JPH0750395B2 - Input control device for electronic stringed instruments - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an input control device for an electronic stringed instrument such as an electronic guitar or a guitar synthesizer.

[Prior Art and its Problems] Various types of guitar-type electronic musical instruments have been conventionally developed. One of the important things in this kind of electronic stringed instrument is that it picks up the vibration of each string electrically, extracts the cycle (pitch) of the fundamental wave of the string vibration without error, and outputs it to the tone generator. To send a command.

However, the electric signal that represents the vibration obtained by picking up the string vibration and performing processing such as filtering usually contains harmonic components and noise, and these harmonics and noise are erroneously extracted as the cycle of the fundamental wave. Then, if frequency control is performed, a musical tone with a pitch that is extremely unnatural in terms of performance is generated.

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an input control device for an electronic string instrument that extracts the cycle of the fundamental wave of string vibration without error. .

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and a cycle extracting means for extracting a cycle of vibration of a string vibrating in a cycle corresponding to a pressed position, and the cycle extracting means are provided. Based on the extracted period, the pressed position determination means for determining the pressed position of the string, the amplitude detection means for detecting that the amplitude of the vibration of the string is equal to or more than a predetermined value, and the amplitude detection means When it is detected that the amplitude is equal to or more than the predetermined value, a tone generation instruction means for instructing the generation of a tone having a pitch corresponding to the cycle extracted by the cycle extraction means,
During the generation of the musical tone by the instruction of the musical tone generation instruction means,
When the cycle extraction means extracts a new cycle different from the cycle corresponding to the musical sound currently being generated, the pressed position determined by the pressed position determination means based on the new cycle, and the pressed position If the position difference between the pressed position corresponding to the currently generated musical tone that has already been determined by the position determination means is within a predetermined range, the musical tone generation instruction means causes the musical tone of the pitch corresponding to the new cycle. If the position difference is out of the predetermined range, the tone generation instruction means controls the tone generation so as not to instruct the tone generation with the pitch corresponding to the new cycle. The point is to have.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to the drawings.

★★ Structure ★★ FIG. 1 shows the entire circuit structure of the embodiment, showing the structure inside the body of a guitar-type electronic string instrument and the structure of the external circuit connected thereto.

In the figure, reference numeral 1 denotes the pitch extracting circuit for the first string, and the second to sixth strings are exactly the same, so only the pitch extracting circuit 1 for the first string is shown in the drawing.

Reference numeral 11 denotes a pickup, which converts the vibration of the first string into an electric signal. That is, in this embodiment, the independent pickup is provided for each of the six strings. Then, the output of the pickup 11 is applied to the filter 12 (low-pass filter) so that the higher-order overtone signal is removed. It is desirable that the cutoff frequency of the filter 12 be set to be different for each string in accordance with the range of the vibration frequency being different for each string.

The output of the filter 12 is applied to the filter amplifier 13, further appropriately filtered and amplified, and applied to the zero-cross comparator 14.

The details of the zero-cross comparator 14 are as shown in FIG. 2, in which the output of the filter / amplifier 13 is given to the capacitor 14-1 and becomes a signal, after which the operational amplifier 14− is supplied via the resistor 14-2. 3 is applied to the-terminal.

The resistor 14-2 has a center voltage level (the center level in the timing charts of FIGS. 4 and 5 described later, which is indicated by a chain line). Is applied through resistor 14-4. The above voltage level Is also given to the + terminal of the operational amplifier 14-3. The resistance ratio between the resistors 14-2 and 14-4 is preferably about 10: 1.

The output of the operational amplifier 14-3 is inverted and output by the inverter 14-5, and is given to the 1/2 frequency divider 15 in FIG. The zero-cross comparator 14 of FIG. 2 described above is used.
Is an example circuit, and other circuit modifications are possible.

The 1/2 divider 15 inverts the output level every time the output of the inverter 14-5 of the zero-cross comparator 14 rises, that is, every time the signal of falls, and divides the frequency by 1/2. The output of the 1/2 frequency divider 15 is a CP including a microprocessor for controlling the overall circuit operation of this embodiment.
It is supplied to the U100 and directly to the A counter 16 and to the B counter 17 via the inverter 18.

The A counter 16 and the B counter 17 are initialized when the respective applied signals rise, and count the clock pulse CLK only during the high level. In other words, the vibration waveform is 1/2
The time interval between the zero cross points of the waveform signal obtained by frequency division is measured. Then, the timing operation is stopped by the fall of the applied voltage, and the content is held until the next counting time.

Therefore, in this embodiment, the A counter 16 and the B counter 17 are
The time intervals between the respective zero-cross points are measured alternately.

Then, the count values of the A counter 16 and the B counter 17 are
It is supplied to the CPU 100.

Reference numeral 19 in FIG. 1 denotes a peak position and envelope detection circuit, which detects the peak position (positive maximum level position) of the output voltage signal of the filter 12 and obtains an envelope signal obtained by connecting the peak positions. Obtains (envelope signal) and supplies the respective signals to the CPU 100.

Details of the peak position and the envelope detection circuit 19,
As shown in FIG. 3, the signal from the filter 12 is supplied to the + terminal of the operational amplifier 19-1.
The output of 1 is applied to its-terminal via the diode 19-2, and the capacitor 19- via the resistor 19-3.
Given at one end of 4.

The voltage level above the other end of the capacitor 19-4 Is given. Therefore, the voltage signal provided through the diode 19-2 is charged only while the voltage signal is higher than the charge voltage of the capacitor 19-4, and otherwise discharged through the resistor 19-5.

The output of the operational amplifier 19-1 is passed through a resistor 19-6,
It is given to the-terminal of operational amplifier 19-7. Further, the resistor 19-6 is connected to the voltage level via the resistor 19-8. And the voltage level at the + terminal of the operational amplifier 19-7. Or connected. It is desirable that the resistors 19-6 and 19-8 have the same resistance value. The output of the operational amplifier 19-7 becomes a signal indicating the peak position and is supplied to the CPU 100.

The output of the resistor 19-5 is given to the-terminal of the operational amplifier 19-9, and the positive terminal thereof has the above voltage level. Is given. The output of the operational amplifier 19-9 is returned to the-terminal via the resistor 19-10, and
It is output as an envelope signal via the resistor 19-11. The peak position and envelope detection circuit 19 shown in FIG. 3 is one example circuit, and may have other configurations.

The CPU 100 time-division-multiplexes six strings by the CPU 100 as described later, gives them to the A / D converter 7, converts them into digital signals, and then starts sound generation,
It is used in various processes such as muffling start process.

This A / D converter 7 performs an analog-digital conversion process on a given analog signal and then sends an A / D end signal to the CPU.
Supply to 100. The CPU 100 accepts this A / D end signal as a normal process in the process of the main routine, or accepts it by an interrupt. Details are as described later. In addition, this A / D converter 7
It may be a chip separate from 0 or may be an A / D converter inside a one-chip microcomputer.

The CPU 100 executes various processes in cooperation with the buffer memory 8. Further, numeral 9 in FIG. 1 is a number counter. That is,
When the CPU 100 detects that the vibration of any one of the plurality of strings has changed from being lower than a predetermined level to being higher than the predetermined level for the first time, the counter 9 outputs a predetermined number of times. Extracts the period of the fundamental wave of only the vibration of the string whose vibration amplitude has newly exceeded the specified level, and the fundamental wave of the vibration of the other strings (strings other than the string whose vibration amplitude has newly exceeded the specified level) Skip so that the cycle of is not extracted. It counts the number of times. As a result, the pitch at the start of vibration of the picked strings can be concentratedly extracted.

Further, 101 in the figure is an ON counter, and this ON counter 101
Is for setting the musical tone to the pitch corresponding to the cycle when the frequency information determines that the cycle information has a match within a semitone within a predetermined number of times, as will be described later. When a match is detected, the preset value is counted down. When it becomes zero, a musical tone is generated at the pitch corresponding to the extracted cycle. Alternatively, the pitch of the musical sound that has already been pronounced is changed.

Therefore, the pitch of the output musical tone can be determined and the pitch can be changed without error.

The CPU 100 is also connected to the MIDI interface 10. This MIDI is Musical Instrument Digital Int
Abbreviation of erface, which is a unified standard for connecting musical instruments and personal computers with musical instruments. Of course, an interface using a format other than this MIDI format may be used.

Then, via the MIDI interface 10, to the external sound source module 200, which is a sound source unit outside the guitar, outputs a sounding control command, a mute control command, and a pitch change command,
Instructing the external tone generator module 200 to generate musical tones in accordance with the performance operation of strings and frets.

★★ Operation of pitch extraction circuit ★★ Next, the operation of the pitch extraction circuits 1 to 6 of the present embodiment will be described.

Before describing the details, the basic method of pitch extraction of this embodiment will be described first.

The output of the zero-cross comparator 14 that is inverted every time the vibration waveform passes through the zero-cross point is divided by the 1/2 divider 15, and the A counter 16 and the B counter 17 perform counting operation as described above for each change in the output level. Alternately.

Then, when the peak point of the vibration waveform is detected by the peak position and the envelope detection circuit 19, the measured counter value is added as necessary in the time from the previous peak point to the current peak point. Then, the time length of one cycle of the waveform is calculated. This calculation is performed by CPU100.

Therefore, the period of the fundamental wave of the vibration of the string generated by picking or the like can be extracted by using either one or two of the count values of the A counter 16 and the B counter 17.

FIGS. 4 and 5 show internal timing charts of the pitch extraction circuit 1. When the waveform signal shown in FIG. 4 does not include overtones, the waveform signal is output through the filter 12, and FIG. Shows the operation of each part when the waveform signal when the second harmonic is included is being output through the filter 12.
Note that the overtones higher than that are removed by the filter 12 and the filter amplifier 13. Therefore, the zero-cross comparator
A waveform signal containing a fundamental wave representing vibration or a harmonic wave form up to a second harmonic is given to 14. As will be described later,
The processing of the CPU 100 also performs the processing of removing overtones.

4 and 5 show the output of the filter 12 of FIG. And this waveform signal is given to the peak position and envelope detection circuit 19, each time a voltage signal of a level exceeding the charging voltage of the capacitor 19-4 is given,
The capacitor 19-4 is charged through the operational amplifier 19-1, the diode 19-2, and the resistor 19-3, and is discharged through the resistor 19-5 when passing the peak position. As a result, the capacitor 19- The output voltage of No. 4 is as shown in FIGS. 4 and 5.

Therefore, the envelope signal output through the operational amplifier 19-9 and the resistor 19-11 is as shown in FIGS.

Further, due to a change in the output of the operational amplifier 19-1, the operational amplifier 19-7 falls at the start of charging the capacitor 19-4 and at the end of charging, that is, at the positive peak position of the vibration waveform. The signal shown in FIG. 5 is output. This becomes the peak position signal shown in FIG.

Furthermore, the output signal of the filter 12 is the filter amplifier 13
At, the level is inverted, filtering and amplification are appropriately performed, and the result is given to the zero-cross comparator 14.
Capacitor 14-1 inside the zero-cross comparator 14
The output (see FIG. 2) is as shown in FIGS. 4 and 5.

Then, this signal is as shown in FIG. 4 and FIG. 5 in which the level is inverted every time it passes through the zero cross point through the operational amplifier 14-3, and the inverted output of this signal is the inverter.
Supplied from 14-5.

Therefore, the A counter 16 is reset at the rising edge of the output (FIGS. 4 and 5) obtained by dividing the signal by the 1/2 frequency divider 15 and measures the clock signal CLK until the signal is inverted. Then, after the measurement is completed, the measured value is held.

The B counter 17 performs the counting operation opposite to that of the A counter 16. That is, the B counter 17 measures the clock signal CLK until the signal is reset and inverted when the signal falls. Then, after the measurement is completed, the measured value is held.

Therefore, when the waveform signal containing only the fundamental wave as shown in FIG. 4 is given from the filter 12, as can be understood from FIG.
Only one of the counters 17 measures once. Therefore, the CPU 100 reads the output of each counter after the measurement is completed, and at the time of peak detection, the counter value detected from the previous peak to the current peak, or one value in the case of FIG. 4,
It will be the period of the fundamental wave as it is.

In order to improve the accuracy of pitch extraction and prevent malfunction due to noise or the like, the pitches extracted in the previous time and before are compared with each other within a predetermined error range. The vibration frequency is determined only when a match of (in) is detected.

Now, as shown in Fig. 5, the waveform signal that produces the overtone is
As will be understood from FIG. 5 when given from 12, both the A counter 16 and the B counter 17 alternately measure once in one cycle of the waveform.

Therefore, in CPU100, the counting contents of each counter is
The output signal of the frequency divider 15 is read every time it is inverted, and when the peak position is detected, the counter value detected from the previous peak to the current peak, that is, the two counter values of the A counter 16 and the B counter 17 are added. Then, it becomes the period of the fundamental wave.

★★ Operation of whole circuit, especially operation of CPU ★★ Next, the operation of the whole circuit of this embodiment will be described in detail.

FIG. 6 is a flowchart showing the operation of the CPU 100,
In the main routine, the process of reading the count values of the A counter 16 and the B counter 17 for each string and the A / D conversion process of the envelope signal are mainly performed.

That is, step S1 is a routine for initialization after power-on, and in this step S1, registers and buffer memory 8 inside CPU 100, number counter 9, ON counter 101
Make initial settings such as.

Next, steps S2 to S6 are a routine for reading the contents of the A counter 16 and the B counter 17 of the first string. In step S2, it is judged whether the envelope value of the first string exceeds the threshold value. To do. The envelope value is a value obtained by converting the peak position and the envelope signal output of the envelope detection circuit 19 into a digital value by the A / D converter 7. The order of A / D conversion of the envelope signal of each string will be described later.

Then, in this step S2, when it is detected that the envelope of the first string does not exceed the threshold value (that is, the vibration level is small), it is determined that the string is not picked, and NO is determined. Proceed to step S7.

If the string continues to vibrate after being repelled, the process proceeds from step S2 to step S3, and the number counter 9
Judge whether is 0 or not. The number counter 9 is set to an initial value other than 0 when any string is newly picked. If a certain period has passed since the start of the string vibration, the content of the number counter 9 becomes 0 as described later.

Therefore, when the number counter 9 is other than 0, that is, when the value is equal to or less than the initial value and is 1 or more, the CPU 100 determines NO, and in the next step S4, the relevant string (first string in this case). The external sound source module 20
At 0, judge whether or not the sound is being continued. If YES is determined, it is determined that the pitch extraction processing of the string is not urgent, and the steps S4 to S7 are performed.
Go to.

Then, if NO is determined in step S4 or YES is determined in step S3, the process proceeds to step S5, and the output of the 1/2 frequency divider 15, that is, the output of FIGS. 4 and 5 is output. It detects whether or not it has been inverted.

If NO is determined in step S5, the process proceeds to step S7 without any processing. If YES is determined in step S5, the contents of the A counter 16 or the B counter 17 are changed in step 6. The CPU 100 reads and transfers and stores it in the buffer memory 8.

In this case, the CPU 100 reads the contents of the A counter 16 when the signal falls, and reads the contents of the B counter 17 when the signal rises, as described above.

Then, the reading processing of the A counter 16 and the B counter 17 of the first string is completed, and the process proceeds to step S7. In step S7, the same processing as that of the first string (steps S2 to S6) is performed for each of the second to sixth strings, and step S8 is performed.
Go to.

A step S8 judges whether the number counter 9 is 0 or not.
If it is not 0, the process proceeds to step S9, the content is down-counted, and then the process proceeds to step S10. If YES, go to step S10 without processing anything. Therefore, if the number counter 9 is other than 0, it is down-counted by 1 each time the main flow is executed once.

Then, in step S10, the A / D conversion end signal of the A / D converter 7 is attached by an interrupt (interrupt) to control execution of the subsequent processing, or after step S10, normal processing is performed and AD conversion is performed. Select whether to perform the process.

In this case, if the A / D conversion end signal is received by interruption and processed, AD conversion of the envelope signal of each string can be performed at high speed. That is, the A / D converter 7 performs AD conversion of the envelope signals of the strings one after another without any rest time.
For example, when the start of vibration of one string is detected, there is a high possibility that other strings will be picked at the same time, and an interrupt (interrupt) after AD conversion is accepted.
Then, the process returns from step S2 to permit acceptance of the interrupt process in steps S2 to S9 of the main routine.

If the AD conversion interrupt is masked, the process proceeds to step S11 following step S10, and the A / D end signal is already given from the A / D converter 7, and the envelope of the selected string vibration is displayed. Judge whether A / D conversion is completed.

If NO, the process returns to step S2, the steps S2 to S10 are executed, and the step S11 is checked again.

Then, if YES is determined in this step S11,
In step S12, the CPU 100 receives the A / D-converted digital signal as the value of the envelope signal of the selected string and stores it in a predetermined area of the buffer memory 8. This envelope value is used in the steps corresponding to step S2 in step S2 and step S7 described above.

Then, following step S12, in step S13,
If new picking is done or not, it is judged based on the extracted envelope value, that is, it is judged whether or not the predetermined threshold level is exceeded, and if YES, step S
Proceed to 14 and set a predetermined value in the number counter 9. As described above, the number of times corresponding to the set value is newly added to the string vibration, the counter reading process for the string before the start of sound generation (step S6) and the pitch extraction and sound generation control process (step T3) described later are performed. And other strings (that is, strings other than the string before the start of sounding due to new string vibration) (that is, the process of reading the counter [step S6], the pitch extraction and the sounding). Strictly speaking, since the control process [step T3] is skipped, step S6 is executed when YES is determined in step S5, and therefore the priority of the counter reading process is the number of times. It may be smaller than the set value for the counter 9.

After this step S14, turn on the counter in step S15
The initial value is set in 101, and the scale information (scale information in semitone units) stored in a predetermined area of the buffer memory 8 as the extracted pitch based on the previous string vibration is cleared.

In this step S15, the initial setting for pitch extraction has been made. Since the initial setting of the ON counter 101 is also performed in step T11 described later, it is not always necessary, but in order to promptly determine the pitch at the start of sounding, the processing as shown in step S15 is performed. It is desirable to do.

Following this step S15 or if NO is determined in step S13, the process proceeds to step S16 to start AD conversion of the next string. That is, in order to AD-convert the envelope signals of the first string to the sixth string, when the AD conversion of the envelope signal of one string is completed, the AD conversion of the envelope signal of the next rank is started.

Then, after returning to step S16, the process returns to step S2, and the processing of the main routine is repeated in the same manner.

Next, the interrupt processing when the peak position signal output from the peak position and envelope detection circuit 19 arrives will be described.

When this signal rises, the output waveform signal of the filter 12 comes to have a positive peak position (see FIGS. 4 and 5).
(See the drawing), the CPU 100 temporarily interrupts the processing of the main routine, and first performs the processing of step T1.

In step T1, it is determined whether or not the number counter 9 is 0, and if it is 0, the process proceeds to step T2, and it is judged whether or not a musical sound is being generated corresponding to the string. If YES,
Processing for the string is not urgent and returns to the main routine. If NO in step T2, the CPU 100 has already read A in step S6 as described below.
According to the count value of the counter 16 or the B counter 17, the pitch is extracted by appropriately adding, and if a predetermined condition is satisfied, the tone generation control process of the musical tone of the corresponding pitch is performed, and the MIDI tone is generated.
A predetermined command is output to the external sound source module 200 via the interface 10. In this case, since the pitch at the start of sounding is determined based on the result of multiple times of pitch extraction, a new string vibration is preferentially performed and the process for the string before the start of sounding can be performed (that is, other than that. The extraction of the pitch of the string of [the string other than the string before the start of sounding due to new string vibration] and the reading processing of the A counter 16 and the B counter 17 are skipped, and the processing for the string at the start of sounding is repeated. It is effective.

That is, if NO is determined in step T2 or YES is determined in step T1, the counter value read from the previous peak to the current peak is added in step T3 to calculate the string vibration. Get the value of the period.

In this case, in the example of FIG. 4, the period of the fundamental wave is determined by the counting result of only one of the A counter 16 and the B counter 17 from the peak position to the peak position, and in the example of FIG. The period of the fundamental wave is determined by the added value of the counting results of both B and B counter 17. This is as described above.

Then, in the next step T4, the CPU 100 searches the scale table (recorded as a table in the CPU 100 in FIG. 1) from the value of the period obtained in step T3, and scale information (corresponding to the string vibration) Obtain information in semitone steps. In addition, the frequency information of less than a semitone is obtained, and step T1 described later is performed.
It is more effective when used when performing frequency control in 5.

Next, in step T5, the CPU 100 determines whether or not there is a string that is already sounding.
The buffer memory 8 is searched and checked. Then, if there is a string that is already sounding, the answer is YES, and in the next step T6, the fret number of the string operated this time is calculated. Then, the process proceeds to step T7, and it is judged whether the content of the number counter 9 is 0 or not.

If the string or another string is vibrated, and the sound generation start command for the string is not yet output to the external tone generator module 200, that is, if the frequency counter 9 is not 0, it is determined NO in step T7 Go to T8.

In step T8, the fret number of the string detected this time is equal to the fret number of the string which is already being sounded and which has been operated most recently (this is read from the buffer memory 8).
Determine if the difference is within 5 frets.

The value of the fret difference of ± 5 is not necessarily limited to this value, but when performing a normal performance with a human finger, while operating a fret with a string, which is one finger, with another finger. It refers to the range of fret positions on other strings that can be reached by operation.

Then, if it is within the range, YES is given and the processings after step T9 are continuously executed, but if it is outside the range and NO is given, the process returns to the main flow. In other words, when it is detected that the previous operation fret exceeds ± 5 frets, this is because the CPU 100 judges that the A counter 16 and the B counter 17 have erroneously extracted the overtone cycle,
You can change the scale information that has been extracted so far, or use the ON counter
This interrupt process is terminated without initializing 101.

When it is detected in step T5 that there is no sounding string, when it is detected in step T7 that the number counter 9 is 0, and when it is determined YES in step T8. Then proceeds to step T9. At step T9, the scale information of the string operated this time is recorded in a predetermined area of the buffer memory 8.

The scale information written in this step T9 is used in the next step.
Used in T10. That is, the scale information (semitone unit) written in the same manner as the previous time is compared with the scale information (semitone unit) written this time, and whether or not they match, that is, whether or not the extracted cycles are within a semitone or not. To determine. If NO is determined, the ON counter 101 is initialized (step T1
1). That is, the coincidence comparison of pitch extraction is performed again from the beginning.

If YES is determined in step T10, the process proceeds to step T12, and it is checked whether the ON counter 101 is 0. If not 0, go to step T13 and turn ON counter 1
Decrement (-1) 01 and see if it became 0 at step T14.

If YES is determined in step T12 or step T14,
In step T15, the tone generation / frequency control command is transferred to the external tone generator module 200 via the MIDI interface 10 to control the generation of the musical tone of the corresponding pitch. In this case, at the start of sounding, the sounding may be started by the frequency information in semitone steps, and thereafter, the pitch of the musical tone may be determined in consideration of the frequency information of a semitone or less. Alternatively, the pitch control of the musical tone may be performed by reflecting the frequency information of a semitone or less from the beginning.

Then, in this step T15, the fret number extracted this time is further stored in a predetermined portion of the buffer memory 8. This fret number is stored only for the latest one of the operated strings, and the step T8 during the subsequent interrupt processing is performed.
Used in.

Then, after the processing of step T15, or when NO is determined in step T14, the process returns to the main flow even if the interruption is completed.

In the drawing, the ON counter 101 is judged whether it is 0 or not, but it is judged by whether or not the borrow comes out from the ON counter 101, and when the borrow comes out, the ON counter 101 is set to zero and step T15 is executed. However, if there is no borrow, steps T12 to T14 may be changed so as to return to the main flow without executing step T15. Such changes are self-evident.

As described above, the number counter 9 is set to 0 after the start of sound generation.
In the case of, at the time of this interrupt processing, step T15
If the above conditions are satisfied in the
External sound source module 20 via DI interface 10
It is sent to 0 and the pitch change control is performed according to the frequency change of the string vibration. When the string vibration is attenuated, mute control is also performed at this step T15.

Therefore, in the main routine, while the count value corresponding to the vibration period of each string is detected by the CPU 100, by executing the interrupt processing T1 to T15, the generation control of the musical sound of the pitch is performed by the external sound source. Performed on module 200.

Each step of U1 to U5 in FIG. 6 is performed by the A / D converter 7 to A.
The details of the interrupt routine in the case of accepting and processing the / D end signal by the interrupt are shown, and the processing is effective when the A / D interrupt is enabled (NO in the determination in step S10).

Since the contents of the processing of each step are exactly the same as those of steps S12 to S16 of the above-mentioned main routine, the description thereof will be omitted.

As described above, according to this embodiment, the ON counter 10
For the down count operation of 1, if it is detected that the fret position of the string extracted this time and the fret position of the string that is already sounding are separated by more than ± 5 frets (step
(No judgment at T8) does not have any effect, and prepares for the next period extraction, and does not use this erroneously extracted period information for subsequent scale comparison (step T10) (from step T8). It returns without going through step T9). Therefore, at the start of sound generation (when the number counter 9 is not 0), pitch extraction can be performed quickly.

In FIG. 6, if it is assumed that steps T5 to T8 are not performed, the ON counter 101 is initialized again when the cycle of higher harmonics is erroneously extracted and the cycle of the previous extraction does not match. However, there is a problem that it takes time to determine the pitch at the start of sounding, and the responsiveness at the start of sounding deteriorates.

In an extreme case, when steps T5 to T8 are not performed, when the cycle of the higher harmonics is erroneously detected continuously for the number of times corresponding to the initial set value of the ON counter 101, the musical sound of the pitch corresponding to the cycle is detected. Will occur.

By making a comparison between the fret number of the string that has been sounded so far and the fret number of the string this time in step T8, it is possible to eliminate such a judgment error.

The present invention can be variously applied other than the above-mentioned embodiments.

For example, the above embodiment is an electronic guitar of a type in which six strings are provided on the body, but it is also applicable to other types of electronic string musical instruments.

Further, in the above embodiment, the zero cross comparator
Although the pitch is extracted by the period data obtained based on the detection of the zero cross point by 14, the pitch may be extracted by a method other than that, for example, by detecting the interval between the maximum peak values.

Further, in the above embodiment, the number of times of processing of the main routine is counted by the number counter 9 to ensure the centralized processing at the start of sound generation, but the same may be done by other means. For example, this may be achieved by counting the time, that is, the time may be counted for a certain period, and the centralized processing may be guaranteed during that time.

In addition, in the above-described embodiment, at the start of sound generation (number counter 9
Is not 0) only, the step T8 is performed to compare the fret operation position of the already-pronounced string with the fret operation position corresponding to the extracted period, and the processing form is appropriately changed according to the comparison output. Alternatively, such processing may be performed regardless of the content of the frequency counter 9.

In addition, in the above embodiment, when the string is newly picked, step S14 or step U3 in FIG.
In step 1, the number counter 9 is set to a predetermined value, and the count values of the A counter 16 and the B counter 17 for the strings to be picked to start sounding are read (step S6) and pitch extraction is performed a number of times corresponding to the value. The calculation process for steps (steps T3 to T15) is preferentially executed by not performing the same process for other strings (that is, strings other than the strings that are picked and should start sounding).

However, if you slightly instruct the vibration of the strings by the tremolo playing method by slightly changing the processing flow of the CPU 100,
It is possible to deal with the re-pronunciation start processing in the same manner.

That is, for example, step S13 or step U2 (sixth
(See the figure), (i) when a non-vibrating string is newly picked and the output level of the corresponding electric signal exceeds a predetermined level, and (ii) when vibration is occurring but the time after picking is Two conditions are detected, that is, when the string whose output level of the electric signal has fallen due to the vibration is picked again and exceeds the predetermined level again. In each case, step S13 is detected. From step U2 to step S14 or step U3, a predetermined value may be preset in the frequency counter 9 as described above.

If the flow is changed, step S4,
In step T2, (i) the string is not vibrating, and therefore no musical sound is generated, and (ii) the threshold level is reached again after the volume level falls below the predetermined value even during sounding. Detecting that both values are exceeded, make a NO determination in step S4 and step T2, and then execute steps S5, S6 or steps T3 to T15.
The processing content may be changed.

[Effects of the Invention] As described in detail above, according to the present invention, the pressing position of the string obtained by extracting the vibration cycle of the string is the pressing position of the string corresponding to the musical sound that has been produced until then. If there is a large difference, it is considered that it can not occur in normal operation, it is considered that overtones or noises are extracted as the basic waveform, and it is not instructed to start the generation of the musical sound of the frequency at the fret position. The noise at the time of extraction can be strongly removed, and the generation of musical tones with incorrect pitch can be prevented, which is convenient for performance.

[Brief description of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a diagram showing a circuit configuration of the embodiment, FIG. 2 is a detailed circuit diagram of the zero-cross comparator of FIG. 1, and FIG. 3 is a peak position. FIG. 4 is a detailed circuit diagram of the envelope detection circuit, FIGS. 4 and 5 are timing charts showing the operation of the embodiment, and FIG. 6 is a flow chart showing the operation of the embodiment. 1-6 ... Pitch extraction circuit, 7 ... A / D converter, 9
…… Count counter, 14 …… Zero cross comparator, 15
...... 1/2 divider, 16 ... A counter, 17 ... B counter, 19 ... Peak position and envelope detection circuit, 100
...... CPU, 101 …… ON counter, 200 …… External sound source module.

Claims (1)

[Claims] 1. A cycle extracting means for extracting a cycle of vibration of a string vibrating in a cycle corresponding to a pressed position, and a pressing position of the string is determined based on the cycle extracted by the cycle extracting means. The pressed position determining means, an amplitude detecting means for detecting that the amplitude of the vibration of the string is equal to or more than a predetermined value, and the amplitude detecting means detects that the amplitude is equal to or more than the predetermined value, the cycle A tone generation instruction means for instructing the generation of a tone having a pitch corresponding to the period extracted by the extraction means, and during the tone generation by the instruction of the tone generation instruction means,
When the cycle extraction means extracts a new cycle different from the cycle corresponding to the musical sound currently being generated, the pressed position determined by the pressed position determination means based on the new cycle, and the pressed position If the position difference between the pressed position corresponding to the currently generated musical tone that has already been determined by the position determination means is within a predetermined range, the musical tone generation instruction means causes the musical tone of the pitch corresponding to the new cycle. And the position difference is outside the predetermined range, the tone generation instruction means controls so as not to instruct the tone generation with the pitch corresponding to the new cycle. An input control device for an electronic stringed instrument, comprising: