JPH08185160A - Electronic stringed instrument and string vibration detecting device - Google Patents

Abstract

PURPOSE: To simplify constitution and to rapidly attenuate a generated musical sound by touching to a string when a signal out of the range of a prescribed level is outputted continuously from a string vibration detection means by performing muffling instruction. CONSTITUTION: Whether a value of DATA storing an A/D conversion value of a photodiode corresponding to CH lies on the plus side or the minus side of INZ (CH) ±β is detected. When it is DATA>INZ (CH) +β and lies on the plus side, whether or not it is in the state of PLS (CH) = 1 at this time is discriminated. When it is PLS (CH) = 1, since the state of DATA>INZ (CH) +β is continued from before, whether or not the value of TIM (CH) counting the duration of DATA>INZ (CH) +β becomes γ or above is discriminated, and when it becomes TIM (CH) > γ, muffling processing is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic stringed instrument, and more particularly to muffling control for an electronic stringed instrument.

[0002]

2. Description of the Related Art As a conventional electronic stringed instrument, for example, an electronic guitar disclosed in Japanese Utility Model Laid-Open No. 1-164496 is known. The neck of this electronic guitar is provided with fret switches corresponding to six strings for each fret. Further, a simulated string is stretched on the body, a pickup is arranged below the string, and a touch detection circuit is provided at one end of each string. When one of the fret switches is pressed and the corresponding string is picked, the pickup detects the vibration of the string and the detection of this string vibration triggers the pitch specified by the operation of the fret switch. To instruct generation of musical sound. Further, when the vibrating string is touched with a finger, the touch detection circuit detects this touch, and in response to this touch detection, an instruction to mute is given. Therefore, by touching the strings with the right hand used for picking, it is possible to perform a playing method in which the generated musical sound is rapidly attenuated as in the acoustic guitar.

[0003]

However, in such a conventional electronic guitar, by providing a touch detection circuit separately from the pickup for detecting the vibration of the strings, the mute in response to the touch on the strings is suppressed. Is configured to direct. Therefore, the need for the touch detection circuit causes a cost disadvantage, and since the touch detection circuit must be provided for each string, the number of parts and the number of assembling steps increase.

The present invention has been made in view of the conventional problems as described above, and provides an electronic string instrument capable of issuing a mute instruction in response to a touch on a string without providing a touch detection circuit. That is the purpose.

[0005]

In order to solve the above-mentioned problems, an electronic musical instrument of the present invention is provided with a string vibration detecting means for outputting a signal of a level according to the distance to the string, and a string vibration detecting means. When the output signal level of the string vibration detecting means is changed accordingly, a tone generation instruction means for instructing the generation of a musical sound and a signal outside the predetermined level range are continuously output from the string vibration detecting means, The gist is that a mute instructing means for instructing the mute of a musical sound is provided. Further, the string vibration detecting device of the present invention includes a reflecting member provided on the string and having a width wider than the diameter of the string, a light source for irradiating the surface of the reflecting member with light, and the reflection by the light source. The gist is that the light receiving means receives the light reflected by the surface of the member and outputs a signal according to the light receiving state.

[0006]

In the electronic musical instrument having the above-mentioned structure, when a string is vibrated to vibrate the string, the distance between the string that started the vibration and the string vibration detection means changes periodically according to the vibration cycle of the string. Therefore, the string vibration detecting means outputs a signal whose level changes periodically, and in response to this signal whose level changes periodically, generation of a musical sound is instructed. When the vibrating string is pressed with a finger, the string stops vibrating and, depending on the distance between the position of the pressed string and the string vibration detection means, the string vibration detection means outputs a predetermined level or more. A signal below a predetermined level, that is, a signal outside the predetermined level range is continuously output. Then, the muffling instructing means responds to the continuously output signal outside the predetermined level range to instruct the muffling, so that the musical tone generated by the string is muffled by pressing the string.

Further, in the string vibration detecting device having the above structure, since the reflecting member having a width wider than the diameter of the string is provided, the reflected light from the string (reflecting member) can be satisfactorily detected.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. That is, this embodiment applies the present invention to an electronic guitar, and as shown in FIG.
It is composed of a body 2 and a neck 3 whose one end is fixed to the body 2. Neck 3 has multiple frets 4
.. are provided, and between each fret 4 ... Between them are 6 ridges 5 imitating the 6 strings stretched on the guitar.
Each is formed. Further, the neck 3 is provided with a fret switch portion 6. The fret switch section 6 is a fret switch arranged corresponding to the six ridges 5 between the frets 4, that is, 6 in the present embodiment.
It has 90 fret switches formed by a 6 × 15 matrix, which is 15 frets for a string, and each fret switch is a normally open type switch that is turned on by pressing the ridge 5.

The body 2 is provided with a slit portion 16 for emitting a musical sound generated from a speaker arranged inside, a body switch portion 17 and a volume switch 18. The body switch unit 17 includes a tone color setting switch 19 for setting the tone color number by incrementing or decrementing the tone color number according to the operation, and a filter operated when changing the filter coefficient in the filter unit described later. A switch 20 is provided.

Further, the body 2 is provided with a front bridge 7 arranged in the vicinity of the neck 3 and a rear bridge 8 facing the front bridge 7 with a space therebetween, and between the both bridges 7, 8. Only 6 mimic strings 9 are stretched on the chisel. The rear bridge 8 is provided with a cover 10 as shown in an enlarged view in FIG.
In the portion extending in the cover 10, a columnar member 11 is provided and a coil spring portion 12 is formed. This coil spring part 12
Has a predetermined contracting force and generates a tension on the simulated string 9 which is similar to that of a string stretched on a general guitar. Further, the columnar member 11 is fixed to the string 9 on the central axis with its peripheral surface oriented in the direction of the string 9, and immediately below the columnar member 11 is a string vibration detecting means. The photo sensor 13 is fixedly arranged corresponding to each string 9.

Each of the six photosensors 13 has a light source section 14 and a photodiode 15 shown in the block diagram of FIG. And the light source unit 1
Numeral 4 irradiates a predetermined area on the lower peripheral surface 11a of the cylindrical member 11 with light, and the photodiode 15 has the light source unit 16
The light that is further irradiated and reflected by the lower peripheral surface 11a is received. Therefore, when the columnar member 11 is stationary with the strings 9, the photodiode 15 receives substantially constant reflected light from the lower peripheral surface 11a. Therefore, when the string 9 is at rest, as shown in FIG.
Also, as indicated by INZ (CH) in FIG. 4, the output level of the photodiode 15 is also substantially constant.

Further, when the string 9 is pressed by the finger at the time of starting the strung string, the string 9 is pushed by this, and the columnar member 11 is displaced downward accordingly, and the columnar member 11 and the photo The distance to the diode 15 is reduced. This allows
The light reflected from the lower peripheral surface 11a is reflected by the photodiode 15
The amount of dispersed light to the surroundings is relatively reduced, and the amount of incident light on the photodiode 15 is increased. As a result, the output level of the photodiode 15 rises according to the string pressing force at the start of the stringing, as shown by "PS" in FIGS.

Further, when the string 9 starts vibrating by striking a string, the distance between the columnar member 11 and the photodiode 15 is repeatedly increased and decreased in synchronization with the vibration of the string 9. At this time, when the distance between the cylindrical member 11 and the photodiode 15 increases, contrary to the above, the reflected light from the lower peripheral surface 11a has a relatively large amount of dispersed light around the photodiode 15, and The amount of light incident on the photodiode 15 is reduced. As a result, the output level of the photodiode 15 is the output level INZ when the string is stationary.
(CH) much less. Therefore, when the string 9 continues to vibrate, the cylindrical member 11 and the photodiode 1
Since the distance to 5 increases or decreases in synchronization with the vibration cycle of the string 9, the output level of the photodiode 15 also increases or decreases in synchronization with the vibration cycle of the string 9, as shown in FIG. .

When the vibrating string 9 is pressed with a finger, the string 9 stops vibrating, and the cylindrical member 11 is displaced downward due to the pressing, so that the cylindrical member 11 and the photodiode 15 move. Distance is reduced. As a result, in the same manner as described above, the amount of reflected light from the lower peripheral surface 11a is relatively reduced in the amount of dispersed light around the photodiode 15, and the amount of light incident on the photodiode 15 is increased. As a result, the output level of the photodiode 15 becomes higher than INZ (CH) + β depending on the pressing force applied to the string 9, as indicated by “PE” in FIG. Therefore, when the output level of the photodiode 15 continues to exceed INZ (CH) + β for a predetermined time γ or more, it can be detected that the string 19 is pressed.

FIG. 6 is a block diagram showing the circuit configuration of the electronic guitar according to this embodiment. In the CPU 21, signals from the photodiodes 15 provided in each of the six photosensors 13 are A / A. While being input via the D converter 22, operation information is input from the fret switch unit 6 and the body switch unit 17. ROM23
In addition to the programs necessary for all controls executed in this electronic guitar, the tone color data corresponding to the tone color number set by the tone color setting switch 19 is stored. The CPU 21 operates according to these input signals, programs, etc., and data stored in the RAM 24, etc., and controls the tone generator 25 and other units.

The sound source section 25 has six sounding channels corresponding to the six strings 9, and generates musical tone waveform data of a designated tone color and pitch for each sounding channel in accordance with a sounding instruction from the CPU 21. Then, the filter unit 26 processes the musical tone waveform data generated by the sound source unit 25 according to the filter coefficient set by the filter switch 20. The musical tone waveform data processed by the filter unit 26 is converted into an analog musical tone waveform by the D / A converter 27 and is given to the amplification unit 28. The amplifier 28 amplifies the musical tone waveform according to the volume set by the volume switch 18, and the speaker 29 is driven by the amplified musical tone waveform, so that the sound is emitted to the outside through the slit portion 16. Is configured.

Next, the operation of this embodiment having the above configuration will be described with reference to the flowcharts shown in FIG. The reference numerals used in each flow chart indicate various registers shown in FIG. 7 and the following. CH: The string numbers "0" to "5" corresponding to the first to sixth strings are stored. CH2: In the timer interrupt processing, the string number "0" ~
Store “5”. CH3: In the fret switch-off interruption process, the string numbers "0" to "5" are stored. DATA: The latest A / D conversion value of the photodiode output is stored. INZ (0) to (5): Store the average value of the photodiode output when the string is stationary. MAX (0) to (5): Shows the maximum and minimum values of the photodiode output at the start of string vibration. CNT (0) to (5): The number of times that the output value of the photodiode exceeds INZ (CH) ± α shown in FIG. 5 due to string vibration is stored. TIM (0) to (5): Indicates a timer count value. ON (0) to (5): "1" indicates that sound is being generated, and "0" indicates that sound is being stopped. PLS (0) to (5): “1” indicates that it is larger than INZ (CH) + α, and “0” indicates that it is smaller than INZ (CH) −α. In the above, (0) to (5) indicate that they are registers corresponding to the string numbers "0" to "5" in parentheses.

That is, when the power is turned on, the CPU 21 starts its operation according to the main flow shown in FIG.
First, the initial process (SA1) is executed. This initial processing (S
A1) is performed according to the flow shown in FIG. 9, and registers ON (0) to ON (5) and CNT (0) to (5) are reset (SB1, SB2) and INZ (0) to.
In (5), the average value of the photodiode output when the corresponding strings are stationary is stored (SB3). After that,
Set "0" to CH and return (SB4). Therefore, at the end of this initial processing, "0" is set to CH.
Is set.

Then, in the main flow of FIG. 8, following this initial processing (SA1), body switch processing (S
A2) is executed to select a tone color waveform according to the operation of the tone color setting switch 19 provided in the body switch section 17, and to set a filter coefficient according to the operation of the filter switch 20. Next, fret switch processing (SA
3) is executed to scan the fret switch section 6 to detect the switch turned on by the pressing operation to determine the pitch to be generated at the time of striking the corresponding string, and the switch turned off. Detecting and muting the corresponding tone.

Subsequently, after string processing (SA4) is executed, it is judged whether or not "0" is set in the register ON (CH) designated by the value of CH (SA5),
If ON (CH) = 0 and no sound is being generated, vibration detection processing is executed (SA6). If ON (CH) = 1 and sound is being generated, string contact detection processing is executed. (S
A6). After that, it is determined whether or not CH has become “5”. If CH ≠ 5, CH is incremented (SA10) and the process returns to SA3. If CH = 5, CH Set the initial value "0" to (SA
9) Return to SA2. Therefore, CH is the initial value "0"
From the maximum value to "5", the value indicates the string number at which the string process (SA4), the string vibration detection process (SA6), and the string contact detection process (SA7) are to be performed at that time. Therefore, while the power is on, the processing is performed according to this main flow, so that the fret switch processing, the string processing, the vibration detection processing, and the string contact detection processing are sequentially performed for each of the first to sixth strings. Each process will be repeated.

Further, the CPU 21 executes the timer interrupt process shown in FIG. 10 at the timing synchronized with the internally generated clock of a predetermined cycle, and first, the register CH2 is set to "0".
Is stored (SC1). Next, the value of the timer register TIM (CH2) indicated by the value of CH2 is counted up (SC2). Then, it is determined whether or not CH2 becomes “5” (SC3), and if CH2 ≠ 5, the process returns. If CH2 = 5, the value of CH2 is incremented (SC4) to SC2. Return. Therefore, this timer interrupt process causes the timer registers TIM (0) to TIM (5) corresponding to the first to sixth strings to be counted up at regular time intervals.

On the other hand, the string processing (SA4) in the main flow is performed according to the flow shown in FIG.
The output of the photodiode 15 corresponding to the value of the register CH that sequentially stores the string numbers "0" to "5" is A / D converted (SD1) and stored in the register DATA (SD.
2). Therefore, by this string processing, the register DAT
In A, the latest A / D conversion value of the photodiode 15 corresponding to the string number indicated by CH is stored while being sequentially updated.

The main flow string vibration detection processing (S
A6) is executed according to the series of flows shown in FIGS. First, it is determined whether or not the value of the register CNT (CH) designated by the value of CH is "0" (SE1). Here, as described above with reference to FIG. 5, the CNT (CH) has the output of the corresponding photodiode 15 INZ (C
H) A register indicating the number of times exceeding ± α. At this time, if CNT (CH) = 0 and the number of times of exceeding is “0”, the latest output value of the photodiode stored in the register DATA is INZ (CH).
It is determined whether ± α is exceeded on the plus side (SE2) or on the minus side (SE4). And DA
If TA> INZ (CH) + α and it exceeds the plus side, PLS (CH) is set (SE3) and DAT is set.
When A <INZ (CH) -α and exceeds the negative side, PLS (CH) is reset (SE5).

Then, in order to measure the time from the time when the plus side or the minus side is exceeded, the register TIM
Reset (CH) (SE6) and INZ
Register CNT (C indicating the number of times (CH) ± α is exceeded
"1" is set to H) (SE7). Then, subtract the average output value of the photodiode stored in INZ (CH) during string rest from the photodiode output value stored in the register DATA, and set the absolute value of that value to MAX (CH). After storing (SE8), it returns.

On the other hand, as a result of the discrimination in SE1, CNT (C
H) ≠ 0 and the number of times is stored in the register CNT (CH), the process proceeds to the flow of FIG.
Does the value of ATA exceed INZ (CH) ± α on the plus side (SE9) or on the minus side (SE1)?
2) is detected. Then, as a result of the determination in SE9, DA
If TA> INZ (CH) + α and it exceeds the plus side, it is determined whether or not PLS (CH) = 0 at this time (SE10). If the state of PLS (CH) = 1, it means that the state of exceeding the plus side continues, and in this case, the process proceeds from SE10 to SE23.

As a result of the determination in SE12, DATA
<SE2 even when INZ (CH) -α is not used
3. If DATA <INZ (CH) -α and it exceeds the negative side, PLS (CH) at this time
It is determined whether or not the state is = 1 (SE13). PL
If it is in the state of S (CH) = 0, it means that the state of exceeding the minus side is continuing, and in this case also, it proceeds to SE23.

Then, in this SE23, TIM (C
(H) determines whether the timer count value exceeds a predetermined value γ. If it exceeds the predetermined value γ, it is considered that the string is not vibrating, and CNT (CH) is reset to 0. And return. That is, DATA> INZ (CH) +
When the state where neither α nor DATA <INZ (CH) -α is satisfied (SE12 is NO) continues for a predetermined time γ or more, it can be considered that the string 9 is stationary.
In addition, DATA> INZ (CH) + α or DATA <I
NZ (CH) -α state (SE10 or SE13 is N
3) is continued for a predetermined time γ of O), for example, as shown in FIG.
As indicated by PS, there is a case where the output level of the photodiode 15 is changed due to the pressing of the string at the start of the string firing, and the string vibration has not started yet at this point. Therefore, in this case, reset CNT (CH) (SE
24) Return.

However, as a result of the determination of SE23, TIM
If (CH)> γ does not hold, register DAT
From the photodiode output stored in A, INZ
The output average value of the photodiode stored in (CH) when the string is stationary is subtracted, and the value of the register DATA is updated by the absolute value of the value (SA20). Furthermore, this updated DATA value is
It is determined whether it is larger than the value of X (CH), and DAT
If A> MAX (CH), the value of MAX (CH) is rewritten to the value of DATA (SE22). Therefore, MAX (CH) has an I when INZ (CH) ± α is most greatly exceeded in the plus or minus direction.
The absolute value of the difference from NZ (CH) will be stored while being sequentially updated.

On the other hand, when determining SE10, PLS (C
If H) = 0, it means that the output of the photodiode 15 exceeds the minus side and then exceeds the plus side, and the string 9 starts to vibrate. Therefore, in this case, after the PLS (CH) reset in SE5 is set (SE11), it is determined whether CNT (CH) is "2" (SE15). Also, SE1
When PLS (CH) = 1 in the determination of 3, it means that the output of the photodiode 15 exceeds the positive side and then the negative side. Similarly, the string 9 starts to vibrate. There is. Therefore, after resetting the PLS (CH) set in SE5 (SE14), C
It is determined whether NT (CH) is "2" (SE15). And in this SE15, CNT
If the value of (CH) is not “2”, that is, if CNT (CH) = 1 still, TIM (CH) is set to 0.
After reset (SE18), CNT (CH) is "2"
Is set (SE19). After that, the above-mentioned SE
The process from 20 to SE22 is performed and the process returns.

Then, in this way, in SE19, CNT (C
When DATA> INZ (CH) + α with PLS (CH) = 0 after H) is set to “2”, SE9 → SE10 → SE11 → SE15 → SE16
Then, the pronunciation process is executed and PLS (CH) = 1
If DATA> INZ (CH) -α in the state of, SE9 → SE12 → SE13 → SE14 → SE15
→ Proceed to SE16 to execute the pronunciation process. Therefore,
The string 9 starts to vibrate due to the striking string, and the output of the photodiode 15 is INZ (CH) ± α as illustrated in FIG.
Sounding processing (SE16) at the time when the total exceeds three times (of which ± is opposite to the first, third and second times).
Will be executed.

In this tone generation processing, the CPU 21 reads from the ROM 23 the waveform data indicated by the tone color number specified by the operation of the body switch section 17, and the pitch specified by the operation of the fret switch section 6 is MAX. INZ (CH) ± stored in (CH)
The sound source unit 25 is instructed to generate the musical tone waveform data of the volume corresponding to the absolute value of the difference from INZ (CH) when α is most exceeded. In accordance with this instruction, the sound source section 25 generates and outputs the specified musical tone waveform data in the designated sounding channel, and the filter section 26 filters the musical tone waveform data according to the coefficient set by the filter switch 20. To do.

The filtered musical tone waveform data is converted into an analog musical tone waveform by the D / A converter 27, and the amplifier 28 amplifies the musical tone waveform according to the volume set by the volume switch 18, and this amplification is performed. The speaker 29 operates according to the generated musical tone waveform. This allows
From the speaker 29, the tone volume switch 1 has a volume corresponding to the strength of the plucked string within the set volume range.
A musical tone having a tone color designated by the operation 9 and a pitch designated by the operation of the fret switch section 6 starts to be generated.

Further, in the main flow of FIG. 8, the string contact detection processing (SA7) is executed according to the flow shown in FIG. First, the photodiode 1 corresponding to CH
The value of DATA storing the A / D conversion value of 5 is INZ
Whether (CH) ± β is exceeded on the plus side (SF1) or on the minus side (SF3) is detected. Then, as a result of the determination in SF1, DATA> INZ (CH)
If it is + β and exceeds the plus side, it is determined at this time whether or not PLS (CH) = 1.
F2). If it is not in the state of PLS (CH) = 1, it can be assumed that the state of DATA> INZ (CH) + β has occurred at this point, so PLS (CH) is changed to indicate that this state has occurred. After setting (SF10),
TIM (CH) is reset (SF11).

However, as a result of the discrimination in SF2, PLS
If (CH) = 1, DATA> INZ (CH) + β
The state of has continued from before. Therefore, SF2 to S
Proceed to F5 to determine whether the value of TIM (CH), which measures the duration of DATA> INZ (CH) + β, is γ or more, and mute when TIM (CH)> γ The process is executed (SF6). This silence processing (SF6)
As a result, the sound source unit 25 causes the envelope E as shown in FIG.
Is released at a rate R1 larger than that in the normal natural decay, whereby the corresponding musical sound generated from the speaker 29 is rapidly attenuated and muted. Continue to O
Set “0” to N (CH) (SF7),
CNT used in the above-mentioned string vibration detection processing (FIGS. 12 and 13)
Reset (CH) and return.

As a result of the discrimination in SF3, DATA <
In the case of INZ (CH) -β and the output of the photodiode 15 exceeds the negative side, at this time PLS
It is determined whether or not (CH) = 0 (SF
4). If it is not in the state of PLS (CH) = 0, it can be assumed that the state of DATA <INZ (CH) -β has occurred at this point. Therefore, in order to show that this state has occurred, PLS (CH) After resetting (SF9), T
IM (CH) is reset (SF11).

However, as a result of the discrimination in SF4, PLS
If (CH) = 0, DATA <INZ (CH) -β
The state of has continued from before, and in this case, since the string 9 is pressed diagonally downward without being pressed vertically downward,
It can be assumed that the state of DATA <INZ (CH) -β continues. Therefore, also in this case, it can be considered that the string pressing is based on the player's intention to mute. Therefore, proceeding from SF4 to SF5, DATA <IN
TIM (C that measures the duration of Z (CH) -β
It is determined whether the value of (H) is γ or more, and TIM (C
When H)> γ, the muffling process is executed in the same manner as described above (SF6), and the envelope E is set to the released state. Thereafter, as described above, "0" is set to ON (CH) (SF7), the CNT (CH) used in the above-described string vibration detection processing (FIGS. 12 and 13) is reset, and the process returns.

As described in the fret switch processing (SA3) of the main flow, the finger is released from the pressed fret switch section 6 without pressing the plucked string 9 with the finger. Even when the fret switch corresponding to the string is turned off, the mute processing is executed. However, in the muffling process in this case, as shown in FIG. 4, the envelope E is set to the above-described rate R1 (FIG. 3).
Release rate is set at a smaller rate R2. Therefore, when the fret switch is turned off, unlike the case where the vibrating string is pressed with a finger, the generated musical tone is gradually attenuated. Further, when the mute processing accompanying the turning off of the fret switch is executed, the fret switch off interruption processing shown in the flow of FIG.
The number (0 to 5) corresponding to the string to be silenced is stored in H3 (SG1). Subsequently, "0" is stored in the register ON (CH3) indicated by the value of CH3 (SG2), which indicates that the string muted in the sound source unit 25 is in the non-sounding state.

Further, in this embodiment, the case where the present invention is applied to the electronic guitar is shown, but it is needless to say that the present invention can be applied to other electronic string instruments such as an electronic violin.

[0039]

As described above, according to the present invention, when the signal outside the predetermined level range is continuously output from the string vibration detecting means which outputs the signal of the level corresponding to the distance to the string, the mute instruction is issued. It is configured to perform. Therefore, a touch detection circuit is provided separately from the string vibration detection means for detecting the vibration of the strings, and the configuration is simplified as compared with the conventional electronic stringed instrument that gives a mute instruction in response to a touch on the strings. By touching the strings while reducing the number of points and assembling man-hours, it is possible to perform the same playing method as an acoustic guitar in which the generated musical sound is rapidly attenuated.

Further, the string vibration detecting device is provided with a reflecting member provided on the string and having a width wider than the diameter of the string, a light source for irradiating light toward the surface of the reflecting member, and the circle which is irradiated by the light source. A general-purpose photo sensor can be used as the string vibration detecting means by configuring the light receiving means for receiving the light reflected on the surface of the columnar member, which further reduces the number of assembly steps and the cost. In addition to being possible, because the reflection member reflects the light rays more reliably,
It becomes possible to detect the displacement of the string more favorably.

[Brief description of drawings]

FIG. 1 is a plan view showing an appearance of an electronic guitar according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a waveform diagram showing an example of the output state of the photodiode including when strung and when the string is pressed.

FIG. 4 is a waveform chart showing an example of an output state of a photodiode during and after striking a string.

FIG. 5 is a waveform diagram showing the start of sound generation in relation to the output state of the photodiode.

FIG. 6 is a block configuration diagram of an electronic guitar according to the present embodiment.

FIG. 7 is an explanatory diagram showing a register used in this embodiment.

FIG. 8 is a flowchart showing a main flow.

FIG. 9 is a flowchart showing the contents of initial processing.

FIG. 10 is a flowchart showing the contents of timer interrupt processing.

FIG. 11 is a flowchart showing the content of string processing.

FIG. 12 is a flowchart showing a part of the content of vibration detection processing.

FIG. 13 is a flowchart following FIG.

FIG. 14 is a flowchart showing the content of string contact detection processing.

FIG. 15 is a flowchart showing the contents of a mute end interrupt process.

[Explanation of symbols]

 1 Guitar Main Body 6 Fret Switch Section 9 String 11 Cylindrical Member 11a Circumferential Surface 13 Photo Sensor 14 Light Source Section 15 Photodiode 21 CPU 23 ROM 24 RAM 25 Sound Source Section

Claims (4)

[Claims] 1. A string vibration detecting means for outputting a signal having a level according to the distance to the string, and an instruction to generate a musical tone when the output signal level of the string vibration detecting means changes in accordance with the vibration of the string. An electronic string instrument, comprising: a sound generation instruction means for performing the sound generation; and a mute instruction means for instructing the mute of the musical sound when a signal outside the predetermined level range is continuously output from the string vibration detection means. 2. A pitch designating means for designating a pitch, a string vibration detecting means for outputting a signal of a level corresponding to a distance to a string, and an output signal of the string vibration detecting means in accordance with the vibration of the string. When the level changes, a tone generation instruction means for instructing the generation of a tone having a pitch designated by the pitch designation means and a signal outside the predetermined level range are continuously output from the string vibration detection means. A mute instructing means for instructing the mute of the musical sound when the electronic string instrument is played. 3. A reflecting member provided on a string and having a width wider than the diameter of the string, a light source that irradiates light toward the surface of the reflecting member, and a light source that is irradiated by the light source and reflected on the surface of the reflecting member. A string vibration detecting device comprising: a light receiving unit that receives light and outputs a signal according to a light receiving state. 4. The reflecting member has a cylindrical shape, the light source emits light toward a peripheral surface of the reflecting member, and the light receiving unit outputs a signal according to an amount of received light. The string vibration detection device according to claim 3.