Anti-howling and anti-self-excitation system and method for intelligent electric guitar

Abstract

The invention discloses an anti-howling and anti-self-excitation integrated system and method for an intelligent electric guitar. The system comprises a control mainboard arranged in an electric guitar body, a loudspeaker and a power supply module for supplying power to each unit, an audio processing unit is integrated on the control mainboard and comprises an analog audio processing circuit, a digital signal processor and a power amplifier; the system receives an analog signal of an electric guitar pickup through the audio processing unit, and outputs the analog signal to the power amplifier after analog-to-digital conversion, digital sound effect processing, howling suppression processing and digital-to-analog conversion; the power amplifier drives the loudspeaker to produce sound; the loudspeaker is suspended and fixed in the electric guitar body through a shockproof structure, and the loudspeaker is in non-rigid connection with the electric guitar body.

Description

Technical Field

[0001] This invention relates to the field of electroacoustic musical instruments and embedded audio systems, specifically to an anti-feedback and anti-self-oscillation system and method for an intelligent electric guitar. Background Technology

[0002] Existing electric guitar amplification and sound processing solutions mainly rely on external amplifiers, pedal effects, or rack-mount equipment. While these traditional solutions can provide a rich range of tones, they have obvious limitations: First, they are not portable, requiring users to carry and connect multiple external devices, making them difficult to use and unable to meet the needs of mobile performance.

[0003] To address portability issues, some products have attempted to integrate small speakers and amplifier circuits inside electric guitars. However, these built-in solutions generally suffer from the following problems due to design flaws: First, the amplifier output power is insufficient, resulting in low volume that is difficult to meet the needs of performance; second, due to the limited space inside the guitar body, acoustic feedback and electromagnetic coupling are easily formed between the pickup and the speaker, causing severe howling and self-oscillation, which seriously affects the user experience; third, their circuits often use simple analog designs and single power supplies, resulting in low signal-to-noise ratios, narrow dynamic ranges, and high noise levels, leading to instability at high gain and poor sound quality; fourth, they are limited in functionality, lacking digital sound processing capabilities and unable to achieve modern sound effects such as reverb and delay. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide an intelligent electric guitar anti-feedback and anti-self-oscillation integrated system, comprising:

[0005] The control board, speakers, and power modules that supply power to each unit are located inside the electric guitar body;

[0006] The control motherboard integrates an audio processing unit, which includes an analog audio processing circuit, a digital signal processor, and a power amplifier.

[0007] The system receives the analog signal from the electric guitar pickup through the audio processing unit, and outputs it to the power amplifier after analog-to-digital conversion, digital sound effect processing, feedback suppression processing, and digital-to-analog conversion.

[0008] The power amplifier drives the speaker to produce sound;

[0009] The speaker is suspended and fixed to the electric guitar body by a shock-absorbing structure, and there is no rigid connection between the speaker and the electric guitar body.

[0010] Preferably, the power module includes a first low-dropout linear stabilizer and a second low-dropout linear stabilizer;

[0011] The first low-dropout linear stabilizer is used to power the analog audio processing circuit;

[0012] The second low-dropout linear stabilizer is used to power the digital signal processor;

[0013] The power supply circuits of the first low-dropout linear stabilizer and the second low-dropout linear stabilizer are isolated from each other.

[0014] Preferably, the power module further includes a charge pump chip for generating a negative voltage;

[0015] The negative voltage and the positive voltage generated by the first low-dropout linear stabilizer together form a dual-power supply architecture for the analog audio processing circuit.

[0016] Preferably, the power amplifier is a digital Class D audio power amplifier that integrates a hardware digital signal processing core.

[0017] Preferably, the digital signal processor is used for a motion howling suppression algorithm, the howling suppression algorithm comprising:

[0018] The input digital audio signal is framed and subjected to Fast Fourier Transform to obtain the frequency domain signal;

[0019] Analyze the rate of energy change at each frequency point in the frequency domain signal;

[0020] The frequency points with energy change rates set to a preset threshold are identified as potential howling frequencies;

[0021] A digital notch filter corresponding to the potential howling frequency is generated and attenuated at that frequency.

[0022] Preferably, the digital signal processor is also used to implement at least one digital sound effect among reverb, delay, and chorus.

[0023] Preferably, the control motherboard also integrates a Bluetooth audio receiving module, which receives external audio data and transmits it to the digital signal processor for processing.

[0024] Preferably, the analog audio processing circuit includes a distortion effect circuit, which includes a soft clipping circuit composed of an operational amplifier and diodes.

[0025] Preferably, the electric guitar body has an acoustic cavity for mounting the speaker, the inner wall of the acoustic cavity is provided with sound-absorbing material, and its structure is designed to enhance the guidance and response of low-frequency sound waves.

[0026] A method for suppressing feedback on electric guitars, applied to the digital signal processor of a smart electric guitar anti-feedback and anti-self-oscillation integrated system, includes the following steps:

[0027] S1. Receives digitized audio signals;

[0028] S2. The audio signal is framed and time-frequency transformed to obtain spectral information;

[0029] S3. Analyze the spectrum information to identify frequency points where energy rises abnormally and rapidly;

[0030] S4. Generate a digital filter to selectively attenuate the frequency points;

[0031] S5. Outputs the attenuated audio signal.

[0032] The above-described solution of the present invention has at least the following beneficial effects:

[0033] When the system is working, the analog audio signal generated by the electric guitar's pickup is first sent to the analog audio processing circuit on the control board for preliminary conditioning (such as amplification and distortion). Subsequently, the signal is converted from analog to digital and sent to a digital signal processor (DSP). The DSP is the core of the system, responsible for performing two key tasks: first, running a feedback suppression algorithm. This algorithm performs real-time frequency domain analysis of the audio signal, calculates the rate of energy change at each frequency point through Fast Fourier Transform (FFT), intelligently identifies specific frequencies that may trigger feedback, and dynamically generates a high-quality digital notch filter to precisely attenuate those frequencies, thus suppressing feedback before it occurs; second, implementing various digital sound effects processing, such as reverb, delay, and chorus, greatly enriching the guitar's tone.

[0034] The processed digital signal is then converted from digital to analog and fed into a digital Class-D power amplifier. This amplifier is highly efficient and has low distortion, enabling it to drive speakers to produce sufficient volume. Simultaneously, the power module provides isolated, clean power to the analog and digital circuits, fundamentally reducing noise and interference introduced by power coupling.

[0035] Finally, at the structural level, the speaker is suspended and fixed to the body of the instrument by a shock-absorbing structure (such as a silicone damping ring), and has no rigid connection with the wooden body. This design cuts off the path of mechanical vibration transmission, greatly weakens the energy of acoustic feedback, and further reduces the possibility of howling from a physical perspective.

[0036] Through the combined effect of three measures—pre-set software algorithm (DSP real-time notch filtering), hardware design (power isolation), and physical structure (speaker suspended and fixed)—a multi-layered and three-dimensional anti-feedback solution is formed, solving the inherent acoustic feedback problem of built-in speaker guitars.

[0037] It adopts a high-performance digital Class D amplifier, which provides ample driving power and low distortion audio output while ensuring high efficiency and low heat generation, thus ensuring a grand volume and excellent sound quality.

[0038] The system integrates a variety of professional digital sound effects (such as reverb and delay), allowing users to obtain rich tones without the need for external effects processors, greatly enhancing the product's practicality and entertainment value. At the same time, all functions are built into the instrument body, making it extremely portable.

[0039] The system employs a power supply architecture that separates and isolates analog and digital power supplies, effectively blocking digital noise from interfering with analog signals. This significantly improves the system's signal-to-noise ratio and operational stability, maintaining a clear and pure tone even at high gain settings.

[0040] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0042] Figure 1 This is a flowchart of an intelligent electric guitar anti-feedback and anti-self-oscillation integrated system provided in an embodiment of the present invention;

[0043] Figure 2 This is a circuit diagram of the power supply module provided in an embodiment of the present invention;

[0044] Figure 3 This invention provides an analog audio processing circuit diagram in an embodiment of the invention;

[0045] Figure 4 This is a circuit diagram showing the distortion effect provided in an embodiment of the present invention;

[0046] Figure 5 This is a digital audio processing circuit diagram provided in an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the structure of an electric guitar body provided in an embodiment of the present invention;

[0048] Figure 7 This is a schematic diagram of the acoustic cavity provided in an embodiment of the present invention;

[0049] Figure 8 yes Figure 7 A schematic diagram of the AA cross-sectional structure;

[0050] Figure 9 This is a flowchart of a method for suppressing howling in an electric guitar, provided in an embodiment of the present invention.

[0051] Explanation of icon numbers:

[0052] 1. Electric guitar body, 2. Acoustic cavity, 3. Speaker.

[0053] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0054] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0055] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "circumferential," and "radial," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0057] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0059] The following is a detailed description of an intelligent electric guitar anti-whistling and anti-self-oscillation integrated system according to an embodiment of the present invention, with reference to the accompanying drawings.

[0060] Please see Figures 1-9 In this embodiment, the system includes: a control board, a speaker 3, and a power supply module for each unit, all housed within the electric guitar body 1. The control board integrates an audio processing unit, which includes an analog audio processing circuit, a digital signal processor, and a power amplifier. The system receives analog signals from the electric guitar pickups through the audio processing unit, and outputs them to the power amplifier after analog-to-digital conversion, digital sound effect processing, feedback suppression processing, and digital-to-analog conversion. The power amplifier drives the speaker 3 to produce sound. The speaker 3 is suspended and fixed within the electric guitar body 1 by a shock-absorbing structure, and there is no rigid connection between the speaker 3 and the electric guitar body 1.

[0061] When the system is working, the analog audio signal generated by the electric guitar's pickup is first sent to the analog audio processing circuit on the control board for preliminary conditioning (such as amplification and distortion). Then, the signal is converted from analog to digital and sent to the digital signal processor (DSP). The DSP is the core of the system, responsible for performing two key tasks: first, running a feedback suppression algorithm. This algorithm performs real-time frequency domain analysis of the audio signal, calculates the rate of energy change at each frequency point through Fast Fourier Transform (FFT), intelligently identifies specific frequencies that may trigger feedback, and dynamically generates a high-quality digital notch filter to precisely attenuate those frequencies, thus suppressing feedback before it occurs; second, implementing various digital sound effects processing, such as reverb, delay, and chorus, greatly enriching the guitar's tone.

[0062] The processed digital signal is then converted from digital to analog and sent to a digital Class-D power amplifier. This amplifier is highly efficient and has low distortion, enabling it to drive speaker 3 to produce sufficient volume. Simultaneously, the power module provides isolated, clean power to the analog and digital circuits, fundamentally reducing noise and interference introduced by power coupling.

[0063] Finally, at the structural level, speaker 3 is suspended and fixed to the body of the instrument through a shock-absorbing structure (such as a silicone damping ring), without a rigid connection to the wooden body; this design cuts off the path of mechanical vibration transmission, greatly weakens the energy of acoustic feedback, and further reduces the possibility of howling from a physical perspective.

[0064] Through the combined effect of three measures—pre-set software algorithm (DSP real-time notch filtering), hardware design (power isolation), and physical structure (speaker 3 suspended and fixed)—a multi-layered and three-dimensional anti-feedback solution is formed, which solves the inherent acoustic feedback problem of built-in speaker guitars.

[0065] It adopts a high-performance digital Class D amplifier, which provides ample driving power and low distortion audio output while ensuring high efficiency and low heat generation, thus ensuring a grand volume and excellent sound quality.

[0066] The system integrates a variety of professional digital sound effects (such as reverb and delay), allowing users to obtain rich tones without the need for external effects processors, greatly enhancing the product's practicality and entertainment value. At the same time, all functions are built into the instrument body, making it extremely portable.

[0067] The system employs a power supply architecture that separates and isolates analog and digital power supplies, effectively blocking digital noise from interfering with analog signals. This significantly improves the system's signal-to-noise ratio and operational stability, maintaining a clear and pure tone even at high gain settings.

[0068] In this embodiment, the power supply module includes a first low-dropout linear stabilizer and a second low-dropout linear stabilizer; the first low-dropout linear stabilizer is used to power the analog audio processing circuit; the second low-dropout linear stabilizer is used to power the digital signal processor; the power supply circuits of the first low-dropout linear stabilizer and the second low-dropout linear stabilizer are isolated from each other.

[0069] Example 1: The power module includes a first low-dropout linear regulator and a second low-dropout linear regulator. The first low-dropout linear regulator uses an AMS1117-5.0 chip to regulate the 7.4V voltage provided by the external battery to +5V, powering analog audio processing circuits (such as operational amplifier circuits based on LM358 or TL072). The second low-dropout linear regulator uses an AMS1117-3.3 chip to regulate the +5V voltage on the system motherboard to +3.3V, powering digital signal processors (such as the main control DSP chip or the Bluetooth module BP1048B2).

[0070] To achieve mutual isolation between the power supply circuits of the first low-dropout linear regulator and the second low-dropout linear regulator, this invention sets up their input and output filter networks (such as electrolytic capacitors and ceramic capacitors) independently in the circuit layout, and adopts a star-shaped single-point grounding strategy, that is, the DC ground of the analog part and the digital part only converge at the power input terminal, thereby effectively cutting off the path of digital power supply noise coupled to the analog circuit through the ground wire.

[0071] Example 2: Based on Example 1, the power module also includes a charge pump chip ICL7660S for generating a negative voltage. The V+ pin of the ICL7660S chip is connected to the +5V voltage output by the first low-dropout linear regulator AMS1117-5.0. A 10μF pump capacitor is connected between its CAP+ and CAP- pins, and its LV pin is grounded. By leaving the OSC pin floating to make it operate at the default frequency, it finally outputs a -5V voltage on its VOUT pin.

[0072] The -5V voltage, together with the +5V voltage generated by the AMS1117-5.0, forms a dual-supply architecture for the dual-supply operational amplifiers (such as the LM358 and TL072) in analog audio processing circuits. The positive power supply pin V+ of the operational amplifier is connected to +5V, and the negative power supply pin V- is connected to -5V, thus providing a total operating voltage range of 10V. This significantly improves the dynamic range of analog audio signal processing and fundamentally eliminates the signal swing limitation and potential distortion caused by the virtual ground midpoint of a single power supply, achieving low-noise, high-fidelity audio amplification.

[0073] In this embodiment, the power module also includes a charge pump chip, which is used to generate a negative voltage; the negative voltage and the positive voltage generated by the first low-dropout linear stabilizer together form a dual power supply architecture for the analog audio processing circuit.

[0074] Example 3: Based on Example 2, the specific implementation of the dual power supply architecture in the power module of the present invention is as follows:

[0075] The charge pump chip (U7) uses an integrated circuit of model ICL7660S; its V+ pin is connected to the +5V voltage output of the first low dropout linear regulator (U4: AMS1117-5.0); its GND pin is grounded; a pump capacitor (C53) is connected between its CAP+ and CAP- pins, and its VOUT pin outputs -5V.

[0076] The -5V voltage, together with the +5V voltage generated by the AMS1117-5.0, powers the dual-supply operational amplifiers (such as IC1A, IC1B, IC2A, IC2B, U9A, U9B) in the analog audio processing circuit, thus forming a complete ±5V dual-supply architecture. Specifically, the positive power supply pin (Vcc+) of the operational amplifier is connected to the +5V network, and the negative power supply pin (Vcc-) is connected to the -5V network.

[0077] This dual-supply architecture provides a ground-referenced symmetrical voltage swing for analog audio signal processing, avoiding the virtual ground bias circuitry required in single-supply designs. This significantly reduces the noise floor and distortion introduced by bias voltage inaccuracies or power supply ripple, providing a solid foundation for high-definition audio processing.

[0078] In this embodiment, the power amplifier is a digital Class-D audio power amplifier that integrates a hardware digital signal processing core.

[0079] Example 4: Based on any of the previous embodiments, the power amplifier of the present invention adopts a digital Class D audio power amplifier, and its specific implementation is as follows:

[0080] The power amplifier uses an integrated circuit (U13) of model ACM8615; this chip integrates a hardware digital signal processing core, stereo differential input, Class D power amplifier driver and various protection circuits;

[0081] Its SDIN, BCLK, and LRCK pins receive I2S audio data streams, bit clocks, and left and right channel clock signals from a digital signal processor (such as a main DSP or Bluetooth module), respectively; its SDA and SCL pins are connected to the system I2C bus for configuring the chip's internal registers, such as setting gain, enabling built-in sound effects, and adjusting equalization parameters; its PVDD pin is connected to the power amplifier stage power supply, and the OUT+ and OUT- pins drive speaker 3 (JP1) after passing through an LC filter network (including inductors L1 and L2 and capacitors C49 and C51);

[0082] The ACM8615 chip, through its built-in hardware DSP core, can efficiently process the received I2S signal directly in the digital domain without requiring extensive calculations from an external main controller, thus greatly reducing system latency and power consumption. Its Class D amplification architecture has high efficiency characteristics, enabling it to drive the speaker 3 to produce a large volume with extremely low heat loss, thereby solving the shortcomings of insufficient power and severe heat generation in traditional built-in solutions.

[0083] In this embodiment, a digital signal processor is used for a motion howling suppression algorithm. The howling suppression algorithm includes: performing frame segmentation and fast Fourier transform on the input digital audio signal to obtain a frequency domain signal; analyzing the energy change rate of each frequency point in the frequency domain signal; identifying frequency points whose energy change rate exceeds a preset threshold as potential howling frequency points; generating a digital notch filter corresponding to the potential howling frequency point and attenuating the frequency point.

[0084] Example 5: Based on any of the previous embodiments, the specific implementation of the howling suppression algorithm by the digital signal processor of the present invention is as follows:

[0085] The digital signal processor (such as the processing unit in the main DSP chip or the Bluetooth module BP1048B2) performs howling suppression processing on the input digital audio signal frame by frame; for a sampling rate of 44.1kHz, each frame length is taken as 1024 points or 2048 points for Fast Fourier Transform (FFT), and a 50% overlap rate is set between frames to balance frequency resolution and time response speed.

[0086] After the frequency domain signal is obtained by transformation, the algorithm calculates and analyzes the rate of change of energy at each frequency point compared to the previous frame; when the rate of change of energy at a certain frequency point exceeds the threshold slope set according to experience or system environment, the frequency point is determined to be a potential howling frequency point.

[0087] Subsequently, the algorithm dynamically generates a digital notch filter for the target frequency. This filter is implemented using an IIR or FIR structure, with its quality factor Q set in the range of tens to hundreds to ensure concentrated and deep attenuation of the target howling frequency while minimizing the impact on adjacent normal timbre frequencies. The attenuation amplitude and filter duration are adaptively adjusted according to the amplitude and duration of the energy rise at the target frequency.

[0088] This algorithm updates the frequency information to be suppressed in each frame and forms a closed-loop control with the FFT analysis module to achieve fast, accurate and dynamic suppression of howling signals. Its overall response time can be shortened to less than 5 milliseconds, thus effectively ensuring the real-time performance and stability of the system.

[0089] In this embodiment, the digital signal processor is also used to implement at least one digital sound effect among reverb, delay, and chorus;

[0090] Example 6: Based on Example 5, the digital signal processor of the present invention implements various digital sound effects in the following specific ways:

[0091] The digital signal processor is the BP1048B2 audio processing chip (U1) manufactured by Mountain View Technologies. This chip has a built-in high-performance DSP core and a matching audio effect algorithm library.

[0092] When the system is working, in addition to running the howling suppression algorithm as described in Example 5, the chip also calls its internally embedded sound effect algorithm program to process the audio data stream in parallel. The sound effect algorithm includes at least reverb and delay. Users can send commands through an external controller (such as an MCU) to configure the BP1048B2 chip via the I2C or UART interface, select to turn on or off specific sound effects, and adjust their parameters (such as reverb time and delay feedback).

[0093] Therefore, without adding extra hardware circuitry, the system can achieve high-quality digital sound processing and feedback suppression through a single chip, greatly enriching the tonal expressiveness of the electric guitar while ensuring system integration and cost-effectiveness.

[0094] In this embodiment, the control motherboard also integrates a Bluetooth audio receiving module, which receives external audio data and transmits it to a digital signal processor for processing.

[0095] Example 7: Based on any of the previous embodiments, the specific implementation of the Bluetooth audio receiving module of the present invention is as follows:

[0096] The control motherboard integrates a Bluetooth audio receiver module, the core of which uses Mountainview's BP1048B2 chip (U1); this chip integrates a Bluetooth controller, RF transceiver, audio codec, and digital signal processor.

[0097] The BP1048B2 chip is connected to the onboard antenna (E1) via its RFIO pin to receive Bluetooth audio data streams from external smart devices (such as mobile phones and tablets). The received audio data is decoded internally by the chip and converted into digital audio signals in I2S format (including I2S_BCLK, I2S_LRCK, and I2S_DO0).

[0098] The I2S signal is directly transmitted to the system's digital signal processor (which can be the chip's own DSP core or another main DSP chip in the system) for subsequent processing such as howling suppression and sound mixing. This enables the function of mixing external audio with the pickup signal from the electric guitar itself, greatly expanding the application scenarios of the electric guitar and making it convenient for users to play accompaniment or practice along.

[0099] In this embodiment, the analog audio processing circuit includes a distortion effect circuit, which includes a soft clipping circuit composed of an operational amplifier and diodes.

[0100] Example 8: Based on any of the previous embodiments, the specific implementation of the distortion effect circuit in the simulated audio processing circuit of the present invention is as follows:

[0101] The distortion effect circuit is located in the analog audio processing link. Its core uses at least one operational amplifier (such as IC2A:LM358) and a pair of anti-parallel diodes (D3, D4:1N4148) to form a soft clipping circuit.

[0102] The circuit design references the classic structure of the Ibanez TS808 overdrive effects circuit to achieve a smooth clipping effect and a prominent midrange tone. Specifically, the operational amplifier is connected as a non-inverting amplifier circuit, and its output is connected to a soft clipping network composed of diodes (D3, D4) through a coupling capacitor (C63: 1μF); this network is connected in parallel between the operational amplifier output and ground, or embedded in the negative feedback loop.

[0103] When the amplitude of the input audio signal is low, the diode is in the off state and does not work, and the circuit operates in linear amplification mode; when the amplitude of the input signal increases to exceed the conduction threshold of the diode, the diode begins to conduct alternately, smoothly clipping the positive and negative peaks of the signal, thereby generating warm and natural overload harmonics, and through the optimization of the parameters of the surrounding resistor (R42: 500R) and capacitor (C57: 3.9nF), the mid-frequency band is emphasized.

[0104] This analog distortion circuit provides the basic overload tone for the entire system. It produces rich harmonics with low noise levels. Combined with the digital audio processing of the subsequent stage, it forms a comprehensive audio system with rich layers and excellent sound quality.

[0105] In this embodiment, the electric guitar body 1 is provided with an acoustic cavity 2 for mounting a speaker 3. The inner wall of the acoustic cavity 2 is provided with sound-absorbing material, and its structure is designed to enhance the guidance and response of low-frequency sound waves.

[0106] Example 9: Based on any of the previous embodiments, the specific design and function of the acoustic cavity 2 inside the electric guitar body 1 of the present invention are as follows:

[0107] The electric guitar body 1 has a dedicated acoustic cavity 2 for mounting the speaker 3. This cavity is not a simple storage space, but is specially designed for acoustics.

[0108] The inner wall of the acoustic cavity 2 is lined with sound-absorbing material (such as polyester fiber cotton or acoustic foam); this material is used to absorb the sound wave energy in the mid-to-high frequency range, and can effectively attenuate the high frequency components that may be transmitted to the microphone after multiple reflections in the cavity, thereby cutting off the acoustic feedback loop from the physical transmission path and reducing the probability of high frequency howling.

[0109] Meanwhile, the physical structure of the cavity (such as its volume, internal geometry, and the position of the sound outlet) is designed to enhance the guidance and response of low-frequency sound waves; this structure forms a Helmholtz resonant cavity or a similar highly compliant acoustic guiding structure, which can effectively guide and enhance the sound waves radiated backward by the speaker 3, especially to compensate and extend the low-frequency range, so that even a small speaker 3 can obtain a fuller and thicker low-frequency sound effect;

[0110] The acoustic cavity design, which combines high-frequency absorption and low-frequency enhancement, optimizes the overall tonal balance while suppressing feedback, achieving the dual benefits of reducing self-excitation and improving sound quality.

[0111] Example 10: This example details a method for suppressing howling in an electric guitar. This method is applied to the digital signal processor of any of the aforementioned example systems; the method includes the following steps:

[0112] S1. Receive digitized audio signals:

[0113] Digital signal processors (such as the BP1048B2 or the main DSP chip) receive digital audio signal streams from analog-to-digital converters, typically at a sampling rate of 44.1 kHz or 48 kHz.

[0114] S2. Perform frame segmentation and time-frequency transformation on the audio signal to obtain spectral information:

[0115] The processor divides the received audio data stream into frames; for a sampling rate of 44.1kHz, each frame is 1024 or 2048 points long; a 50% overlap rate is used between frames to balance frequency resolution and time resolution; then, a Fast Fourier Transform (FFT) is applied to each frame of data to convert the time-domain signal into a frequency-domain signal, obtaining a spectrum containing amplitude and phase information of each frequency point;

[0116] S3. Analyze the spectral information to identify frequency points where energy rises abnormally rapidly:

[0117] The algorithm calculates the energy value of each frequency point in the current frame spectrum and compares it with the energy value of the corresponding frequency point in the previous frame to calculate its energy change rate; the system sets a threshold slope for the energy change rate; when the energy change rate of a frequency point exceeds the preset threshold, the frequency point is determined to be a potential howling frequency point with abnormally rapid energy increase.

[0118] S4. Generate a digital filter to selectively attenuate frequency points:

[0119] Once a potential howling frequency is identified, a pre-defined algorithm immediately and dynamically generates a digital notch filter for that frequency. The center frequency of this filter is aligned with the identified howling frequency, and its quality factor Q is set in the range of tens to hundreds to achieve concentrated and deep attenuation of the target frequency while minimizing the impact on adjacent normal frequency components. This filter can be implemented using an IIR or FIR structure, and the attenuation depth can be adaptively adjusted according to the energy rise of the frequency.

[0120] S5. Output the attenuated audio signal:

[0121] The frame data processed by the digital notch filter is superimposed and added with subsequent frames to reconstruct a continuous time-domain signal, which is then output to the digital-to-analog converter or subsequent audio processing module.

[0122] By continuously and in real-time analyzing and processing each frame of signal, a fast closed-loop control is formed, which can suppress howling in a timely manner and ensure the stability and sound quality of the system.

[0123] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0124] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A comprehensive intelligent electric guitar anti-feedback and anti-self-oscillation system, characterized in that, include: The control board, speakers, and power modules that supply power to each unit are located inside the electric guitar body; The control motherboard integrates an audio processing unit, which includes an analog audio processing circuit, a digital signal processor, and a power amplifier. The system receives the analog signal from the electric guitar pickup through the audio processing unit, and outputs it to the power amplifier after analog-to-digital conversion, digital sound effect processing, feedback suppression processing, and digital-to-analog conversion. The power amplifier drives the speaker to produce sound; The speaker is suspended and fixed to the electric guitar body by a shock-absorbing structure, and there is no rigid connection between the speaker and the electric guitar body.

2. The intelligent electric guitar anti-feedback and anti-self-oscillation integrated system according to claim 1, characterized in that, The power module includes a first low-dropout linear stabilizer and a second low-dropout linear stabilizer; The first low-dropout linear stabilizer is used to power the analog audio processing circuit; The second low-dropout linear stabilizer is used to power the digital signal processor; The power supply circuits of the first low-dropout linear stabilizer and the second low-dropout linear stabilizer are isolated from each other.

3. The intelligent electric guitar anti-feedback and anti-self-oscillation integrated system according to claim 2, characterized in that, The power module also includes a charge pump chip, which is used to generate a negative voltage; The negative voltage and the positive voltage generated by the first low-dropout linear stabilizer together form a dual-power supply architecture for the analog audio processing circuit.

4. The intelligent electric guitar anti-feedback and anti-self-oscillation integrated system according to claim 1, characterized in that, The power amplifier is a digital Class-D audio power amplifier that integrates a hardware digital signal processing core.

5. The intelligent electric guitar anti-feedback and anti-self-oscillation integrated system according to claim 1, characterized in that, The digital signal processor is used for a motion howling suppression algorithm, which includes: The input digital audio signal is framed and subjected to Fast Fourier Transform to obtain the frequency domain signal; Analyze the rate of energy change at each frequency point in the frequency domain signal; The frequency points with energy change rates set to a preset threshold are identified as potential howling frequencies; A digital notch filter corresponding to the potential howling frequency is generated and attenuated at that frequency.

6. A comprehensive intelligent electric guitar anti-feedback and anti-self-oscillation system according to claim 1 or 5, characterized in that, The digital signal processor is also used to implement at least one digital sound effect among reverb, delay, and chorus.

7. The intelligent electric guitar anti-feedback and anti-self-oscillation integrated system according to claim 1, characterized in that, The control motherboard also integrates a Bluetooth audio receiving module, which receives external audio data and transmits it to the digital signal processor for processing.

8. The intelligent electric guitar anti-feedback and anti-self-oscillation integrated system according to claim 1, characterized in that, The analog audio processing circuit includes a distortion effect circuit, which comprises a soft clipping circuit consisting of an operational amplifier and diodes.

9. The intelligent electric guitar anti-feedback and anti-self-oscillation integrated system according to claim 1, characterized in that, The electric guitar body has an acoustic cavity for mounting the speaker. The inner wall of the acoustic cavity is provided with sound-absorbing material, and its structure is designed to enhance the guidance and response of low-frequency sound waves.

10. A method for suppressing howling in an electric guitar, characterized in that, The digital signal processor applied to the intelligent electric guitar anti-feedback and anti-self-oscillation integrated system according to any one of claims 1 to 9 includes the following steps: S1. Receives digitized audio signals; S2. The audio signal is framed and time-frequency transformed to obtain spectral information; S3. Analyze the spectrum information to identify frequency points where energy rises abnormally and rapidly; S4. Generate a digital filter to selectively attenuate the frequency points; S5. Outputs the attenuated audio signal.

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