Electronic music synthesizer

Abstract

The utility model provides an electronic music synthesizer. The electronic music synthesizer comprises a sound sequencer module, a music synthesis module and a power amplifier module, the sound sequencer module is used for providing a sound sequence level signal; the music synthesis module is used for converting the phonetic sequence level signal into a sound waveform sequence composed of different musical scales, adjusting the musical scales and timbre of the sound waveform sequence, and outputting an audio signal; and the power amplifier module is used for amplifying the audio signal. According to the electronic music synthesizer, circuit design is carried out on the sound sequencer module, the music synthesis module and the power amplifier module, so that sound sequence level signals are converted into sound waveform sequences composed of different musical scales while it is guaranteed that the size of the electronic music synthesizer is small, and therefore the musical scales and timbres of various input sound sequence level signals can be flexibly adjusted; the problems that an existing electronic music synthesizer is large in size and poor in music adjusting performance are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit design, in particular to an electronic music synthesizer. Background Art

[0002] With the development of electronic technology, electronic music synthesizers came into being. They can create various unique sound effects and can be controlled and adjusted in real time, making music performances more flexible and personalized.

[0003] However, existing electronic music synthesizers, to provide more professional performance and a wider range of functions, are typically larger in size, while portable electronic music synthesizers often have fewer features. Furthermore, to minimize the size of electronic music synthesizers, a single button often has multiple functions. Therefore, flexible use requires proficiency in its usage, which takes a long time to master, making it difficult to get started. Furthermore, most existing electronic music synthesizers are digital, which offers limited flexibility in adjusting the music. Analog synthesizers, however, often use analog components, resulting in larger sizes.

[0004] Therefore, how to make the electronic music synthesizer compact in size while having comprehensive functions, excellent performance and high flexibility has become a technical problem that urgently needs to be solved in this field. Utility Model Content

[0005] The purpose of the utility model is to provide an electronic music synthesizer to solve the problems of large size and poor music adjustment performance of existing electronic music synthesizers.

[0006] To solve the above technical problems, the present invention provides an electronic music synthesizer, comprising a sequencer module, a music synthesis module and a power amplifier module; the sequencer module is used to provide a sequence level signal; the music synthesis module is used to convert the sequence level signal into a sound waveform sequence composed of different scales, and adjust the scale and timbre of the sound waveform sequence to output an audio signal; the power amplifier module is used to amplify the audio signal.

[0007] Optionally, in the electronic music synthesizer, the sequencer module includes a pulse signal generating circuit, a high level generating circuit, a clock signal selecting circuit, a pulse distribution circuit and a 16-way potentiometer; the pulse signal generating circuit is used to generate a pulse signal; the high level generating circuit is used to generate a high level signal, and the clock signal selecting circuit is used to select a pulse signal or a high level signal to be input into the pulse distributor; the pulse distribution circuit is used to perform pulse distribution on the input pulse signal; and the 16-way potentiometer is used to output the timing pulse signal after pulse distribution as a CV signal.

[0008] Optionally, in the electronic music synthesizer, the pulse signal generating circuit includes a timer chip, the model of which is NE555; the VCC terminal of the timer chip is connected to the power supply, and a first capacitor is connected between the VCC terminal and the GND terminal, the DISCH terminal is connected to the power supply through the first resistor, and the DISCH terminal is connected to the TRIG terminal and the THRES terminal through the second resistor and the adjustable resistor, the THRES terminal is grounded through the second capacitor, the CONT terminal is grounded through the third capacitor, the RESET terminal is connected to the power supply, and the OUT terminal outputs a pulse signal.

[0009] Optionally, in the electronic music synthesizer, the high-level generating circuit includes a switch, a fourth capacitor and a third resistor; the switch and the fourth capacitor are connected in parallel, and one end of the fourth capacitor is connected to a power supply, and the other end is grounded through the third resistor; a high-level signal is drawn between the fourth capacitor and the third resistor.

[0010] Optionally, in the electronic music synthesizer, the pulse distribution circuit includes two pulse distributors, the model of which is CD4017; the eight output ends of each pulse distributor are respectively connected to one of the 16 potentiometers to output the timing pulse signal after pulse distribution as a CV signal.

[0011] Optionally, in the electronic music synthesizer, the music synthesis module includes a voltage-controlled oscillator circuit and a mixing circuit; the voltage-controlled oscillator circuit is used to convert the sequence level signal into multiple groups of sound waveform sequences composed of different scales, and the sound waveform types of each group of sound waveform sequences are different, and the sound waveform types include sawtooth waves, rectangular waves and sine waves; the mixing circuit includes corresponding multiple input branches, each input branch is used to connect to a group of sound waveform sequences one by one, so as to use the mixing circuit to mix the sound waveform sequences and output the mixed audio signals.

[0012] Optionally, in the electronic music synthesizer, the power amplifier module includes a voltage amplifier stage, a driver stage, a pre-stage power amplifier output stage, a post-stage power amplifier output stage and a speaker circuit arranged in sequence; the voltage amplifier stage is used to receive an audio signal and perform voltage amplification on the audio signal; the driver stage is used to further amplify the voltage and current of the audio signal after voltage amplification to increase the amplitude of the audio signal, and filter the amplified audio signal; the pre-stage power amplifier output stage is used to filter and voltage amplify the audio signal output by the driver stage; the post-stage power amplifier output stage is used to perform current amplification on the audio signal; and the speaker circuit is used to play the amplified audio signal.

[0013] Optionally, in the electronic music synthesizer, the power amplifier module is a class AB audio power amplifier constituting an OTL power amplifier circuit.

[0014] Optionally, in the electronic music synthesizer, the electronic music synthesizer also includes a recording and playback module, which includes a receiving circuit and a recording and playback chip; the receiving circuit is used to collect sound and save it to the recording and playback chip under the control of the control switch; the recording and playback chip is used to play the collected sound through the power amplifier module under the control of the control switch.

[0015] Optionally, in the electronic music synthesizer, the electronic music synthesizer further includes a power supply module, the power supply module includes a power supply and a voltage conversion circuit, and the power supply and the voltage conversion circuit are used to power each module in the electronic music synthesizer.

[0016] The electronic music synthesizer provided by the utility model includes a sequencer module, a music synthesis module, and a power amplifier module; the sequencer module is used to provide a sequence level signal; the music synthesis module is used to convert the sequence level signal into a sound waveform sequence composed of different musical scales, adjust the scale and timbre of the sound waveform sequence, and output an audio signal; the power amplifier module is used to amplify the audio signal. By designing the circuits of the sequencer module, the music synthesis module, and the power amplifier module, the sequence level signal is converted into a sound waveform sequence composed of different musical scales while maintaining the electronic music synthesizer's small size, thereby enabling flexible and variable adjustment of the scale and timbre of various input sequence level signals, thereby solving the problem of existing electronic music synthesizers being large in size and having poor music adjustment performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of the electronic music synthesizer provided in this embodiment;

[0018] Figure 2 A schematic diagram of the structure of the sequencer module provided in this embodiment;

[0019] Figure 3 A circuit schematic diagram of a pulse signal generating circuit provided in this embodiment;

[0020] Figure 4 A circuit schematic diagram of a high level generating circuit provided in this embodiment;

[0021] Figure 5 A circuit schematic diagram of the clock signal selection circuit provided in this embodiment;

[0022] Figure 6 A circuit schematic diagram of the pulse distribution circuit provided in this embodiment;

[0023] Figure 7 The circuit diagram of the 16-way potentiometer provided in this embodiment;

[0024] Figure 8 A schematic diagram of the structure of the music synthesis module provided in this embodiment;

[0025] Figure 9 A circuit schematic diagram of a voltage-controlled oscillator circuit provided in this embodiment;

[0026] Figure 10 A circuit schematic diagram of the mixing circuit provided in this embodiment;

[0027] Figure 11 A schematic structural diagram of the power amplifier module provided in this embodiment;

[0028] Figure 12 A circuit diagram of the power amplifier module provided in this embodiment;

[0029] Figure 13 A schematic diagram of the structure of the recording and playback module provided in this embodiment;

[0030] Figure 14 A circuit diagram of the recording and playback module provided in this embodiment;

[0031] Figure 15 A flowchart of the electronic music synthesizer provided in this embodiment;

[0032] Figure 16 This is a test flow chart of the electronic music synthesizer provided in this embodiment. DETAILED DESCRIPTION

[0033] The electronic music synthesizer proposed in this utility model is further described in detail below, with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are highly simplified and not precisely scaled, serving only to facilitate and clearly illustrate the embodiments of this utility model. Furthermore, the structures shown in the drawings are often portions of the actual structure. In particular, different drawings may require different emphases and may use different scales.

[0034] It should be noted that the terms "first", "second", etc. in the specification, claims, and accompanying drawings of the present invention are used to distinguish similar objects in order to describe the embodiments of the present invention, and are not used to describe a specific order or sequence. It should be understood that the structures used in this way can be interchanged under appropriate circumstances. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or are inherent to these processes, methods, products, or apparatuses.

[0035] This embodiment provides an electronic music synthesizer, such as Figure 1 As shown, it includes a sequencer module, a music synthesis module and a power amplifier module; the sequencer module is used to provide a sequence level signal; the music synthesis module is used to convert the sequence level signal into a sound waveform sequence composed of different scales, and adjust the scale and timbre of the sound waveform sequence to output an audio signal; the power amplifier module is used to amplify the audio signal.

[0036] The electronic music synthesizer provided in this embodiment converts a sequence level signal into a sound waveform sequence composed of different musical scales while ensuring the electronic music synthesizer is compact by designing the circuits of the sequencer module, the music synthesis module, and the power amplifier module. This allows for flexible and varied adjustment of the musical scale and timbre of various input sequence level signals, thereby solving the problem of large size and poor music adjustment performance of existing electronic music synthesizers.

[0037] Furthermore, in this embodiment, Figure 2 As shown, the sequencer module includes a pulse signal generating circuit, a high level generating circuit, a clock signal selecting circuit, a pulse distribution circuit and a 16-way potentiometer; the pulse signal generating circuit is used to generate a pulse signal; the high level generating circuit is used to generate a high level signal, and the clock signal selecting circuit is used to select a pulse signal or a high level signal to be input to the pulse distributor; the pulse distribution circuit is used to perform pulse distribution on the input pulse signal; the 16-way potentiometer is used to output the timing pulse signal after pulse distribution as a CV signal.

[0038] Considering that in actual applications, the sequencers commonly used in electronic music synthesizers are mostly keyboards and electronic pianos, the sequencer records the force, pitch, and order of the keys pressed, generates a sequence, and plays it. Therefore, in actual applications, the 16-channel potentiometer can be a voltage knob type, continuously outputting 16-channel CV (control voltage) signals, and the CV signal can be changed by controlling the position of the potentiometer knob to produce different scales.

[0039] Furthermore, in this embodiment, the pulse signal generating circuit includes a timer chip. The chips commonly used to generate pulse signals include NE555, SG3525, AD9850, etc. Since the pulse signal frequency required by the pulse signal generating circuit block of this embodiment is low, considering the cost, the NE555 chip is selected to generate the pulse signal.

[0040] Specifically, in this embodiment, Figure 3 As shown, the VCC terminal of the timer chip is connected to the power supply (+9V), and the first capacitor C1 is connected between the VCC terminal and the GND terminal, the GND terminal is grounded, the DISCH terminal is connected to the power supply (+9V) through the first resistor R1, and the DISCH terminal is connected to the TRIG terminal and the THRES terminal through the second resistor R80 and the adjustable resistor RP1, the THRES terminal is grounded through the second capacitor C5, the CONT terminal is grounded through the third capacitor C4, the RESET terminal is connected to the power supply (+9V), and the OUT terminal outputs the pulse signal CLK.

[0041] The timer chip and its peripherals form a multivibrator, continuously generating a pulse signal. The frequency of the pulse signal is adjusted via adjustable resistor RP1; a higher resistance value results in a lower frequency. In practical applications, the capacitance of first capacitor C1 is approximately 0.1μF; the resistance of first resistor R1 is approximately 1kΩ; adjustable resistor RP1 can be a potentiometer with an adjustable resistance range of 0 to 50kΩ; the capacitance of second capacitor C5 is approximately 10μF; and the capacitance of third capacitor C4 is approximately 0.01μF.

[0042] And, in this embodiment, if Figure 4 As shown, the high-level generating circuit includes switches SW1 / SW2, fourth capacitors C2 / C3 and third resistors R2 / R3; the switch and the fourth capacitor are connected in parallel, and one end of the fourth capacitor is connected to a power supply (+9V) and the other end is grounded through the third resistor; a high-level signal SINGLE is drawn between the fourth capacitor and the third resistor.

[0043] In practical applications, the switch may be a push-button switch, such as Figure 4 As shown in the circuit on the left, when the switch SW1 is closed, the output is the reset signal RST (low level); Figure 4 As shown in the circuit on the right, when the switch SW2 is turned on, the output is a high-level signal SINGLE, so that a single syllable can be played by pressing the key.

[0044] exist Figure 4 In the high level generating circuit shown, the capacitance of the fourth capacitor is approximately 0.1 μF, and the resistance of the third resistor is approximately 10 kΩ.

[0045] And, in this embodiment, if Figure 5 As shown, the clock signal selection circuit is a single-pole double-throw switch, so that the signal input to the pulse distribution circuit is selected as the pulse signal CLK or the high-level signal SINGLE by switching the switch.

[0046] Further, such as Figure 6 As shown, the pulse distribution circuit includes two pulse distributors U3 and U4, and the model of the pulse distributor is CD4017; the 8 output ends of each pulse distributor are respectively connected to one of the 16-way potentiometers to output the timing pulse signal after pulse distribution as a CV signal.

[0047] The pulse distributor's function is to sequentially control the output potential based on the input pulse signal to generate sequential pulse signals. Commonly used chips for pulse distributor circuits include the CD4017, 74LS138, and 74LS164. In this embodiment, since 16 sequential pulses need to be output, using a decoder or register chip would require multiple chips, resulting in a complex circuit and large board space. However, the CD4017 chip can directly distribute pulses, requiring only two chips to meet the requirements. Therefore, the CD4017 chip was selected as the pulse distributor.

[0048] Specifically, in this embodiment, Figure 6 As shown, in order to connect the previous and next audio sequences and make the clock signals consistent, the pulse distribution circuit uses the relay K1 switch circuit. In this way, when U3 completes the 8-way audio sequence output, the Q8 pin is triggered to output a high level, causing the transistor Q1 to conduct, the indicator LED4 to light up, and the internal coil of the relay K1 to be powered on to produce an electromagnetic effect. Pin 5 will become disconnected and pin 6 will be closed. Therefore, the clock signal transmission object of pin 1 is switched from the initial U3 to U4, and U4 then completes the audio sequence output. D19 is a freewheeling diode, which is used to provide a power consumption circuit for the inductor coil in the relay when the transistor is cut off to prevent the current generated by it from damaging the circuit. Combined with Figure 4 As shown in the circuit on the left, SW1, C2, and R2 form a reset circuit. The first syllable of U4 should start from the Q1 pin, otherwise it will conflict with the first syllable of U3 during reset.

[0049] As well as Figure 7 As shown, each of the 16-way potentiometers is provided with a light-emitting diode (LED5 to LED21) to emit an indicator light for the corresponding syllable, facilitating operation and maintenance.

[0050] Furthermore, in this embodiment, Figure 8As shown, the music synthesis module includes a voltage-controlled oscillator circuit and a mixing circuit, both of which are designed using operational amplifiers. The voltage-controlled oscillator circuit is used to convert the sequence level signal into multiple groups of sound waveform sequences composed of different scales. The sound waveform types of each sound waveform sequence are different, including sawtooth waves, rectangular waves, and sine waves. The mixing circuit includes multiple corresponding input branches, each input branch is used to receive a group of sound waveform sequences in a one-to-one correspondence, so that the mixing circuit can mix the sound waveform sequences and output the mixed audio signal.

[0051] Preferably, the voltage-controlled oscillator circuit is used to convert the sequence level signal into three groups of sound waveform sequences composed of different scales, and the mixing circuit includes three input branches, each input branch is used to connect to a group of sound waveform sequences in a one-to-one correspondence, and the sound waveform types in the three groups of sound waveform sequences are sawtooth waves, rectangular waves and sine waves, respectively, so that the three groups of sound waveform sequences corresponding to the three sound waveform types of sawtooth waves, rectangular waves and sine waves are mixed by using the mixing circuit and the mixed audio signals are output.

[0052] The voltage-controlled oscillator (VCO) module is the core component of a music synthesizer, responsible for converting the level signal of the musical sequence into sound waveforms. The more sound waveforms a synthesizer can produce, the more timbres and effects it can create. In this embodiment, a sound waveform sequence includes three types of sound waveforms: sawtooth, rectangular, and sine. Controlled by the same voltage value, these three waveforms should have equal periodic frequency, minimal amplitude difference, and be independent of each other without interfering with each other.

[0053] Specifically, in this embodiment, the voltage-controlled oscillator module primarily utilizes audio operational amplifiers and Schmitt triggers. Common audio op amps include the NE5532, LM837, and TL074. This embodiment uses the four-channel TL074, taking into account the balance between overall circuit layout and performance. Schmitt trigger chips vary widely, and selection primarily considers noise and operating voltage. Mainstream models include the 74HC14 and CD40106. This embodiment selects the CD40106 chip, taking into account the chip's operating voltage compatibility.

[0054] The voltage controlled oscillator circuit provided in this embodiment is as follows Figure 9As shown in the figure, U6, D20, C12, and Q18 form a sawtooth voltage-controlled oscillator (VCO), which generates a sawtooth waveform controlled by a CV signal. C17 is a DC-blocking capacitor. The sawtooth waveform is buffered by the U5D voltage follower and output directly on one path. The other path is converted to a rectangular wave by the U5C zero-crossing comparator. The rectangular wave is shaped by a Schmitt trigger and then buffered by the U13C voltage follower. One path is output directly, while the other path is converted to a sine wave by an RC oscillator phase-shift network and output. R61 and R70 are noise-reducing resistors. To prevent signal reflections, matching resistors are placed at R62 and R63. The ground plane is split into signal ground GND3 and power ground AGND2, both of which are connected to a single point via a 0Ω resistor. Unused operational amplifiers are connected as ground plane voltage followers to prevent interference with other operational amplifiers.

[0055] Since the conversion of multiple waveforms is involved, this embodiment sets a voltage follower in the circuit to act as an isolation buffer, which copies the waveform without interfering with the original waveform and simplifies the circuit.

[0056] And, the mixing circuit provided in this embodiment is as follows Figure 10 As shown, the adder circuit uses a TL074 operational amplifier chip. The three waveforms generated by the voltage-controlled oscillator circuit are not directly output to the speaker. Instead, they are selected by switches SW6, SW7, and SW11. Only the selected waveform enters the adder circuit connected to U13D. C13 is a filter capacitor. The mixed waveform is buffered by the voltage follower U13A before being output. R79 suppresses noise. RP21-RP23 are gain potentiometers. The larger the resistance of the potentiometer connected to the circuit, the higher the level of the corresponding waveform, and the greater its contribution to the mixed waveform.

[0057] Furthermore, in this embodiment, Figure 11As shown, the power amplifier module includes a voltage amplifier stage, a driver stage, a power amplifier output stage (including a pre-amplifier output stage and a post-amplifier output stage), and a speaker circuit, which are arranged in sequence. The voltage amplifier stage is used to receive an audio signal and amplify the audio signal to a certain voltage level. The number of voltage amplifier stages can be adjusted according to different audio output power requirements. If the input signal is a low signal, a multi-stage voltage amplifier is usually used. The driver stage is used to further amplify the voltage and current of the amplified audio signal to increase the amplitude of the audio signal, and filter the amplified audio signal. The output stage amplifies the signal current, which, combined with the voltage amplification of the signal by the pre-amplifier, achieves power amplification of the audio signal to achieve the power required to drive the speaker. The pre-amplifier output stage, placed between the sound source and the post-amplifier output stage, is primarily responsible for filtering and voltage amplifying the input signal, completing initial signal amplification. The pre-amplifier output stage is designed with high input impedance and low output impedance to achieve impedance conversion and matching. The post-amplifier output stage, placed between the pre-amplifier output stage and the speaker, primarily amplifies the current to achieve signal power amplification, outputting sufficient power to drive the speaker. In short, the pre-amplifier output stage is primarily responsible for adjusting sound quality and providing an appropriate audio level signal, which is the component that has the greatest impact on timbre. The post-amplifier output stage simply amplifies the pre-amplifier output signal to drive the speaker. The speaker circuit is used to play the amplified audio signal.

[0058] Preferably, in this embodiment, the power amplifier module is a class AB audio power amplifier that constitutes an OTL power amplifier circuit. The class AB power amplifier adds a static bias current, so that the initial state of the transistor is a slightly conductive state, skipping the cutoff region. When there is a signal input, it can directly enter the transistor amplification region, solving the crossover distortion problem. At the same time, the static bias current added by this type of power amplifier is very small, which will not cause power consumption problems like class A power amplifiers, and the output power can also reach the level of class B power amplifiers, and the efficiency can reach 65%. The OTL (Output Transformer Less, output transformer-free power amplifier circuit) circuit can filter out the DC component of the power supply in the signal, and its output waveform is limited by the power supply voltage, which is suitable for low-power output application scenarios. Therefore, in this embodiment, a class AB audio power amplifier is selected to form an OTL power amplifier circuit. Under the condition of a single 12V power supply, the maximum output power of the speaker with an impedance of 8Ω is 1W, the output waveform has no obvious distortion, and the volume is adjustable.

[0059] In practical applications, commonly used chip models for Class AB audio amplifiers include the LM1875, LM3886, and TDA2030. All three audio amplifiers can be powered by a single power supply, but the LM3886 has a more complex peripheral circuit; the LM1875 has higher output power and slightly higher heat generation; the TDA2030 has lower distortion and higher noise suppression capabilities, and its output power is suitable for low-power scenarios. This embodiment takes into account the excellent performance of the chip TDA2030, with rich and clear output sound quality. The chip maintains high power output within the frequency range of 40 to 15kHz and has extremely low distortion. Depending on the power supply type, dual or single power supply can be selected. It has fewer peripheral components, a simple circuit, and can reduce the board area. Therefore, the TDA2030 is selected as the audio amplifier module chip.

[0060] Specifically, the circuit diagram of the power amplifier module provided in this embodiment is as follows Figure 12 As shown, the Class AB audio amplifier chip TDA2030 serves as a non-inverting proportional amplifier, which, along with peripheral components, forms an OTL single-supply amplifier circuit. U11 is the audio input interface, and RP12 is a volume potentiometer, used to adjust the input signal level. Signal strength varies with the resistance through which the signal flows; higher signal strength increases the volume. C23 is an input coupling capacitor, and R73 short-circuits any noise in the audio input, eliminating background noise. Because the amplifier operates from a single power supply, the negative half-cycle of the signal cannot enter the amplifier. Therefore, a DC bias circuit consisting of R32, R37, and C24 is implemented to raise the reference voltage at the non-inverting terminal to 12VCC. R34 is an isolation resistor, and C20, C21, and C24 are power coupling capacitors to reduce the possibility of self-oscillation in the op amp. R32, R35, and C25 form a negative feedback circuit; adjusting their resistance values ​​adjusts the op amp gain. D11 and D12 are freewheeling diodes. When the op amp stops operating, the inductor inside the speaker generates a voltage output, potentially breaking down the op amp output. Freewheeling diodes provide a discharge path to protect the op amp. R37 and C26 form an RC damping circuit to prevent self-oscillation, improve phase distortion, and enhance stability. C22, the output coupling capacitor, blocks DC and passes AC, removing the DC component of the signal at the non-inverting terminal and also provides power for the lower power transistor inside the amplifier. U12 is the audio output interface, connected to the speaker.

[0061] This embodiment takes into account that the audio power amplifier circuit needs to pay special attention to the signal noise problem, that is, there should be no noise output when there is no input signal, and the input signal should have small burrs and basically no distortion after amplification. Therefore, the ground plane is divided into input signal ground GND1, output signal ground GND2, and power ground AGND2. Finally, single-point grounding is completed with the power ground AGND2 through R4 and R8. The resistance value of 10Ω is beneficial to improving the signal-to-noise ratio of the power amplifier.

[0062] Furthermore, considering that the process of music creation often requires recording instant inspiration, and the existing music synthesizer has no memory function and cannot save the music settings, therefore, in this embodiment, Figure 1 As shown, the electronic music synthesizer also includes a recording and playback module.

[0063] Specifically, the recording and playback module includes a receiving circuit and a recording and playback chip; the receiving circuit is used to record the sound under the control of the control switch and save it to the recording and playback chip; the recording and playback chip is used to play the recorded sound through the power amplifier module under the control of the control switch. Figure 13 As shown, the sound receiving circuit includes a microphone-type sound receiving device; the control switch includes a recording switch and a playback switch to flexibly control the recording process and the playback process; the recording and playback chips mainly include OTP voice chips, FLASH voice chips, MP3 voice chips, and TTS voice chips. Considering that the recording and playback module of this embodiment needs to change the format of the audio file or the microphone reception file, a FLASH voice chip is selected; commonly used FLASH voice chips include the ISD series and the domestic WT588D, and only the ISD series is a microphone reception form, so the ISD series voice chip is selected as the recording and playback chip.

[0064] The circuit structure of the recording and playback module provided in this embodiment is as follows Figure 14 As shown, a linear regulator AMS1117-5.0 is used to step down the power supply voltage to provide a 5V supply voltage for the recording chip ISD1820. This circuit is designed based on the classic application circuit of the ISD1820 chip. C8 and C9 are input voltage filter capacitors, C6 and C7 are output voltage filter capacitors, and SW5 is the main power switch for the recording module. It is turned off by default when the recording function is not in use to reduce system power consumption and extend battery life. The U8 peripheral circuit is designed primarily based on the ISD1820 chip manual. C29 and C30 are microphone coupling capacitors, SW10 is the recording button, LED9 is the recording indicator, and R41 is a 200kΩ resistor to meet the 20s recording requirement. The ISD1820 chip has three trigger modes: level trigger, edge trigger, and switch-on. The first two modes only play the audio once, while the latter allows looping. Therefore, this embodiment uses a switch-on mode, with SW9 as the continuous playback switch. Pins 7 and 9 of U8 can directly drive the speaker to produce sound, but the volume cannot be adjusted. Therefore, when playing audio, connect pin 9 to the audio amplifier module and leave pin 7 floating.

[0065] Furthermore, in this embodiment, Figure 1 As shown, the electronic music synthesizer further includes a power supply module, which includes a power supply and a voltage conversion circuit. The power supply and the voltage conversion circuit are used to supply power to each module in the electronic music synthesizer.

[0066] The electronic music synthesizer provided in this embodiment has the following working process: Figure 15 As shown, the main process is: after the system is started, the sequencer module starts to continuously output the sequence level signal; then, the sequence level signal enters the voltage-controlled oscillator circuit, and the oscillation frequency of the oscillator is controlled by the level signal. Different oscillation frequencies correspond to different scales, so that the level signal sequence is converted into a set of sound waveform sequences composed of different scales, and an audio signal is generated. The user can adjust the scale in the sequencer module; the voltage-controlled oscillator module outputs three sound waveforms, namely sawtooth wave, rectangular wave, and sine wave. The desired timbre can be selected through the mixing circuit; after the scale and timbre of the audio signal are adjusted in the sequencer and voltage-controlled oscillator parts, it enters the power amplifier module for amplification processing, and the user can adjust the playback volume in the power amplifier module; the recording and playback module is an additional module and is used on demand. When playing, the sound source input of the power amplifier should be switched to the output of the recording and playback module.

[0067] The electronic music synthesizer provided in this embodiment is tested for functionality, and the test process is as follows: Figure 16 The test results are summarized as follows:

[0068] Voltage-controlled oscillator test results: The actual output waveform frequency range of the voltage-controlled oscillator covers the 100Hz to 20kHz band. At the same control voltage, the three waveforms have nearly identical frequencies, and the waveforms are independently output without crosstalk. Test results show that at low frequencies, the peak values ​​of the three waveforms are similar. As the output frequency increases, the peak values ​​decrease, with the sawtooth and rectangular waves experiencing a smaller decrease, while the sine wave is more affected. The peak-to-peak range for the sawtooth waveform is approximately 1.2 to 2.0V, the peak-to-peak range for the rectangular waveform is approximately 1.6 to 3.3V, and the peak-to-peak range for the sine wave is approximately 0.8 to 2.0V.

[0069] Power amplifier module test results: The sawtooth wave, rectangular wave, and sine wave output by the voltage-controlled oscillator module are connected to the power amplifier in sequence. The output waveform of the power amplifier is observed, and the effective values ​​of the input and output voltages are measured. The obtained data are shown in Table 1:

[0070]

[0071]

[0072] Table 1. Data obtained after the three waveforms are input into the power amplifier module

[0073] During testing, all three waveforms exhibited varying degrees of distortion in the low-frequency range, but distortion was acceptable and minimal in the mid- and high-frequency ranges. The amplifier module's gain factor was approximately 200, and the maximum output power driving an 8Ω speaker should reach 1W. Table 1 shows that the sawtooth wave had an average gain factor of approximately 199.9, a maximum output voltage of 3.69V RMS, and a maximum output power of approximately 1.70W. The rectangular wave had an average gain factor of approximately 200.6, a maximum output voltage of 2.67V RMS, and a maximum output power of approximately 0.89W. The sine wave had an average gain factor of approximately 195.7, a maximum output voltage of 2.34V RMS, and a maximum output power of approximately 0.68W.

[0074] Test results of the electronic music synthesizer: It can output 16-channel sound sequences, and can output three sound waveforms: sawtooth wave, rectangular wave, and sine wave, and covers the frequency band of 100Hz to 20kHz. The maximum output power of the audio amplifier is 1.70W. The output waveform has different degrees of distortion in the low frequency band and less distortion in the medium and high frequency bands. The maximum recording time can reach 20 seconds.

[0075] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other. In addition, the different parts between the various embodiments can also be used in combination with each other, and this utility model does not limit this.

[0076] The electronic music synthesizer provided in this embodiment includes a sequencer module, a music synthesis module, and a power amplifier module; the sequencer module is used to provide a sequence level signal; the music synthesis module is used to convert the sequence level signal into a sound waveform sequence composed of different musical scales, adjust the scale and timbre of the sound waveform sequence, and output an audio signal; the power amplifier module is used to amplify the audio signal. By designing the circuits of the sequencer module, the music synthesis module, and the power amplifier module, the sequence level signal is converted into a sound waveform sequence composed of different musical scales while maintaining the electronic music synthesizer's small size, thereby enabling flexible and variable adjustment of the scale and timbre of various input sequence level signals, thereby solving the problem of existing electronic music synthesizers being large in size and having poor music adjustment performance.

[0077] The above description is only a description of the preferred embodiment of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. An electronic music synthesizer, characterized in that: It includes a sequencer module, a music synthesis module and a power amplifier module; the sequencer module is used to provide a sequence level signal; the music synthesis module is used to convert the sequence level signal into a sound waveform sequence composed of different scales, and adjust the scale and timbre of the sound waveform sequence to output an audio signal; the power amplifier module is used to amplify the audio signal.

2. The electronic music synthesizer according to claim 1, characterized in that The sequencer module includes a pulse signal generating circuit, a high-level generating circuit, a clock signal selecting circuit, a pulse distribution circuit and a 16-way potentiometer; the pulse signal generating circuit is used to generate a pulse signal; the high-level generating circuit is used to generate a high-level signal, and the clock signal selecting circuit is used to select a pulse signal or a high-level signal to be input into the pulse distributor; the pulse distribution circuit is used to perform pulse distribution on the input pulse signal; the 16-way potentiometer is used to output the timing pulse signal after pulse distribution as a CV signal.

3. The electronic music synthesizer according to claim 2, characterized in that The pulse signal generating circuit includes a timer chip, the model of which is NE555; the VCC terminal of the timer chip is connected to the power supply, and a first capacitor is connected between the VCC terminal and the GND terminal, the DISCH terminal is connected to the power supply through the first resistor, and the DISCH terminal is connected to the TRIG terminal and the THRES terminal through the second resistor and the adjustable resistor, the THRES terminal is grounded through the second capacitor, the CONT terminal is grounded through the third capacitor, the RESET terminal is connected to the power supply, and the OUT terminal outputs a pulse signal.

4. The electronic music synthesizer according to claim 2, characterized in that The high-level generating circuit includes a switch, a fourth capacitor and a third resistor; the switch and the fourth capacitor are connected in parallel, and one end of the fourth capacitor is connected to a power supply and the other end is grounded through the third resistor; a high-level signal is drawn between the fourth capacitor and the third resistor.

5. The electronic music synthesizer according to claim 2, characterized in that The pulse distribution circuit includes two pulse distributors, the model of which is CD4017; the eight output ends of each pulse distributor are respectively connected to one of the 16-way potentiometers to output the timing pulse signal after pulse distribution as a CV signal.

6. The electronic music synthesizer according to claim 1, characterized in that The music synthesis module includes a voltage-controlled oscillator circuit and a mixing circuit; the voltage-controlled oscillator circuit is used to convert a sequence level signal into multiple groups of sound waveform sequences composed of different scales, and the sound waveform types of each group of sound waveform sequences are different, and the sound waveform types include sawtooth waves, rectangular waves and sine waves; the mixing circuit includes corresponding multiple input branches, each input branch is used to connect to a group of sound waveform sequences in a one-to-one correspondence, so that the sound waveform sequences are mixed by using the mixing circuit and the mixed audio signal is output.

7. The electronic music synthesizer according to claim 1, characterized in that The power amplifier module includes a voltage amplifier stage, a driver stage, a pre-stage power amplifier output stage, a post-stage power amplifier output stage and a speaker circuit arranged in sequence; the voltage amplifier stage is used to receive an audio signal and perform voltage amplification on the audio signal; the driver stage is used to further amplify the voltage and current of the audio signal after voltage amplification to increase the amplitude of the audio signal, and filter the amplified audio signal; the pre-stage power amplifier output stage is used to filter and voltage amplify the audio signal output by the driver stage; the post-stage power amplifier output stage is used to perform current amplification on the audio signal; and the speaker circuit is used to play the amplified audio signal.

8. The electronic music synthesizer according to claim 1, characterized in that The power amplifier module is a class AB audio power amplifier that forms an OTL power amplifier circuit.

9. The electronic music synthesizer according to claim 1, characterized in that The electronic music synthesizer also includes a recording and playback module, which includes a receiving circuit and a recording and playback chip; the receiving circuit is used to record sound and save it to the recording and playback chip under the control of the control switch; the recording and playback chip is used to play the recorded sound through the power amplifier module under the control of the control switch.

10. The electronic music synthesizer according to claim 1, characterized in that The electronic music synthesizer further comprises a power supply module, which comprises a power supply and a voltage conversion circuit. The power supply and the voltage conversion circuit are used to supply power to various modules in the electronic music synthesizer.

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