation in the SAW generators 11 and 12 is y = sin (π · x), not y = sin (π · x).
-Sin (π · x) is the SAW generator 11, 1
2 is a feedback FM type waveform generator. Feedback of the slave side fundamental wave phase information (address) generated by the oscillator synchronization function described above.
When supplying to the M type waveform generator, the SAW generator 12
When the slave side fundamental wave phase information is reset when the slope of the output waveform from is positive, the SAW generator 12 forms a positive feedback loop, so even if the phase difference is extremely small, the output waveform jumps. This may cause unstable operation of the SAW generator 12, such as occurring or not occurring.

In the present embodiment, since the slave side fundamental wave phase information is reset near 0 (near the slope of the wave represented by y = sin (π · x) has a positive maximum value), y =
By setting −sin (π · x), the output waveform of the SAW generator 12 is reset near the maximum negative value. Of course, even if the waveform generation format of the sine table is set to y = sin (π · x) and the slave side fundamental wave phase information at the time of reset is set to Ps-1, the same result as above is obtained. Note that the slave-side fundamental wave phase information at the time of resetting tends to shift as the frequency of the slave-side fundamental wave increases, and therefore measures may be taken to correct this.

B. Second Embodiment FIG. 3 is a block diagram showing the configuration of an electronic musical instrument according to a second embodiment of the present invention. The electronic musical instrument shown in this figure is shown in FIG.
A major difference from the one shown in (a) is that division, which requires many operations, is eliminated.

In order to eliminate the division, in this embodiment,
When inputting the logarithm of the fundamental wave frequency information of the master side and slave side without directly inputting it and dividing by the number dividing the master side fundamental wave frequency information (reset), exponential conversion The reciprocal of the master side fundamental wave frequency information is obtained by the exponent table and the multiplication using this is performed.

The logarithm of the master side fundamental wave frequency information "fm" and the logarithm of the slave side fundamental wave frequency information "fs" are represented by Lm and Ls in FIG. 2, and the values of these Lm and Ls are -1. The bases of the logarithms are set independently on the master side and the slave side so that it becomes ~ 1. In the figure, 22,
Reference numeral 23 is an index table provided on the master side and the slave side. Inputting Lm and Ls respectively, fm and f
Output s. The fm and fs output from the index tables 22 and 23 are supplied to the adder 13 and the adder 15, respectively, as in the first embodiment.

Further, 24 is an overflow protection addition (ov) type adder for adding a constant "1" and -Lm input from the inverting input terminal, and 25 is a calculation result of the adder 24 and 1 / ( 256 · fm) is an exponential table, and the base of the logarithm is 1/256. Note that o
The v-type adder is an adder that limits the operation result to -1 to 1, and the operation result exceeding this range is limited to 1 or -1. Further, in the present embodiment, when the type (ov type / modulo type) of the adder is not particularly specified,
It is assumed to be an ov type adder.

26 is Pm 'output from the adder 18 and 1 / (256.fm) output from the exponent table 25.
A multiplier for multiplying and, 27 is a multiplier for left-shifting the multiplication result in the multiplier 26 by 8 bits (256) and outputting Pm ′ / fm, and 28 is a Pm ′ output from the multiplier 26.
This is a multiplier that multiplies / fm and fs output from the index table 23 and supplies the result to the 1-side terminal of the switch 17.
That is, the adder 18, the adder 24, the index table 2
5, the multiplier 26, the shifter 27, and the multiplier 28 are configured to obtain the ideal Ps at the time of resetting according to the above equation (2).

According to this structure, Lm is converted into fm by the exponent table 22, and the adder 13 and the storage element 14 are converted.
And Ls are converted into fs by the exponent table 23, and the adder 15 and the storage element 16 are supplied.
Is supplied to the slave OSC consisting of Since the operation after each OSC is the same as that of the first embodiment, the description is omitted.

On the other hand, when an overflow occurs in the master OSC, the reset detector 21 detects the overflow and switches the switch 17 to the 1 side. In parallel with this, the adder 24 adds −Lm to the constant “1”, and the exponent table 25 exponentially converts the addition result of the adder 24 and outputs 1 / (256 · fm). Further, the output (1 / (256 · fm)) of the exponent table 25 and the output (Pm ′) of the adder 18 are multiplied, and the multiplication result is shifted.
7 is left-shifted by 8 bits.

The output of the shifter 27 is multiplied by fs from the exponent table 23 in the multiplier 28 and supplied to the SAW generator 12 and the storage element 16 via the switch 17. As described above, the multiplication result of the multiplier 28 becomes the ideal Ps at the time of reset, and hence the subsequent operation is the same as that of the first embodiment. With such an operation, it is possible to obtain the same effect as that of the first embodiment, and it is also easy to configure by the DSP because the division which requires many operations is not used.

In this embodiment, the accurate reciprocal of fm (actually 1 / (256 · fm)) is obtained when fm is in the range of 1/256 to 1, and fm is If it is out of the range, an error occurs. However, since fm is sufficiently small (the frequency of the master side fundamental wave is sufficiently low), there is no problem in ignoring the jitter caused by the error. Further, in the present embodiment, the base of the logarithm in the exponent table 25 is set to 1/256 in order to secure the number of significant digits of the operation, but the exponent table 25 and the shifter 27 are not limited to this, and the exponent table 25 and the shifter 27 may have any desired values. You can easily change it just by changing it according to the bottom.

[Modification] FIG. 4 is a block diagram showing the structure of a modification of the electronic musical instrument according to the second embodiment.
The major difference between the modification shown in this figure and that shown in FIG. 3 is that the information on the frequency of the slave side fundamental wave is given by the ratio to the frequency of the master side fundamental wave.

In FIG. 4, fr and Lr respectively represent the ratio (fs / fm) of the frequency of the slave side fundamental wave to the frequency of the master side fundamental wave, and its logarithmic value. Lr is input to 25 to obtain fr / 256, and the output of the shifter 27 is directly supplied to the 1-side terminal of the switch 17. Further, 29 is fm output from the index table 22 and fr / 256 output from the index table 25.
The shifter 30 for multiplying by is a shifter for shifting the operation result of the multiplier 29 to the left by 8 bits (256),
The fs obtained as a result of the left shift is supplied to the adder 15.

With such a configuration, the operation on the master side is similar to that shown in FIG. On the slave side, Lr is converted to fr / 256 in the exponent table 25, converted to fs / 256 based on fm in the multiplier 29, and further converted to fs in the shifter 30 to be slave O.
Supplied to SC. Subsequent operations are the same as those shown in FIG. 3, so description thereof will be omitted.

On the other hand, when an overflow occurs in the master OSC, the reset detector 21 detects the overflow and switches the switch 17 to the 1 side. In parallel with this, in the multiplier 26, Pm ′ output from the adder 18 and fr / 256 output from the exponent table 25 are output.
Are multiplied by and the multiplication result (Pm ′ · fs / (256
.Fm)) is left-shifted by 8 bits by the exponent table 25 and supplied to the SAW generator 12 and the storage element 16 via the switch 17. The value output from the index table 25 is an ideal Ps at the time of reset (specifically, Pm0 ′ / fm · fs), and hence the subsequent operation is the first.
It is similar to the embodiment.

As is apparent from the above description, according to this modification, in addition to the effect of the one shown in FIG. 3, fs is generated based on fm.
It is possible to generate fs such that fm / fs is constant (fr) even if only fs is changed, that is, fs is set to fm.
There is an effect that it can be followed.

In this modification, the information about the frequency of the master side fundamental wave is given as a logarithm, but the information may be given linearly, and in this case also, there is an advantage that the divider is not required. There is. Therefore, for example, linear frequency information (fm) can be directly provided from a CPU (central processing unit) or the like, and the amount of calculation of a DSP or the like can be reduced.

[Points to be improved] By the way, even if the slave side fundamental wave phase information at the time of reset is proper, aliasing does not disappear to some extent. The reason for this is that, for example, in the wavetable system, overtones exceeding the band limitation range are generated due to discontinuity of the waveform at the time of reset, and in the feedback FM system, a feedback system (for example, IIR filter) is used. This is because the previous value remains, and the waveform immediately after the reset is disturbed by being reset when the negative feedback is performed in the feedback system.

Therefore, it is considered that aliasing can be improved by setting an appropriate initial value in the feedback system at the time of reset, but it is difficult to obtain the initial value depending on the frequency and the phase at reset by a simple calculation. . However, the aliasing should be suppressed because it may cause aliasing noise at reset. Hereinafter, embodiments (third to fifth embodiments) having a function of correcting the waveform disturbance of the slave SAW immediately after resetting without setting an appropriate initial value in the feedback system at the time of resetting will be described.

C. Third Embodiment FIG. 5 is a block diagram showing the configuration of an electronic musical instrument according to a third embodiment of the present invention. The electronic musical instrument shown in this figure is shown in FIG.
The difference from that shown in (a) is that a window is created based on Pm, and the slave S
This is the point where the portion of the AW waveform corresponding to the reset time is shaped.

In FIG. 5, 31 is an absolute value generation circuit for outputting the absolute value of Pm output from the adder 13, 32 is the constant "1" when the output value from the absolute value generation circuit 31 is input to the inverting input terminal. Is added, 33 is a multiplier that multiplies the addition result of the adder 32 by a predetermined window width "wr", and 34 is a left-shift of the multiplication result of the multiplier 33 by a predetermined bit, and the upper limit value (here Then, a shifter limiter that limits by "1"), 35 is a window table that corrects the output value of the shifter limiter 34 and smoothes the boundary of the window represented by the series of the output value. On the other hand, the output value y is calculated by the following equation (4). y = (1-cos (π · x)) / 2 (4) Further, 36 multiplies the output value from the window table 35 and the output value from the SAW generator 12 to obtain the final slave SAW. Output.

With such a configuration, as in the case shown in FIG. 1A, the circuit related to the oscillator synchronization is connected to Pm.
(See * 1 in FIG. 6) and Ps are output. The absolute value of Pm is obtained by the absolute value generation circuit 31 (see FIG. 6 * 2), and is subtracted from the constant “1” in the adder 32 (see FIG. 6 * 3). Then, the multiplier 33 multiplies the subtraction result by a predetermined window width "wr" (see FIG. 6).
6) and the shifter / limiter 34 to obtain the waveform shown in FIG. 6 * 5. Note that normally, wr ≦ 1. The output waveform from the shifter / limiter 34 is shaped into a smooth waveform in the window table 35 (see FIG. 6 * 6) and supplied to the multiplier 36.

On the other hand, the waveform as shown by * 7 in FIG. 6 is supplied from the SAW generator 12 to the multiplier 36.
The waveform is disturbed near the reset time. Multiplier 3
In 6, the output value from the SAW generator 12 is multiplied by the output value from the window table 35 and output as the final slave SAW (see FIG. 6 * 8). In this way, a portion of the waveform of the slave SAW corresponding to the reset time is suppressed to "0", and a slave SAW having a waveform as shown by * 8 in FIG. 6 in which aliasing is sufficiently suppressed is obtained.

As described above, according to this embodiment, aliasing can be sufficiently suppressed by a relatively simple calculation. The window width "wr" can be set arbitrarily, but when wr is large, a sharp sound close to analog, wr
When is small, the sound is smooth and soft, so it is necessary to appropriately set it so that a desired sound can be obtained. Especially wr
In the case of a large value, if the master frequency is high, aliasing cannot be suppressed enough, which may cause aliasing noise. Therefore, the above setting should be made with this in mind.

D. Fourth Embodiment FIG. 7 is a block diagram showing the arrangement of an electronic musical instrument according to the fourth embodiment of the present invention. The electronic musical instrument shown in this drawing has two components.
Cross-fade that uses two slave OSCs to fade in the slave OSC on the reset side and fade out the slave OSC on the non-reset side.
It is intended to suppress aliasing by performing them alternately.

In FIG. 7, the constituent elements 13 to
Since the circuit formed of 21 (referred to as a fade-out side circuit for convenience) and the SAW generator 11 have the same configuration as the circuit shown in FIG. 1A, description thereof will be omitted. On the other hand, the components 12, 15 to 21, 37 to 40 on the right side of the drawing
Circuit consisting of (for convenience, called the fade-in circuit)
Inputs the same fs as the circuit on the fade-out side, and the divider 19 and the reset detector 21 and thereafter are shown in FIG.
It has the same configuration as the circuit shown in FIG.

In the fade-in circuit on the right side of the figure,
The adder 38 is a mo type adder, and the non-protect (np) type adder 37 is in the process of adding a constant “−1” to the pulse width “PW1” indicating the duty ratio of the window used in the subsequent stage. Without protecting the value of
Hold between two. The adder 38 adds Pm output from the master OSC and the addition result of the adder 37.
The storage element 39 holds the addition result of the adder 38 until the next sampling point. The adder 40 is the adder 3
8 and the storage element 39 input to the inverting input terminal
And the value from are added.

In the circuit on the fade-in side, the adder 18 is provided so as to input the addition result of the adder 38, and the reset detector 21 is a positive value of the value input from the adder 38 to the adder 40. The switch 17 is provided so as to switch the switch 17 by detecting the turning back from the negative side to the negative side. In addition, in the adder 40, when the value input from the adder 38 is folded back from the positive side to the negative side, the value supplied from the adder 38 is negative, and an overflow occurs in the adder 40. It is realized by detecting.

In the center and the lower side of the figure, a circuit for generating a window for crossfading and realizing the crossfading using the window is shown.
In this circuit, 41a is a multiplier for multiplying Pm output from the master OSC by a preset window width "wr", and 42a is a multiplication result of the multiplier 41a.
An ov type adder 43a for adding r is a shifter / limiter having the same function as the shifter / limiter 34 (see FIG. 5), and the addition result of the adder 42a is left-shifted by a predetermined bit and then a predetermined value is added. (Here, "1") to set the limit. Further, 44 is an ov type adder, and the adder 37
The intermediate result in the above step and Pm are added and supplied to the multiplier 41b. The multiplier 41b, the ov-type adder 42b, and the shifter / limiter 43b differ from the multiplier 41a, the adder 42a, and the shifter / limiter 43a only in that the processing target is not Pm but the addition result of the adder 44.

The adder 45 is provided so as to add the output from the shifter / limiter 43a and the output from the shifter / limiter 43b input from the inverting input terminal and supply the result to the window table 35.
Is configured to be supplied to the multipliers 46a and 46b. The multipliers 46a and 46b multiply the output of the window table 35 by the output from the SAW generator 12 of the fade-out side circuit and the output from the SAW generator 12 of the fade-in side circuit, respectively.

The ov type adder 4 is provided after the multiplier 46b.
7 is provided so that the multiplication result of the multiplier 46b is input to the inverting input terminal of the adder 47, and the output of the SAW generator 12 of the fade-in side circuit is input to the non-inverting input terminal. There is. That is, the waveform on the fade-out side in the window created from the multiplier 46a is added by the adder 4
7 is configured to output the waveform on the fade-in side outside the window. In addition, the mixer 48
The output of the multiplier 46a and the output of the adder 47 are mixed to generate a final slave SAW.

In this configuration, when fm and fs are input and PW1 and wr are input or set, Pm is output from the master OSC including the adder 13 and the storage element 14 (see * 1 in FIG. 8). ), This Pm is SAW
It is supplied to the generator 11, the adder 38, the multiplier 41 a, and the adder 44. Further, in the adder 37, PW1 (that is, −PW1) input from the inverting input terminal and −1 are added and supplied to the adder 38 and the adder 44.

In the adder 38, the output value of the adder 37 is added to Pm, and the phase of the wave represented by Pm is delayed by X (see FIG. 8 * 2). In this embodiment, X = π · (1 + P
W1), and the phase of the wave represented by Pm is delayed by 1.5π (that is, 75%) if PW1 is 0.5,
If it is −0.5, it is delayed by 0.5π (that is, 25%). In addition, here, in accordance with FIG. 10 and FIG.
The description will proceed assuming that 1 <PW1 <0.

The output of the adder 38 is input to the x input terminal of the divider 19 of the fade-in side circuit, divided by Pm input to the y input terminal thereof, and then multiplied by fs in the multiplier 20. . That is, at the sampling point where the output of the adder 38 turns from positive to negative, the ideal Ps at that time point is obtained and supplied to the 1-side terminal of the switch 17. Further, the reset detector 21 detects a sampling point at which the output of the adder 38 turns from positive to negative, and switches the switch 17 to the 1 side from that time point to the next sampling point.

Therefore, the SAW of the fade-in side circuit
As shown by * 11 in FIG. 8, the output from the generator 12 is delayed by (PW1 + 1) / 2 [%] of the cycle “T” of the wave from the time when the turn-back of the wave represented by Pm is detected. The waveform will be reset. On the other hand, the output from the SAW generator 12 of the fade-out side circuit is the same as in the first embodiment.
As shown by * 10 in FIG. 8, the waveform becomes a reset waveform at the time when the turn-back of the wave represented by Pm is detected.

The Ps supplied from the master OSC to the multiplier 41b is multiplied by wr here, and the adder 42 is added.
wr is added in a (where 0 <wr). As a result, as shown by * 4 in FIG. 8, a waveform in which all values (amplitude values) are 0 or more and 2 wr or less is obtained. The output of the adder 42a is supplied to the shifter / limiter 43a, where it is left-shifted by a predetermined number of bits and then has an upper limit value of "1".
Is limited by (See Fig. 8 * 5).

In addition, in the adder 44, the master OS
The output value of the adder 37 is added to Pm from C, and the addition result is supplied to the multiplier 41b. That is, the waveform as shown by * 3 in FIG. 8 is supplied to the multiplier 41b. The multiplier 41b, the adder 42b, and the shifter / limiter 43b, with respect to the output from the adder 44,
Multiplier 41a, adder 42b, shifter / limiter 43b
In order to perform the same processing as the above, the adder 42b and the shifter
The waveform represented by the output value from the limiter 43b is a waveform like * 6 and * 7 in FIG.

Next, in the adder 45, the output of the shifter / limiter 43a and the inverted value of the output of the shifter / limiter 43b are added. That is, the waveform shown in * 7 is subtracted from the waveform shown in * 5 to obtain the waveform shown in * 8. The output of the adder 45 is input to the window table 35, and the window table 35
From the multiplier 46a is a value representing a window with a smooth contour.
And to the multiplier 46b (see FIG. 8 * 9).

The multiplier 46a multiplies the output signal of the SAW generator 12 of the fade-out side circuit (see FIG. 8 * 10) by the output value of the window table 35. As a result, the output signal from the multiplier 46a has a waveform in which only the portion within the window remains, as shown by * 12 in FIG. On the other hand, in the multiplier 46b, S of the fade-in side circuit is
The output signal of the AW generator 12 (see FIG. 8 * 11) is multiplied by the output value of the window table 35. Multiplier 46
The multiplication result in b is input to the inverting input terminal of the adder 47,
Here, the output signals of the SAW generator 12 of the fade-in side circuit are added. That is, only the part that did not fit in the window as shown in * 9 of Fig. 8 remains (Fig. 8 *
13).

The output signal from the multiplier 46a and the adder 4
The output signal from 7 is mixed in the mixer 48 and output as the final slave SAW. After that,
Since the fade-in side circuit and the fade-out side circuit alternate their roles and alternately perform crossfades, a smooth slave SAW without aliasing can be obtained.

In the mixer 48, for example, the multiplier 4
The output signal of the multiplier 46b is subtracted from the output signal of 6a (see FIG. 8 * 14a), the output signal of the multiplier 46a and the output signal of the multiplier 46b are added (see FIG. 8 * 14b), etc. Any mixing process can be performed. Of course, various existing mixing methods such as changing the mixing ratio can be applied.

Further, when the window width "wr" is made large, the waveform represented by the output value from the adder 45 is a waveform which sharply rises and falls as shown by * 4 'in FIG. . In this case, the slave SAW output from the mixer 48 has a waveform capable of expressing small fluctuations near the crossfade time, as indicated by * 14 'in FIG. On the contrary, it is possible to make wr small, and various slave SAWs can be obtained.

Furthermore, the duty ratio of the window waveform can be changed by changing the pulse width "PW1". From the above, it is understood that according to the present embodiment, various waveforms that cannot be obtained by the conventional analog synthesizer can be obtained.

E. Fifth Embodiment By the way, when a feedback FM type waveform generator is used, basically only a sawtooth wave is obtained. However, in the analog synthesizer, a synchronized pulse or PWM wave can be easily obtained only by passing the synchronized sawtooth wave through the comparator (see FIG. 14). Moreover, the duty ratio of the output pulse can be easily changed only by changing the threshold values (th1, th2 in FIG. 14). In view of this, a fifth embodiment capable of obtaining a synchronized pulse or PWM wave using the present invention will be described below.

FIG. 10 is a block diagram showing the arrangement of an electronic musical instrument according to the fifth embodiment of the present invention. The electronic musical instrument shown in this figure is basically an S-type feedback FM system.
By using two AW generators, both SAW generators output signals of the same cycle with a phase shift, and by adding these signals, a pseudo-synchronized pulse or PWM wave is obtained.

In FIG. 10, the structure for obtaining the master SAW and the slave SAW (upper side in the drawing) is the same as the structure shown in FIG. 5, and therefore its explanation is omitted.
In the pulse signal generators GM and GS provided for obtaining the pulses, the same parts as those in FIG. 5 are designated by the same reference numerals and the description thereof will be omitted.

In the pulse signal generator GM, 49 is a multiplier for multiplying fm by the pulse width "PW2" input from the outside. PW2 is a value corresponding to the duty ratio of the pulse finally obtained, and for example, when the duty ratio of the slave pulse generated by using the SAW generator on the slave side is set to 0, 50, 100%. Is 0,
It is set as 0.5, 1. In the present embodiment, 0 ≦ PW2 ≦ 1, and PW2 and the duty ratio are in a proportional relationship.

The pulse signal generator GM is composed of the divider 1
The multiplication result of the multiplier 49 is applied to the x input terminal of 9 and f is applied to the y input terminal.
s is input. 50 is a divider 19
Is a shifter for doubling the output from the p output terminal, and 51 is a mo type adder for adding the output of the divider 19 input to the inverting input terminal and Pm, and outputs the addition result. At this time, P
The phase shift rate of the wave represented by the calculation result in the adder 51 with respect to the wave represented by m is inversely proportional to fs / fm, and PW
The shift rate is proportional to 2.

On the other hand, in the pulse signal generator GS,
The storage element 52, the mo type adder 53, and the reset detector 21 have the same output values as the storage element 39, the adder 40, and the reset detector 21 in the fade-in circuit in FIG. The switch 17 is provided so as to switch the switch 17 to the 1 side by detecting the sampling point that is turned from positive to negative. In addition, the pulse signal generator G
S is the adder 5 in the adder 18 and the absolute value generation circuit 31.
The output from 1 is supplied, and fs is input to the y input terminal of the divider 19.

Reference numerals 56 and 57 denote amplifiers, which are the slave SAW and the SAW of the pulse signal generator GS, respectively.
The output signal from the generator 12 is converted into a predetermined amplification factor (in order, 0.
5, -0.5). An adder 59 is provided after the amplifiers 56 and 57, adds the output signals of the amplifiers 56 and 57, and outputs as a slave pulse.

In such a configuration, fm, fs, P
When W2 is input and wr is input or preset, master SAW and slave SAW (* in FIG. 11)
1 * 3), the pulse signal generator GM multiplies fm by PW2 in the multiplier 49, and the multiplication result is input to the x input terminal of the divider 19.
Since fs is input to the y input terminal of the divider 19,
The divider 19 outputs fm · PW2 / fs, which is left-shifted by 1 bit in the shifter 50 to obtain PH (that is, 2 · fm · PW2 / fs). It should be noted that the shifter 50 multiplies 2 (shifts left by 1 bit).
Of PW2 has a fluctuation range of 0 to 1, while Ps
This is because the variation range of -1 is -1 to 1 and the output of the divider 19 needs to be doubled in order to make the scales of both the same in the addition by the adder 51 in the subsequent stage.

The output from the shifter 50 is input to the inverting input terminal of the adder 51 and added with Ps. This allows
A value representing the waveform as shown in * 2 of FIG. 11 is obtained,
This value is output. In * 2 of FIG. 11, X is the pulse width of the slave pulse finally obtained, and the fact that the phase shifts by X in this way means that PW2 is the slave SA.
It is clear that it is given as the ratio of X to the period "Ts" of W.

On the other hand, in the pulse signal generator GS, the value obtained by the adder 51 of the pulse signal generator GM (see FIG. 11).
(See * 2), P obtained from fs while monotonically increasing
Based on s, the SAW generator 12 in the pulse signal generator GS outputs a signal that matches the slave SAW. In addition, the pulse signal generator GS detects a sampling point at which the value obtained by the adder 51 of the pulse signal generator GM returns from positive to negative, finds an ideal Ps at the sampling point, and determines this. The signal is supplied to the SAW generator 12 and the storage element 16 in the pulse signal generator GS. These operations and the waveform shaping operation by the components 31 to 36 in the pulse signal generator GS are the same as the operations in the circuit of FIG. 5 except for the reset timing, and thus detailed description thereof will be omitted. From the multiplier 36 of the use signal generator GS to the amplifier 57, * 4 in FIG.
A signal having a waveform as shown in is supplied.

Therefore, the amplifier 56 multiplies the slave SAW by 0.5, the amplifier 57 multiplies the output signal from the multiplier 36 in the pulse signal generator GS by -0.5, and the adder 59 outputs both signals. Is added, the duty ratio becomes X / T
A pulse (slave pulse) of s, that is, 100 · PW2 [%] is output from the adder 59 (see FIG. 11 * 5).

As described above, according to this embodiment, a pulse having an arbitrary duty ratio can be generated. The pulse thus generated may be used as it is as an acoustic signal or may be used for signal processing such as FM modulation. Further, by setting PW2 in proportion to the duty ratio in the range of 0 to 1, it is possible to directly specify the duty ratio in the output signal. That is, it is possible to provide an interface that is easy for humans to understand.

In each of the above-described embodiments, an example using a feedback FM type waveform generator is shown, but a method using a wavetable type waveform generator or switching the band-limited waveform for each pitch is also applicable. Various other modes, such as adoption, are possible. Further, PW1 in the fourth embodiment and PW2 in the fifth embodiment are not limited to fixed values, and may be values modulated by LFO, EG, or a combination thereof. of course,
It is needless to say that each parameter does not have to be -1 to 1 or 0-1 and that parameters of any system and range can be adopted according to the circuit configuration. Further, in the above-described embodiment, an example in which the present invention is applied to an electronic musical instrument is shown, but the present invention is not limited to this,
It can be applied to various electronic devices (personal computers, game devices, karaoke devices, etc.) that also have a musical sound generation function.

[0089]

As described above, according to the present invention,
Master side basic waveform generator and slave side basic waveform generator
It is possible to reliably synchronize the oscillators of the raw parts .
Therefore, the output signals from the waveform generators are accurately synchronized.

[Brief description of drawings]

1A is a block diagram showing a configuration of an electronic musical instrument according to a first embodiment of the present invention, and FIG. 1B is a block diagram showing a configuration of a SAW generation unit included in the electronic musical instrument.

FIG. 2 is a diagram showing an ideal transition of each information in association with a sampling time axis in which a sampling interval is set to be extremely long.

FIG. 3 is a block diagram showing a configuration of an electronic musical instrument according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a modified example of the electronic musical instrument.

FIG. 5 is a block diagram showing a configuration of an electronic musical instrument according to a third embodiment of the present invention.

FIG. 6 is a diagram showing waveforms obtained in each unit of the electronic musical instrument.

FIG. 7 is a block diagram showing a configuration of an electronic musical instrument according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing waveforms obtained in each unit of the electronic musical instrument.

FIG. 9 is a diagram showing a waveform obtained when the electronic musical instrument has a large wr.

FIG. 10 is a block diagram showing a configuration of an electronic musical instrument according to a fifth embodiment of the present invention.

FIG. 11 is a diagram showing waveforms obtained at various parts of the electronic musical instrument.

FIG. 12 is a block diagram showing a schematic configuration of an electronic musical instrument in which an oscillator synchronizing function in an analog synthesizer is simply made into a digital circuit based on its principle.

FIG. 13 is a diagram for explaining the reason for the occurrence of jitter in the electronic musical instrument.

FIG. 14 is a diagram for explaining a method of obtaining synchronized pulses in an analog synthesizer.

[Explanation of symbols]

11 ... SAW generator, 12 ... SAW generator, 13 ... Adder, 14 ... Storage element, 15 ... Adder, 16 ... Storage element,
17 ... Switch, 18 ... Adder, 19 ... Divider, 20 ...
Multiplier, 21 ... Reset detector.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G10H ^7/ 00-7/12

Claims (8)

(57) [Claims] 1. The master side fundamental frequency information is accumulated.
When returning, when the accumulated value exceeds the upper limit,
The excess from the limit value is used as the cumulative value
A master side basic waveform generating section including a master side oscillator that outputs master side phase information that represents the accumulated value of wave number information , and a master side waveform generating section that generates a signal according to the master side phase information, and a slave side While repeating the accumulation of basic frequency information,
When the accumulated value exceeds the upper limit value, it exceeds the upper limit value.
Minutes are used as the accumulated value and the slave side fundamental frequency information is accumulated.
A slave oscillator for outputting a slave phase information representing the value, the slave and the slave-side basic waveform generator comprising a slave waveform generator for generating a signal corresponding to the phase information, the master-side phase information the Check that the upper limit has been exceeded
When issued, obtains the initial value of the slave phase information based on the master-side phase information at that time, the <br/> the slave oscillator initial value as the accumulated value of the slave side fundamental frequency information A musical tone generating apparatus, comprising: an initial value setting means for setting. 2. The master side fundamental frequency information is accumulated.
When returning, when the accumulated value exceeds the upper limit,
The excess from the limit value is used as the cumulative value
A master side basic waveform generating section including a master side oscillator that outputs master side phase information that represents the accumulated value of wave number information , and a master side waveform generating section that generates a signal according to the master side phase information, and a slave side While repeating the accumulation of basic frequency information,
Exceeding the upper limit when the accumulated value reaches the upper limit
Minutes are used as the accumulated value and the slave side fundamental frequency information is accumulated.
A slave-side oscillator that outputs slave-side phase information that represents a value, and a slave-side basic waveform generator that includes a slave-side waveform generator that generates a signal according to the slave-side phase information, and the master-side phase information is Check that the upper limit has been exceeded
When output, the initial value of the slave side phase information is obtained based on the master side phase information, the oscillation frequency of the master side oscillator, and the oscillation frequency of the slave side oscillator at that time, and the initial value is set to the slave side. Fundamental frequency
An initial value setting means for setting the slave side oscillator as an accumulated value of number information, the musical tone generating apparatus. 3. The method according to claim 1, wherein the fluctuation of the instantaneous value of the signal output from the slave side waveform generator is suppressed near the time when the initial value of the slave side phase information is set. The musical tone generator described. 4. Based on the master side phase information, the value of a portion corresponding to the vicinity when setting the initial value of the slave phase information to generate a small window information than the value of the other portions,
3. The musical tone generating apparatus according to claim 1, wherein the window information is applied to a signal output from the slave side waveform generating section. 5. The slave side basic waveform generating section has two systems, and the slave side basic waveform generation of the two systems.
With a mixer that mixes the output signals of the
However, the master side basic waveform generating unit is the master side frequency
The ratio of the information to the frequency information on the slave side,
Proportional to the product of the duty ratio of the pulse to be obtained from the mixer
The two master positions that are out of phase with each other by the phase difference
The phase information is output, and the initial value setting means outputs the phase information on the master side of the two systems.
When it is detected that one of the reports has passed the upper limit
One of the two slave side basic waveform generators
Set the initial value for the slave side oscillator of
The other side of the phase information on the master side of the two systems is the upper limit.
When it is detected that the value has passed,
From the slave side of the other one of the basic waveform generators on the slave side
An initial value is set for a shaker, and the mixer is a slave-side basic waveform generator of the two systems.
The initial value is set for each slave oscillator of
The signal output from each slave oscillator
It is characterized in that it cross-fades and outputs the pulse.
The musical sound generating device according to claim 1 or 2. 6. A logarithm of the master side fundamental frequency information
And exponential conversion to produce the master side fundamental frequency information
Logarithm of the index table and the basic frequency information on the slave side
To generate the slave side fundamental frequency information
And an index table for setting the master side fundamental frequency information.
And the logarithm of the slave side fundamental frequency information are used.
Calculate the initial value of the slave side phase information
Musical tone generating apparatus according to claim 2, wherein the that. 7. A slave of the slave side basic waveform generating section.
Slope of the change over time in the signal value of the output signal from the waveform generator
Is negative, the slave side basic waveform generator
Initialization of the slave side phase information for the Rabe side oscillator
Claims, characterized in that the value was configured to be set
The musical sound generating device described in 1 or 2. 8. The accumulation of basic frequency information on the master side is repeated.
When it returns, when the accumulated value reaches the upper limit,
The excess from the limit value is used as the cumulative value
Outputs phase information on the master side that indicates the cumulative value of wave number information
Master side oscillator and signal corresponding to the master side phase information
Master consisting of a master side waveform generator that generates a signal
Side basic waveform generator and repeat the accumulation of slave side basic frequency information,
When the accumulated value exceeds the upper limit value, it exceeds the upper limit value.
Minutes are used as the accumulated value and the slave side fundamental frequency information is accumulated.
Oscillation on the slave side that outputs phase information on the slave side that indicates the value
And a stage for generating a signal according to the phase information on the slave side.
Basic waveform generation on slave side consisting of waveform generation section on rave side
And a musical tone generating method in a musical tone generating device including a section.
It, validates that the master phase information exceeds the upper limit value
When issued, the master side phase information at that time
The initial value of the slave side phase information based on
The initial value as the accumulated value of the basic frequency information on the slave side
Musical sound characterized by setting to the slave side oscillator
Method of occurrence.