Instrument signal output device, and method for controlling an instrument signal in the instrument signal output device

Abstract

To enable connection matching with electronic musical instruments to be correctly performed without relying on specifications of the electronic musical instrument regarding a musical instrument signal output device including an expression pedal, and a musical instrument signal control method in the musical instrument signal output device.SOLUTION: A playing operation signal according to a playing operation of a player is input to a microcomputer 111 via a volume variable resistor 124. A PWM signal generation unit 113 within the microcomputer 111 is configured to: generate a PWM signal 130 having a pulse width modulated at a modulation degree in accordance with a value of the playing operation signal; further generate a musical instrument signal 123 from the PWM signal 130; and supply the musical instrument signal to an electronic musical instrument via a first switch 114 or second switch 115.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a musical instrument signal output device such as an expression pedal, and a method for controlling a musical instrument signal in a musical instrument signal output device. [Background technology]

[0002] There are known musical instrument signal output devices such as expression pedals that are connected to electronic musical instruments as musical instrument performance controls, but because the wiring method of the connection plug and the internal structure of the pedal and electronic musical instrument body differ depending on the manufacturer, users have to purchase pedals that are compatible with their electronic musical instruments. Specifically, for example, a stereo standard phone plug is generally used for the connection plug, but there are two types: a first type in which the power supply, signal line, and ground are wired in the order of tip, ring, and sleeve, and a second type in which the signal line, power supply, and ground are wired. When a pedal with an incompatible polarity is connected to each electronic musical instrument, it does not operate normally, and in some cases the electronic musical instrument or pedal may even break down.

[0003] To address this problem, a first prior art technology is known that includes a product equipped with a polarity changeover switch that enables a proper connection between an electronic musical instrument and a pedal by reversing the polarity (for example, Non-Patent Document 1).

[0004] As a second conventional technique, an adapter cable capable of reversing polarity by connecting to a standard stereo phone plug is known (for example, Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] "M-AUDIO Expression Pedal EX-P", Internet search on December 10, 2020<URL:http: / / m-audio.jp / ex-p / > [Non-Patent Document 2] "TRS conversion adapter", Internet search on December 10, 2020<URL:https: / / beatbars.com / ja / trs-extension-reversed.html> Summary of the Invention [Problem to be solved by the invention]

[0006] There are correspondences and non-compatibility between electronic musical instruments and expression pedals that are not obvious from the outside. In addition, the volume resistance value inside the pedal is generally 10kΩ to 50kΩ, but there are also other resistance values. However, simply reversing the polarity as in the above conventional technology causes the volume resistance value on the pedal side and the input impedance on the electronic musical instrument side to not match, narrowing the input range of the actual musical instrument signal relative to the range of motion of the pedal, making it impossible to supply the musical instrument signal to the electronic musical instrument as the performer intended, resulting in a narrow range of performance effects.

[0007] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to enable correct connection matching with an electronic musical instrument regardless of the specifications of the electronic musical instrument. [Means for solving the problem]

[0008] According to one embodiment of the present invention, there is provided a signal output device for a musical instrument, comprising: an operation signal acquisition unit that acquires an operation signal corresponding to an operation by a player; The above generating a pulse width modulated signal whose pulse width is modulated at a modulation factor corresponding to the value of the operation signal; The above a pulse width modulated signal generating section for supplying a pulse width modulated signal to an electronic musical instrument as a musical instrument signal; a level shifter for converting a voltage level of the pulse width modulated signal; a first terminal and a second terminal; a first switch connected to the first terminal and having a first switch terminal and a second switch terminal; a second switch connected to the second terminal and having a first switch terminal and a second switch terminal; 3Sand a control unit, wherein the control unit controls the first switch, the second switch, and the third switch so that, when a power supply voltage is input from the first terminal via the first switch, the control unit inputs the power supply voltage to the level shifter via the first switch terminal and the third switch of the first switch, and outputs the pulse width modulation signal converted by the level shifter to the second terminal via the second switch terminal of the second switch, and when a power supply voltage is input from the second terminal via the second switch, the control unit controls the first switch, the second switch, and the third switch so that the control unit inputs the power supply voltage to the level shifter via the first switch terminal and the third switch of the second switch, and outputs the pulse width modulation signal converted by the level shifter to the first terminal via the second switch terminal of the first switch. Effect of the Invention

[0009] According to the present invention, connection matching with an electronic musical instrument can be performed correctly regardless of the specifications of the electronic musical instrument. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram of an expression pedal device according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing a state in which a standard stereo phone plug is used in the embodiment. [Diagram 3] 4 is a flowchart illustrating an example of a control process according to the embodiment. [Figure 4] 5A to 5C are diagrams illustrating examples of operational waveforms of musical instrument signals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The embodiment of the present invention described below is an expression pedal device that can be connected to an electronic musical instrument by cable and allows the performer to control the volume by pedal operation. Figure 1 is a block diagram of an expression pedal device 100 according to the embodiment.

[0012] The appearance of the expression pedal device 100 is such that a pedal section 102 is attached to a pedal case section 101 so as to be rotatable about a pedal rotation shaft 103. By stepping on the pedal section 102 with the foot, the performer can control the sound volume of an electronic musical instrument (not shown) according to the degree to which the performer steps on the pedal section 102. For this purpose, the expression pedal device 100 supplies the electronic musical instrument with a musical instrument signal according to the degree to which the performer steps on the pedal section 102. Note that the parameter controlled by the performer stepping on the pedal section 102 is not limited to the sound volume, and may be, for example, a sound effect such as wah-wah or distortion. An LED display section 104 for displaying the operation state of the pedal is provided on the upper part of the pedal case section 101. An instrument connection jack section 105 for connecting to an electronic musical instrument with a stereo standard phone plug cable is provided on the side of the pedal case section 101.

[0013] A control system 110 is built into the pedal case 101. In the control system 110, a microcomputer 111 that operates as a discrimination unit and a control unit controls the overall operation of the expression pedal device 100. The microcomputer 111 has an A / D conversion unit 112 and a PWM signal generation unit 113 built in.

[0014] An expression pedal connection jack of an electronic musical instrument (not shown) and the musical instrument connection jack section 105 of the expression pedal device 100 are connected by a stereo standard phone plug cable. The stereo standard phone plug of this cable is a plug having three contacts, a TIP contact 201, a RING contact 202, and a SLEEVE contact 203, as shown, for example, as 210 in FIG. 2. Each contact is insulated by an insulating material. The TIP contact 201, the RING contact 202, and the SLEEVE contact 203 are connected to the internal circuitry of the electronic musical instrument via a TIP wire 204, a RING wire 205, and a SLEEVE wire 206, respectively.

[0015] When a standard stereo phone plug is inserted into instrument connection jack 105 of FIG. 1, TIP contact 201, RING contact 202, and SLEEVE contact 203 of the standard stereo phone plug are connected to TIP terminal 125, RING terminal 126, and SLEEVE terminal 127 in instrument connection jack 105, respectively.

[0016] A TIP terminal 125 of the musical instrument connection jack unit 105 is connected to a first switch (indicated as “first SW” in the drawing) 114, which is a part of the switch unit. The first switch 114 is an electronic switch that has a first switch terminal t1 and a second switch terminal t2 that can be switched, and can be controlled by the microcomputer 111.

[0017] A first switch terminal t1 of the first switch 114 is connected to a terminal AIN1 of the A / D conversion unit 112 in the microcomputer 111 via a level shifter 119. A second terminal of the first switch terminal t1 is connected to a first terminal of a resistor 117 connected to a sleeve terminal 127 that supplies a ground level from the electronic musical instrument. The level shifter 119 receives internal power from a battery 128 via a power switch 129 at a first power supply terminal (not shown), and a second power supply terminal (not shown) is connected to the sleeve terminal 127 that supplies a ground level from the electronic musical instrument. When a voltage signal is input via the first switch terminal t1 of the first switch 114, the level shifter 119 converts the voltage value of the portion connected to the resistor 117 into a voltage value that can be monitored by the A / D conversion unit 112.

[0018] A second switch terminal t2 of the first switch 114 is connected to an LPF (low pass filter) 122, which will be described later, that outputs a signal 123 for a musical instrument.

[0019] The RING terminal 126 of the musical instrument connection jack unit 105 is connected to a second switch (indicated as "second SW" in the drawing) 115, which is a part of the switch unit. The second switch 115 is an electronic switch that has a first switch terminal t1 and a second switch terminal t2 that can be switched, and can be controlled by the microcomputer 111.

[0020] A first switch terminal t1 of the second switch 115 is connected to a terminal AIN2 of the A / D conversion unit 112 in the microcomputer 111 via a level shifter 120. A second terminal of the first switch terminal t1 is connected to a first terminal of a resistor 118 connected to a sleeve terminal 127 that supplies a ground level from the electronic musical instrument. The level shifter 120 receives internal power from a battery 128 via a power switch 129 at a first power supply terminal (not shown), and a second power supply terminal (not shown) is connected to the sleeve terminal 127 that supplies a ground level from the electronic musical instrument. When a voltage signal is input via the first switch terminal t1 of the second switch 115, the level shifter 120 converts the voltage value at the portion connected to the resistor 118 into a voltage value that can be monitored by the A / D conversion unit 112.

[0021] A second switch terminal t2 of the second switch 115 is connected to an LPF 122, which will be described later, that outputs a signal 123 for a musical instrument.

[0022] A first switch terminal t1 of a third switch (indicated as "third SW" in the drawing) 116, which is a part of a switch section for inputting a power supply voltage from an electronic musical instrument, is connected to a first switch terminal t1 of the first switch 114, a second switch terminal t2 of the third switch 116 is connected to a first switch terminal t1 of the second switch 115, and a third switch terminal t3 of the third switch 116 is connected to a power switch 129 to which a battery 128 is connected. The third switch 116 is an electronic switch that can be controlled by the microcomputer 111. The third switch 116 supplies the power supply voltage inputted via the first switch terminal t1 of the third switch 116, the second switch terminal t2 of the third switch 116, or the third switch terminal t3 of the third switch 116 to a first power supply terminal (not shown) of the level shifter 121. A second power supply terminal (not shown) of the level shifter 121 is connected to a SLEEVE terminal 127 that supplies a ground level from the electronic musical instrument side. The level shifter 121 converts the voltage level of a PWM signal 130 output by a PWM (pulse width modulation) signal generating section 113 in a microcomputer 111 (described later) into a voltage level that can be processed on the electronic musical instrument side.

[0023] The volume variable resistor 124 has a first fixed terminal to which the power supply voltage supplied from the third switch 116 is input, and a second fixed terminal to which the SLEEVE terminal 127 is connected. The variable terminal of the volume variable resistor 124 slides variably when the performer depresses the pedal section 102 of the expression pedal device 100, and the voltage value detected from the variable terminal is detected at the terminal AIN0 of the A / D conversion section 112 in the microcomputer 111 as a variable voltage value of a digital performance operation signal.

[0024] The microcomputer 111 detects the variable voltage value of the volume variable resistor 124 via the terminal AIN0 of the A / D conversion section 112, and causes the PWM signal generating section 113 to generate a PWM signal 130 that has been pulse-width modulated in accordance with the variable voltage value.

[0025] This PWM signal 130 is voltage converted by the level shifter 121, and then smoothed by the LPF 122. The output of the LPF 122 is output as an instrument signal 123 from the TIP terminal 125 or the RING terminal 126 to the electronic musical instrument via the first switch terminal t1 of the first switch 114 or the second switch 115.

[0026] In addition, an LED display unit 104 is connected to the microcomputer 111. The microcomputer 111 causes the LED display unit 104 to digitally display the operation state of the expression pedal device 100 by the performer (for example, the amount of depression of the pedal unit 102), error display (described later), and the like.

[0027] The operation of the expression pedal device 100 having the configuration shown in Fig. 1 and the control system 110 built therein will be described with reference to the flowchart of Fig. 3. Fig. 3 is a flowchart showing an example of control processing executed by the microcomputer 111 of Fig. 1. This control processing is processing in which the microcomputer 111 executes a control program stored in an internal memory (not shown).

[0028] When the power switch 129 of FIG. 1 is turned on, the microcomputer 111 first executes an initialization process (step S301 of FIG. 3). In this initialization process, the microcomputer 111 causes the first switch (indicated as "first SW" in the figure) 114 of FIG. 1 to select the first switch terminal t1, the second switch (indicated as "second SW" in the figure) 115 of FIG. 1 to select the first switch terminal t1, and the third switch (indicated as "third SW" in the figure) 116 of FIG. 1 to select the third switch terminal t3. As a result, the microcomputer 111 enters a state of waiting for a stereo standard phone plug cable to be connected to the instrument connection jack 105 from an electronic musical instrument (not shown).

[0029] In a standby state for connection of a standard stereo phone plug cable, the signal level of the TIP terminal 125 of the instrument connection jack 105 is detected as a digital value at the terminal AIN1 of the A / D conversion unit 112 in the microcomputer 111, which is also powered by the battery 128, via the first switch terminal t1 of the first switch 114 through the level shifter 119 powered by the battery 128 inside the pedal.

[0030] In addition, the signal level of the RING terminal 126 of the instrument connection jack section 105 is detected as a digital value at the terminal AIN2 of the A / D conversion section 112 in the microcontroller 111 operated by the battery 128 from the first switch terminal t1 of the second switch 115 via the level shifter 120 operated by the battery 128.

[0031] Furthermore, the level shifter 121 that converts the voltage value of the PWM signal 130 operates on the power supply voltage from the battery 128 supplied via the third switch terminal t3 of the third switch 116 when the power is first turned on.

[0032] In this state, the microcontroller 111 determines whether the voltage value detected by the terminal AIN1 of the internal A / D conversion unit 112 has become a logically high level and the voltage value detected by the terminal AIN2 of the internal A / D conversion unit 112 has become a logically low level (step S302 in FIG. 3).

[0033] If the determination in step S302 is YES, the microcomputer 111 causes the first switch 114 in Fig. 1 to select the first switch terminal t1, the second switch 115 in Fig. 1 to select the second switch terminal t2, and the third switch 116 in Fig. 1 to select the first switch terminal t1. Then, the microcomputer 111 turns on the internal PWM signal generating unit 113 to start the operation of the expression pedal device 100 (step S303 in Fig. 3).

[0034] As described above, when the determination in step S302 becomes YES, the microcomputer 111 recognizes that the stereo standard phone plug cable connected to the electronic musical instrument is connected to the musical instrument connection jack unit 105, and determines that the electrical state is the type 1 electrical state shown in Fig. 2(a). As shown in Fig. 2(a), in the type 1 electrical state, on the electronic musical instrument side, a power source 207 inside the electronic musical instrument is connected to a tip contact 201 of the stereo standard phone plug and a tip line 204 connected to the tip contact 201. Also, a signal circuit 208 for detecting a musical instrument signal from the expression pedal device 100 side is connected to a ring contact 202 of the stereo standard phone plug and a ring line 205 connected to the ring contact 202. Furthermore, a ground level 209 is connected to a sleeve contact 203 of the stereo standard phone plug and a sleeve line 206 connected to the sleeve contact 203.

[0035] The microcomputer 111 executes the control of step S303 in FIG. 3 to start the operation of the expression pedal device 100, thereby causing the control system 110 in FIG. 1 to execute the following control operations.

[0036] First, in the power supply state of Type 1 in FIG. 2(a), the power supply voltage from the power supply 207 of the electronic musical instrument, which is input from the TIP line 204 and TIP contact 201 of the stereo standard phone plug connected to the electronic musical instrument via the TIP terminal 125 of the musical instrument connection jack section 105, is supplied to the level shifter 121 from the first switch terminal t1 of the first switch 114 via the first switch terminal t1 of the third switch 116.

[0037] 2(a), the instrument signal 123 output from the LPF 122 is output from the second switch terminal t2 of the second switch 115 via the RING terminal 126 of the instrument connection jack section 105. As a result, the instrument signal 123 is supplied from the RING contact 202 of the standard stereo phone plug connected to the electronic instrument via the RING line 205 to a signal circuit 208 in the electronic instrument.

[0038] In this way, simply by connecting an electronic musical instrument having the Type 1 power state of FIG. 2(a) to the instrument connection jack 105 of the expression pedal device 100 of FIG. 1 by a standard stereo phone plug cable, power can be automatically and correctly supplied from the electronic musical instrument to the expression pedal device 100, and the instrument signal 123 can be automatically and correctly supplied from the expression pedal device 100 to the electronic musical instrument.

[0039] If the determination in step S302 is NO, the microcontroller 111 then determines whether the voltage value detected by the terminal AIN1 of the internal A / D conversion unit 112 is a logically low level and whether the voltage value detected by the terminal AIN2 of the internal A / D conversion unit 112 is a logically high level (step S304 in FIG. 3).

[0040] If the determination in step S304 is YES, the microcomputer 111 causes the first switch 114 in Fig. 1 to select the second switch terminal t2, the second switch 115 in Fig. 1 to select the first switch terminal t1, and the third switch 116 in Fig. 1 to select the second switch terminal t2. Then, the microcomputer 111 turns on the internal PWM signal generating unit 113 to start the operation of the expression pedal device 100 (step S305 in Fig. 3).

[0041] As described above, when the determination in step S304 becomes YES, the microcomputer 111 recognizes that the stereo standard phone plug cable connected to the electronic musical instrument is connected to the musical instrument connection jack unit 105, and determines that the electrical state is the type 2 electrical state shown in Fig. 2(b). As shown in Fig. 2(b), in the type 2 electrical state, on the electronic musical instrument side, a signal circuit 208 for detecting a musical instrument signal from the expression pedal device 100 side is connected to the TIP contact 201 of the stereo standard phone plug and the TIP line 204 connected to the TIP contact 201. In addition, a power source 207 inside the electronic musical instrument is connected to the RING contact 202 of the stereo standard phone plug and the RING line 205 connected to the RING contact 202. Furthermore, a ground level 209 is connected to the SLEEVE contact 203 of the stereo standard phone plug and the SLEEVE line 206 connected to the SLEEVE contact 203.

[0042] The microcomputer 111 executes the control of step S305 in FIG. 3 to start the operation of the expression pedal device 100, thereby causing the control system 110 in FIG. 1 to execute the following control operations.

[0043] First, in the type 2 power state of FIG. 2(b), the power supply voltage from the power supply 207 of the electronic instrument, which is input from the RING line 205 and RING contact 202 of the standard stereo phone plug connected to the electronic instrument via the RING terminal 126 of the instrument connection jack section 105, is supplied to the level shifter 121 from the first switch terminal t1 of the second switch 115 via the second switch terminal t2 of the third switch 116.

[0044] 2(b), the instrument signal 123 output from the LPF 122 is output from the second switch terminal t2 of the first switch 114 via the TIP terminal 125 of the instrument connection jack section 105. As a result, the instrument signal 123 is supplied to a signal circuit 208 in the electronic instrument via a TIP line 204 from a TIP contact 201 of a standard stereo phone plug connected to the electronic instrument.

[0045] In this way, simply by connecting an electronic musical instrument having the Type 2 power state of FIG. 2(b) to the instrument connection jack 105 of the expression pedal device 100 of FIG. 1 by a standard stereo phone plug cable, power can be automatically and correctly supplied from the electronic musical instrument to the expression pedal device 100, and the instrument signal 123 can be automatically and correctly supplied from the expression pedal device 100 to the electronic musical instrument.

[0046] If the determination in step S304 is NO, the microcontroller 111 further determines whether the voltage value detected by the terminal AIN1 of the internal A / D conversion unit 112 and the voltage value detected by the terminal AIN2 are both at a logically high level (step S306 in FIG. 3).

[0047] If the determination in step S306 is YES, the microcomputer 111 recognizes that a stereo standard phone plug cable connected to an electronic musical instrument is connected to the musical instrument connection jack 105, and recognizes that the connection is abnormal. As a result, the microcomputer 111 determines that there is an error in the connection with the electronic musical instrument, and causes the LED display 104 in Fig. 1 to display an error state (step S307 in Fig. 3).

[0048] If the determination in step S306 is also NO, the microcomputer 111 recognizes that no cable has yet been connected to the instrument connection jack section 105, and leaves the states of the first switch 114, the second switch 115, and the third switch 116 of the control system 110 in FIG. 1 unchanged from their initial states, and returns to the determination process in step S302 in FIG. 3 to continue the connection waiting state.

[0049] FIG. 4 is an operation waveform diagram showing the effect of using the PWM signal 130 of FIG. 1 as the instrument signal 123. As described above, in this embodiment, the voltage division value by the volume variable resistor used in a normal expression pedal is not output as it is, but the volume variable voltage value is output as a voltage value from the A / D conversion unit 112 in the microcomputer 111 via the PWM signal generation unit 113. This makes it possible to solve the problem of impedance matching with an electronic instrument, which has been a conventional problem, in an expression pedal. Conventionally, the power supply voltage supplied from the main body of an electronic instrument is divided by the volume variable resistor. In this case, the variable resistor value is large, from 10 kΩ to 50 kΩ, so that an A / D converter of the type that processes multiple channels (e.g., 8 channels) as one signal by an internal multiplexer, such as the sound source LSI of an electronic instrument, may not be able to detect an accurate value when detecting a voltage because the waveform is affected by the waveform of the previous time-division channel, and the waveform becomes dull.

[0050] Figure 4(a) shows an example of a waveform of a conventional voltage divider type output. By processing multiple channels in a time-division manner, the waveform output of one channel becomes comb-shaped as shown in Figure 4(a). In this case, the waveform becomes distorted due to the influence of a large voltage divider resistance value, and the correct voltage value may not be obtained at the timing of the time-division A / D conversion on the electronic musical instrument side.

[0051] Fig. 4(b) is a diagram showing an example of the waveform of the output voltage based on the PWM signal 130 in this embodiment. In the case of this embodiment, since an arbitrary voltage is output by the PWM signal 130, the problem of impedance matching between the electronic musical instrument and the expression pedal device 100 is eliminated, and the comb-shaped waveform output for one channel shown in Fig. 4(b) has almost no distortion, making it possible to obtain a correct voltage value at the timing of time-division A / D conversion on the electronic musical instrument side.

[0052] Not only in the above-mentioned cases, but according to the present invention, regardless of the state of the input on the instrument side, a signal wiring state known as low output, high input (output at low impedance, receive at high impedance) can be realized, making it possible to suppress signal degradation such as a reduction in high frequencies.

[0053] In this manner, in this embodiment, it is possible to correctly perform connection matching between an electronic musical instrument and the expression pedal device 100 regardless of the specifications of the electronic musical instrument.

[0054] In this embodiment, the internal battery 128 in Fig. 1 supplies power to each part in the control system 110 until a standard stereo phone plug cable is connected to the instrument connection jack unit 105 after the power switch 129 is turned on for the expression pedal device 100, but after the cable is connected and the electrical state of step S303 or S305 is determined by the process exemplified in the flowchart of Fig. 3, the control system can receive power supply from the electronic instrument via the third switch 116. In this case, by switching all power supplies including the microcomputer 111 from the battery 128 to the power supply from the electronic instrument (the output of the third switch 116), it is possible to significantly reduce consumption of the battery 128.

[0055] In this embodiment, an example has been described in which the electrical states of TIP contact 201 and RING contact 202 of a standard stereo phone plug are different, and SLEEVE contact 203 is fixed at ground level 209 (see FIG. 2). However, the same can be applied to cases in which the electrical state of SLEEVE contact 203 changes by monitoring its voltage level.

[0056] In the present embodiment, an example in which the technology of the present invention is applied to an expression pedal device has been described, but the present invention can also be applied to various foot pedals, effect pedals, and the like other than expression pedal devices.

[0057] The following supplementary notes are further disclosed regarding the above-described embodiment. (Appendix 1) an operation signal acquisition unit that acquires an operation signal corresponding to an operation performed by a performer; a pulse-width modulated signal generating unit that generates a pulse-width modulated signal having a modulation factor corresponding to a value of the operation signal and supplies the pulse-width modulated signal to an electronic musical instrument as a musical instrument signal; A musical instrument signal output device comprising: (Appendix 2) 2. The musical instrument signal output device according to claim 1, further comprising a level shifter at an output stage of the pulse width modulated signal, which converts the output level of the pulse width modulated signal to match the input level of the electronic musical instrument and outputs the converted signal. (Appendix 3) 3. The musical instrument signal output device according to claim 1, further comprising a low-pass filter at an output stage of the pulse-width modulated signal, which smoothes the pulse-width modulated signal and outputs the smoothed signal. (Appendix 4) Acquire an operation signal corresponding to an operation by a performer; generating a pulse-width modulated signal whose pulse width is modulated at a modulation factor corresponding to a value of the operation signal, and supplying the pulse-width modulated signal to an electronic musical instrument as a musical instrument signal; A method for controlling a musical instrument signal in a musical instrument signal output device. [Explanation of symbols]

[0058] 100 Expression Pedal 101 Pedal case part 102 Pedal section 103 Pedal rotation axis 104 LED display section 105 Instrument connection jack 110 Control System 111 Microcomputer 112 A / D conversion section 113 PWM signal generator 114 First Switch 115 Second Switch 116 Third Switch 117, 118 Resistance 119, 120, 121 Level shifter 122 LPF 123 Instrument Signals 124 Volume resistor 125 Batteries 126 Power Switch

Claims

1. an operation signal acquisition unit that acquires an operation signal corresponding to an operation by a player; a pulse-width modulated signal generating unit that generates a pulse-width modulated signal having a modulation factor corresponding to a value of the operation signal and supplies the pulse-width modulated signal to an electronic musical instrument as a musical instrument signal; a level shifter for converting a voltage level of the pulse width modulation signal; A first terminal and a second terminal; a first switch connected to the first terminal, the first switch having a first switch terminal and a second switch terminal; a second switch connected to the second terminal, the second switch having a first switch terminal and a second switch terminal; A third switch; A control unit; Equipped with The control unit is when a power supply voltage is input from the first terminal through the first switch, the power supply voltage is input to the level shifter through the first switch terminal of the first switch and the third switch, and the pulse width modulation signal converted by the level shifter is output to the second terminal through the second switch terminal of the second switch; a first switch, a second switch, and a third switch, the first switch, the second switch, and the third switch being controlled so that, when a power supply voltage is input from the second terminal through the second switch, the power supply voltage is input to the level shifter through the first switch terminal of the second switch and the third switch, and the pulse width modulation signal converted by the level shifter is output to the first terminal through the second switch terminal of the first switch.

2. Further comprising a battery; The control unit is 2. The musical instrument signal output device according to claim 1, wherein, in the case of an initialization process, the third switch is controlled so as to supply a voltage from the battery to the level shifter via the third switch.

3. 3. The musical instrument signal output device according to claim 1, further comprising a low-pass filter at an output stage of the pulse width modulated signal, which smoothes the pulse width modulated signal and outputs the smoothed signal.

4. A method for controlling a musical instrument signal in a musical instrument signal output device, comprising: The musical instrument signal output device includes: a pulse-width modulated signal generating unit that generates a pulse-width modulated signal having a modulation degree corresponding to a value of an operation signal corresponding to an operation by a player, and supplies the pulse-width modulated signal to an electronic musical instrument as a musical instrument signal; a level shifter for converting a voltage level of the pulse width modulation signal; A first terminal and a second terminal; a first switch connected to the first terminal, the first switch having a first switch terminal and a second switch terminal; a second switch connected to the second terminal, the second switch having a first switch terminal and a second switch terminal; A third switch; A control unit; Equipped with The control unit is when a power supply voltage is input from the first terminal through the first switch, the power supply voltage is input to the level shifter through the first switch terminal of the first switch and the third switch, and the pulse width modulation signal converted by the level shifter is output to the second terminal through the second switch terminal of the second switch; when a power supply voltage is input from the second terminal via the second switch, controlling the first switch, the second switch, and the third switch so as to input the power supply voltage to the level shifter via the first switch terminal of the second switch and the third switch, and to output the pulse width modulation signal converted by the level shifter to the first terminal via the second switch terminal of the first switch; Acquire the operation signal; the pulse-width modulated signal generating unit generates a pulse-width modulated signal whose pulse width is modulated at a modulation degree corresponding to a value of the operation signal, and supplies the pulse-width modulated signal as a musical instrument signal to the electronic musical instrument via the level shifter. A method for controlling a musical instrument signal in a musical instrument signal output device.

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