JPS63261390A - Input controller for electronic musical instrument - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an input control device for an electronic musical instrument such as an electronic guitar, and is intended to prevent malfunctions such as re-sounding even when no tremolo performance is performed. It has something to do with things.

[Background of the Invention] Conventionally, the pitch (fundamental frequency) is extracted from a waveform signal generated by the performance operation of a natural musical instrument, and a sound source device composed of an electronic circuit is controlled to artificially generate a sound 1 such as a musical tone. Various devices have been developed to achieve this goal.

In this type of electronic musical instrument, it is common to extract the pitch of an input waveform signal and then instruct the sound source device to generate a scale tone corresponding to the pitch.

The present application has been filed in order to enable re-sounding when a picking operation is performed on such an electronic musical instrument when a performance operation such as a tremolo technique is performed, that is, when a musical tone is produced by string vibration, and when a picking operation is performed. If a person detects that the level of the input waveform signal has suddenly increased while a musical tone is being generated, the user issues a command to start generating the tone again and turns on the relative signal (r
An application was filed (Japanese Patent Application No. 61-285985) that was able to follow the actual performance operations by performing ``elative on'' processing and changing the volume, tone color, etc.

However, each part of the waveform of the input waveform signal gradually changes as the sound emission time passes, and in particular, as shown in FIG. In the case of an input waveform signal with many overtone components, the peak of α gradually becomes smaller, but when the peak of β gradually increases, the level value of the peak of α and the level of the peak of β become smaller. The level value of the waveform increases near an-4 to an+5, where 1 is reversed, even though no tremolo operation is being performed.

There has been a problem in that relative-on (re-sounding) processing is performed and a new musical tone is emitted.

This phenomenon occurred more frequently as the number of peaks and valleys that existed in one cycle of the input waveform signal increased.

[Purpose of the Invention] This invention has been made in view of Article 2 th, and it is possible to perform a tremolo performance when an input waveform signal with many overtone components gradually changes as the sound emission time passes. Another object of the present invention is to provide an input device for an electronic musical instrument that can prevent malfunctions that result in re-sounding and can more reliably process musical tones.

[Summary of the Invention] In order to achieve this object, the present invention provides that, as shown in Section 711(d), the level of each portion indicated by α and β within one period of an input waveform signal is We focused on the fact that when the waveform gradually changes and reverses, the pitch data extracted as one cycle of the waveform suddenly becomes smaller. The key point is that the disclosure instructions are not given.

[Embodiment] Hereinafter, an embodiment in which the present invention is applied to an electronic guitar will be described in detail with reference to the drawings.

In this embodiment, as described below, the A/D converter 11, latch 12, OR gate 13, flip-flop 14.15, maximum peak detection circuit 4, and minimum peak detection circuit 5 serve as the detection means, and steps S35.58 to S35. The CPU 100, which executes
In step S3, the CPU 100 executing Step 1 serves as a measuring means, and the 0LDP register of the work memory 101 serves as a storage means.
The CPU 100 that executes step 4 corresponds to a determining means and an instruction inhibiting means, respectively.

Overall circuit configuration Figure 1 shows the overall circuit configuration of the same embodiment. Signals from the six input terminals l are connected to the strings connected to each of the six strings strung on the electronic guitar body. This is a signal from a pickup that converts vibrations into electrical signals.

Musical tone signals from the input terminals l... are sent to the respective amplifiers 2...
It is amplified by... and low pass filter (LPF) 3...
The high frequency component is cut and the basic waveform is extracted, and the maximum peak detection circuit (MAX) 4..., the minimum peak detection circuit (MIN) 5... and zero cross point detection are performed. It is given to the circuit (Zero) 6... The cutoff frequency of the low-pass filter 3 is set to 4f, which is four times the vibration sound frequency f of the open string of each string. This is based on the fact that the frequency of the output sound of each string is within two octaves. The maximum peak detection circuit 4 detects the maximum peak point of the musical tone signal, and at the rising edge of the detected pulse signal, the Q output of the flip-flop 14 connected to the subsequent stage becomes High. level, this flip-flop 14.
Output of... and zero cross point detection circuit 6...
The AND output with the inverted output of the inverter 30... is sent to the CPU as an interrupt command signal I N Tag to I N Ta6 via the AND gate 24...
100, and similarly the minimum peak detection circuit 5...
. . . However, when the minimum peak point of the musical tone signal is detected, the Q output of the flip-flop 15 connected to the subsequent stage becomes High level at the rising edge of the detection pulse signal, and this flip-flop 15 . The AND output of the output of . . . and the output of the zero cross point detection circuit 6 .
given to.

That is, the maximum peak point is detected and the flip-flop 14
When the waveform crosses from positive to negative while is at High level, the interrupt command signal I N Tag~r
N Tab is given to the CPU 100, and when the minimum peak point is detected and the flip-flop 15 is at a high level, when the waveform changes from negative to positive, interrupt command signals lNTb+ to lNTb6 are input to the CPU 100. .

Immediately after receiving these interrupt command signals, the CPU 100 executes the corresponding free 2 flop 14...
Clear signal CLa+ for ..., 15...
~CLab, CLb+ ~CLb6 is generated and reset. Therefore, no matter how many times the zero cross point is passed until the next maximum peak point or minimum peak point is detected, the corresponding flip-flops 14..., 15...
... is in a reset state, so no interrupt is applied to the CPU 100.

Then, in the CPU 100, an interrupt command signal 1NTa+ to lNTa6 or lNT is generated based on the vibration output of the string.
b+ to lNTb6 are given, and a scale tone according to at least one of the respective time intervals is generated. Sho 1
At the start of sound generation, the generation of open string scale tones may be started, and the frequency may be corrected after pitch extraction.The operation at the start of sound generation will be described later.

The above-mentioned time interval is determined using a counter 7 and a work memory lot, as will be described later. That is, the work memory 101 stores various data such as the count value of the counter 7 at the zero cross point immediately after the maximum peak point or immediately after the minimum peak point.

After the sound generation starts, the frequency of the musical tone being generated is variably controlled according to the time interval data determined sequentially. In other words, data specifying the scale is transferred from the CPU 100 to the frequency ROM.
8, and as a result, frequency data indicating the corresponding frequency is read out.

A musical tone signal is generated by being sent to the sound source circuit 9, and outputted from the sound system 10.

Further, the musical tone signals from the low-pass filters 3, . . . are applied to A/D converters 11, . . ., and are converted into digital data according to the waveform level thereof.

The outputs of the A/D converters 11... are latched by the latches 12.... The latch signal for this latch 12... is generated by the output of the flip-flops 14..., 15... via the OR gate 13...
Each time a maximum peak point or a minimum peak point is passed, a signal indicating the level of the waveform at that time is stored in the latch 12. Also, this orgate 13...
The latch signal LINL6 from . . . is also given to the CPU 100.

The output from the latch 12 is then given to the CPU 100, and the start and stop of sound generation, as well as the control of the output level (volume) of the output sound, etc., are performed in accordance with this output. Note that the peak values stored in the latches 12 . . . are sequentially written into the work memory 101.

That is, in the CPU 100, the A/D converter ll...
When the absolute value of the data indicating the waveform level given by ... exceeds a predetermined constant value, the sound generation of musical tones is started, and pitch (fundamental frequency) extraction is also started, and this data is set to a constant value. When the following occurs, a mute instruction is given to end the sound emission. The details of the operation will be described later.

In FIG. 1, the A/D converters 11 are provided independently in the pitch extraction circuits PI-P6, but -
Of course, it is also possible to use the /D converter in a time-sharing manner.
It is.

The frequency aROM 8 and the tone generator circuit 9 form a musical tone generation system of at least 6 channels by time-division processing.

Note that FIG. 2 shows a time chart of signal waveforms at each part in the pitch extraction circuit Pi, where ■ in the figure indicates the output of the low-pass filter 3, ■ indicates the output of the maximum peak detection circuit 4, and ■ indicates the minimum peak. The output of the detection circuit 5, ■ is the output of the zero cross point detection circuit 6, and ■ is the interrupt command signal I N Ta
l -I N Tab, ■ is the interrupt command signal I NT
b+-I NTbb.

The operation of this embodiment will now be explained. Figure 3 shows the CPU
100, and FIG. 4 is the main flow. Note that although FIGS. 3 and 4 only show the processing for one string, the processing for all strings is exactly the same, so if the CPU 100 executes the processing for each string at once, Just think about it.

Registers in Work Memory 101 Now, before explaining the specific operation of CPU 100, the main registers in work memory 101 will be explained.

The 5TEP register has four stages: 0, l, 2, and 3.
The string vibrates (Figure 5 (a) or Figure 6 (a))
(see), its contents change as shown in FIG. 5(b) or FIG. 6(b). When this 5TEP register is O, it represents a note-off (mute) state.

The 5IGN register indicates whether the zero-crossing point for period measurement is the zero-crossing point next to the maximum peak (MAX) point or the zero-crossing point next to the minimum peak (MIN) point. The latter is the case.

RE V E R S E Iy Schiff, 9 is the above 5
This is a register that stores data for checking whether or not interrupt processing has been performed due to the arrival of a zero-crossing point after the peak point on the opposite side of the zero-crossing point indicated by the IGN register. Used to check extraction control.

The T register stores the value of the counter 7 at a specific point for measuring the period of the input waveform. Note that the counter 7 performs a free running operation of counting at a predetermined clock.

The AMP(i) register stores the maximum or minimum peak value (
Actually, it is a register that stores the absolute value), and is a register that stores AMP (1
) is the register for the maximum peak, and AMP(2) is the register for the minimum peak.

The PERIOD register receives pitch data representing the latest measured period, and based on the contents of this register, the CPU 100 performs frequency control on the frequency ROM 8 and the tone generator circuit 9.

When setting new pitch data to the PERIOD register, the 0LDP register is set to the PERIOD register.
This register stores the same data as the previous pitch data set in the RIOD register.
If the previous pitch data and the latest pitch data in the PERIOD register do not substantially match, even if the current peak level value suddenly becomes larger than the previous peak level value of the input waveform signal, re-sounding will not be possible. Therefore, the process is controlled so that no processing is performed.

Furthermore, as will be described later, this embodiment uses three methods for various judgments.
One constant (threshold level) is CPU100
is set within.

The first one is 0NLEVI, Fig. 5(a),
As shown in FIG. 6(a), when the current note-off state is detected and a peak value larger than this value of 0NLEVI is detected, it is assumed that the string has been picked, etc., and the CPU 100 executes an operation for period measurement. starts execution.

0NLEv■ is a note-on (currently sounding) ym, and if the difference between the previous detection level and the current detection level is greater than this value, it is assumed that there has been an operation such as tremolo playing, and the sound is started again ( relative on, relative
on ) processing.

As shown in FIG. 8(a), 0FFLEV is in a note-on (sounding) state, and when a peak value below this value is detected, note-off (mute) processing is performed.

From the above explanation, it will be easy to understand the operations of the interrupt routine and main routine described below.

Interrupt Processing at Zero Cross Point Now, when the interrupt command signals INTa and INTb, which are the outputs of the AND gate 24 or the AND gate 25, arrive at the CPU 100, the interrupt process shown in FIG. 3 is performed.

That is, when the interrupt command signal I N T a is input,
First, the process of step P1 is performed, and the C register in the CPU 100 is set to 1. When the interrupt command signal lNTb is input, the C register is set to 2 by the process of step P2.
Set.

Then, in step P3, t in the CPU 100
Preset the value of counter 7 in the register. In the next step P4, the peak level data of the A/D converter 11 is read from the latch 12, and the CPU 100 reads the peak level data of the A/D converter 11 from the latch 12.
Set in the b register within.

Then, in step P5, the flip-flop 14
Or clear flip-flop 15.

In the following step P6, the contents of the a, b, and t registers are transferred and stored in the work memory 101, and the interrupt processing is ended.

△E31 In the main routine (Fig. 4), in step SI, the work memory 101 is
The contents of a', b', and t' are shown as a', b', and t' because they are the same as a, b, and t above, and were recorded last time.
It is judged whether or not it has been written, and if no interrupt processing is being performed, a NO judgment is made and this step Sl is repeatedly executed.

Then, if you make a YES decision in step 31 above,
Proceed to the next step S2 and read its contents a'.

Read out b', t' Next, in step S3, read out the peak value of the same type (that is, maximum or minimum) of the peak point stored in the AMP (a') register to the C register in the CPU 100; The peak value b' extracted this time is set in the AMP(a') register.

Now, first, in steps 54 to S6.

It is judged whether the contents of the 5TEP register are 3, 2, or 1, respectively. Now, if it is in the initial state, 5T
Since the EP register is O, steps Sa, Ss, S
A determination of No is made for both cases. And first step S
7, it is judged whether the peak value b' detected this time is greater than 0NLEVI.

If the peak value b' is smaller than 0NLEVI, the process returns to step S1 since the process of starting sound generation is not yet performed. Suppose that 0NL as shown in Figures 5(a) and 6(a)
If an input larger than EVI is obtained, step S
The determination in step S8 is YES, and the process advances to step S8.

Then, in step S8, 1 is set in the 5TEP register, first, in step S9, O is set in the REVER3E register, and then in step SIO, a' (that is, 1 at the zero cross point immediately after the maximum peak point. 1 immediately after the minimum peak point). When the zero crossing point of 2) is reached, input the value of 2) to the 5IGN register.

Then, in step Sl+, the value of t' is set in the T register. As a result, the contents of a' are stored in the 5IGN register (5IGN is 1 in the case of Figures 5(a) and 6(a)).
), the contents of b'(7) are set in the AMP register, and the contents of t' are set in the T register. Then, return to step S+ again.

Now, with the above explanation, the processing of the main routine immediately after the zero cross point Zero in FIGS. 5(a) and 6(a) is completed.

Now, next, the processing in the main routine immediately after the zero cross point Zero2 will be explained. In that case, step S above
1→S2→S3→S4→S5 data set processing and sound generation stage control processing are executed, and YES in the next step S6.
A determination is made, and the process then proceeds to step S12.

Now, when the waveform changes in the positive direction at the time of input as shown in Fig. 5 (a) and Fig. 6 (a), the 5IGN register is 1, and since it has passed the peak in the negative direction this time, the a register is 2, so the decision is NO. Incidentally, if a zero cross point arrives immediately after the peak value of the same polarity, a YES determination is made in step 512 and the process returns to step S1 without any further operation.

Now, in this step S12, the judgment is No, and the process goes to step 513, where the 5TEP register is set to 2. (See FIG. 5(b) and FIG. 6(b)).

Subsequently to step S13, step S1s is executed to compare the previous peak value (AMP (S IGN)) and the current peak value (b'). Now, as shown in Fig. 5(a), if the previous value C)) Execute steps 514 to 510, Sl+, and set the 5IGN register to 2.
At the same time, the contents of the t register are transferred to the T register.

On the other hand, if the previous peak value is larger than the current peak value, that is, if xl <
At step 5, the REVER3E register is set to l. In addition, 5I
The GN register will now maintain its previous value of 1. Therefore, in this case, the previous zero cross point (Zerol) is the starting point for period measurement (see FIG. 6(c)).

When the main flow is executed for the first time after passing the first-order zero cross point (Zero3), a YES judgment is made in step S5 and the process proceeds to step 516. This time a' is l, and in the case of FIG. , 5IGN is 2nd, 6th
In the case shown in the figure, 5IGN is 1, so in the case of Fig. 5, a NO judgment is made at step S+6, and the process goes to step 315 and returns to step S]. The CPU 100 recognizes that the peak (amplitude X2) has passed, and in the case of FIG.
I wonder if it's true or not. If it is not l, it is determined No and returns to step S+, but as mentioned above, step S
15, this register becomes 1, and the process goes from step SI+ to step 318 where the 5TEP register is set to 3 (see FIG. 6(b)), and then step SI+ is set to 1.
At step 9, the pitch data is obtained by subtracting the value in the T register, that is, the time of the zero cross point Zero, from the value of counter 7, which is accepted by the current interrupt, in the t register.
Store in PERIOD register.

In other words, the length shown in FIG. 6(C) is the length of one cycle, and in the subsequent step 320, the contents of E' are transferred to the T register to start a new cycle measurement.

Then, in step 521, the CPU 100 uses the contents of the above-mentioned PERIOD register to store the frequency ROM 8,
A sound generation command is issued to the sound source circuit 9, and therefore musical sounds are generated from this point onwards. Subsequently, the CPU 100 performs step S
At step 12, the pitch data set in the PERIOD register is set in the 0LDP register.

Now, in the case of FIG. 5 described above, the process jumps from step S5 to step S8 again in the main flow processing after the next zero cross point (Zero4). Now, 5
Since the IGN register is 2, the answer is YES in step S16.
Then, in the same manner as above, step S17 → 518
→ S19 → S20 → S month → Execute the sound generation start process of 332, and this time, the zero cross point Zero2 shown in FIG. 5(C) is executed.
The CPU 100 recognizes the period from zero to Zero4 as one cycle, and starts producing musical tones at a frequency based on this length (see FIG. 5(d)).

In this way, period measurement processing starts from the zero-crossing point next to the peak point with a large value, and ends at the zero-crossing point next to the peak point on the same side as the peak point, and the low-pass filter One period of the waveform of 3 outputs is extracted.

After this sound generation start processing, the main routine proceeds from step S4 to step S22, where it is judged whether the value of b', which is the peak value captured this time, exceeds 0FFLEV5i as shown in FIG. do.

If this level is exceeded, the process proceeds to step S24, where the contents of a' and the contents of the 5IGN register are compared for coincidence. If they do not match, the process proceeds to SI5 to prepare for interrupt processing at the next zero-crossing point; if they match, Since peaks with opposite characteristics (positive/negative peaks) have already been passed, the process proceeds to step S25, where it is judged whether the REVER5E register is 1 or not, and if No, the process proceeds to step SI without any processing. Returning, if in this step S25
If ES r4 is disconnected, the process advances from step S25 to step S26, and in order to obtain a new period (pitch), subtract the contents of the T register from the contents of the t' register to obtain the next pitch data, and set it in the PERIOD register. do.

Then, in step S27, the content IT of t
Transfer to the register, and then REVER in step S33.
The contents of the 3E register are set to 0, and the contents are set to 0L in step S34.
It is determined whether the previous pitch data in the DP register and the current pitch data in the PERIOD register substantially match.

Since they normally match, the CPU 100 proceeds to step S35 and judges whether relative on processing is to be performed. Specifically, it is judged whether the current peak value (b') is larger than the previous peak value (C) by 0NLEVU, that is, whether the extracted peak value suddenly became large during the sound generation.

Normally, if the string is vibrated, natural damping will occur, so the answer to step S35 is NO. However, if the string is operated again before the previous string vibration has finished damping due to tremolo playing, etc. The determination in step S35 may be YES.

In that case, a YES judgment is made in step S35, the process jumps to step S8, and steps 59 to SL
Execute the preparation process for starting the + sound.

As a result, the 5TEP register becomes 1, and the same operation as that at the start of sound generation described above is thereafter executed. In other words, the sound generation start processing of steps 316 to 321.532 is then executed again to perform the sound generation start processing again.

Now, in the normal state, as described above, step S35 is followed by step 536, and the CPU 100 performs frequency (pitch) control on the frequency ROM 8 and the tone generator circuit 9 based on the value of the PERI OD register.

In other words, in this embodiment, changes in the vibration frequency of the string are detected moment by moment, and frequency control is performed in real time accordingly.

Then, the process advances from step S36 to step S37, and P
The pitch data set in the ERIOD register is set to 0L.
Set in DP register.

Now, the overtone component of the input waveform signal is strong, and as shown in Figure 7(a), the levels of each part indicated by α and β within the - period gradually change and reverse as the sound emission time passes. Then, when the peak point of the chevron-shaped waveform β greatly exceeds the peak hold portion of α of the chevron-shaped waveform shown by the dotted line in FIG. 7(a), the peak level value an・5 of the chevron-shaped waveform β becomes , 0NLEVr for relative on (rl+pronunciation) for the peak level value an-4 of the previous chevron-shaped waveform α.
This may result in exceeding l.

However, as shown in FIG. 7(b), two maximum peak detection signals from the maximum peak detection circuit 4 now appear within one cycle. Then, step 3 within - period
26, the pitch extraction process in S27 will be performed twice, and the pitch data in the PERIOD register this time at the zero-crossing point immediately after waveforms a n and 3 will be the same as the one from α to β of the chevron-shaped waveform. Tn・2 is shorter than the period,
The pitch data in the previous 0LDP register is equal to the length of one cycle from α to α of the chevron-shaped waveform T n , l
becomes.

Therefore, in step S34 of the pitch extraction control process of steps 524 to S31 performed for each period of the input waveform signal, it is determined that the value of the PERIOD register and the value of the 0LDP register do not match, and step S
35. Since the process in S36 will be skipped, steps S35 and S8 to S will be turned on (re-sounding).
The processing in step S36 and the pitch control processing in step S36 are no longer performed. During this time, the musical tone continues to sound without change.

In this way, when the level of each part indicated by α and β within one period of the input waveform signal gradually changes and reverses as the sound emission time passes, the waveform level does not suddenly increase. Even if the picking operation is not performed, the re-sounding process is not performed, and it is possible to prevent an erroneous operation in which the re-sounding is performed even when no picking operation is performed. Further, since pitch control based on T n , 2 to T I + 4, which is shorter than one cycle, is not performed, a sound with a pitch different from the original sound is not emitted.

After this, the chevron-shaped waveform β becomes sufficiently larger than the chevron-shaped waveform α,
If the mountain waveform α sinks below the peak hold portion of the mountain waveform β, there will be only one maximum peak detection signal from the maximum peak detection circuit 4 in one cycle, and step 526, S2+ The pitch extraction process is performed once again within the - period, and the current pitch data in the PERIOD register matches the previous pitch data in the 0LDP register, and the pitch control process in step S26 is restarted. Become.

Then, as described above, when the string vibration is attenuated and the peak value falls below 0FFLEV as shown in FIG. The CPU 100 instructs the sound source circuit 9 to perform a note-off process (mute process) and mute the musical tones that have been generated so far.

In addition, in the comparison of the previous extracted pitch data and the current extracted pitch data in step S34, if the pitch data is 16 bits, the form of whether the upper 14 bits match or not and the difference between the pitch data of one car and the other are predetermined. It may also be in the form of whether or not the pitch data is below a certain value, and the target of comparison of the extracted pitch data this time is not the previous one,
In the above embodiment, in step 523, it is determined whether or not the waveform has suddenly changed based on the difference between the current peak value b' and the previous peak value C. For example, b'/c>S(
S may be a predetermined value of 1 or more) to determine whether or not the waveform has suddenly changed based on the ratio of peak values.

Furthermore, although the determination is made as to whether or not the waveform has suddenly changed by comparing the previous wave height value and the current wave height value, it may be determined by comparing the wave height values two times before and this time.

Further, when it is determined NO in step S34 of the above embodiment, the value of b' and C may be made the same before proceeding to step S35, and as a result, the relative-on processing may not be performed.

A sudden increase in the peak value during the generation of musical tones may be detected by detecting other conditions.

In the above embodiment, the CPU 100 performs interrupt processing at the zero cross point immediately after each peak point to perform processes such as starting sweating, calculating period, turning on relative, and starting muting. However, when each peak point is detected, These processes may be performed directly, and in that case, exactly the same results can be obtained.

In addition, for example, the same processing as described above may be performed by detecting a zero-crossing point immediately before the peak point, and the method of determining the reference point can be changed in various ways.

Further, in the above embodiment, each process is executed in the main flow, but similar processes may be executed in one interrupt process.

Further, in the above embodiment, the present invention is applied to an electronic guitar, but the present invention is not necessarily limited thereto, and pitch extraction may be performed from an audio signal or an electrical vibration signal input from a microphone, etc. Any type of system may be used as long as it generates an acoustic signal other than the rX audio signal at a corresponding pitch or scale frequency. Specifically, a system with a keyboard, such as an electronic piano, may be used. The present invention can be similarly applied to electronic wind instruments and electronic string instruments such as violins and kotos.

[Effects of the Invention] As described in detail above, the present invention provides a method in which the level of each part within one cycle of an input waveform signal gradually changes and reverses as the RF time elapses due to the influence of overtone components. In such cases, we focused on the fact that the pitch data extracted as one cycle of the waveform suddenly becomes smaller, and when the current pitch data no longer matches the past pitch data, the re-sound disclosure instruction is not issued. Therefore, even if the level of each part of the waveform gradually changes and reverses as the sound emission time passes, and the level of the waveform suddenly becomes thicker, re-sounding processing is not performed. Therefore, it is possible to prevent a malfunction in which re-sounding is performed even when no picking operation is performed, and effects such as making the sounding process of musical tones more reliable can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall circuit configuration of an input control device for an electronic musical instrument, which is an embodiment to which the present invention is applied, and FIG.
A time chart diagram showing waveforms etc. appearing in each part of the diagram,
3 is a flowchart of the CPU's interrupt routine, FIG. 4 is a flowchart of the CPU's main routine, FIGS. 5 and 6 are time charts showing the operation of each part at the start of sound generation, and FIG. FIG. 7 is a time chart showing an example in which an input waveform with a strong overtone component changes with the passage of sound emitting time, and FIG. 8 is a time chart showing the operation during muting. l...Input terminal, 4...Maximum peak detection circuit, 5...Minimum peak detection circuit, 6...
... Zero cross point detection circuit, 7 ... Counter, 9 ... Sound source circuit, 12 ... Latch,
14.15...Flip-flop, 100...
...CPU, 101...Work memory, P
i-P6...Pitch extraction circuit. Patent Applicant: Casio Kei' B Machine Co., Ltd. Figure 2 Figure 3
D Figure 5: The seventh stage of darkness

Claims (1)

[Claims] In an electronic musical instrument that extracts the pitch of an input waveform signal and generates a musical tone having a frequency based on the pitch, a detection means for detecting a change in the peak value of the input waveform signal; , an instructing means for giving a command to start generating the musical tone again when it is detected that the peak value has suddenly increased during the generation of the musical tone; and a measurement device for measuring a time interval corresponding to one cycle of the input waveform signal. means; storage means for storing pitch data corresponding to time intervals measured by the measuring means; past pitch data stored in the storage means;
a determining means for comparing the current pitch data measured by the measuring means and determining whether or not they almost match; 1. An input control device for an electronic musical instrument, comprising instruction inhibiting means for preventing a start instruction from being issued.