Oscilloscope automatic trigger circuit based on sound detection

By using an oscilloscope automatic triggering circuit based on sound detection, the problems of inability to respond to sudden faults in real time and poor compatibility in existing technologies are solved. It realizes the oscilloscope triggering function with automatic identification and fast response, is compatible with mainstream oscilloscopes, and reduces the false triggering rate.

CN224247148UActive Publication Date: 2026-05-15HUANGSHAN DOART-ENERGY TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
HUANGSHAN DOART-ENERGY TECH CO LTD
Filing Date
2025-07-21
Publication Date
2026-05-15

AI Technical Summary

Technical Problem

In the existing technology, the oscilloscope's automatic trigger circuit cannot respond in real time to sudden faults, such as the microsecond-level acoustic pulses of a power supply failure, and has poor compatibility, cannot be adapted to electronic devices, relies on physical buttons for manual triggering, and cannot automatically identify acoustic characteristics.

Method used

An oscilloscope automatic trigger circuit based on sound detection was designed, including a sound pickup circuit, a signal amplification circuit, a bandpass filter circuit, a signal trigger circuit, and a signal output circuit. By picking up ambient sound, amplifying, filtering, and triggering the signal, a trigger signal for the oscilloscope is generated.

Benefits of technology

It achieves automatic identification of acoustic characteristics at the time of explosion, reduces false triggering rate, supports high-voltage scenarios, has good compatibility, is compatible with mainstream oscilloscopes, has fast response speed, and ensures capture of the waveform at the start of the explosion.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model discloses an oscilloscope automatic trigger circuit based on sound detection, which comprises a sound pickup circuit, a signal amplification circuit, a band-pass filter circuit, a signal trigger circuit, a signal output circuit, an oscilloscope and a power supply Vcc, the signal amplification circuit is connected with the sound pickup circuit and used for operational amplification of sound signals, the band-pass filter circuit is connected with the signal amplification circuit and used for filtering the sound signals amplified by the signal amplification circuit and filtering useful signals, and the signal trigger circuit is connected with the band-pass filter circuit. The signal trigger circuit is used for monitoring whether the filtered useful signals exceed a set threshold value or not in real time, the signal output circuit is connected with the signal trigger circuit and used for outputting trigger signals, and the oscilloscope is connected with the signal output circuit and used for receiving the trigger signals and starting and displaying waveforms. The utility model has the advantages of automatic identification, good compatibility and the like.
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Description

Technical Field

[0001] This utility model belongs to the field of oscilloscope automatic trigger circuit technology, specifically relating to an oscilloscope automatic trigger circuit based on sound detection. Background Technology

[0002] When developing and debugging power supplies, there is a high probability of encountering situations such as power failure. Capturing the waveform at the time of the power failure can greatly improve the efficiency of fault analysis. In the existing technology, the main method is to manually press a button after the power failure to capture the waveform. This is obviously not fast enough, and there is also the problem of not knowing the triggering conditions when setting the waveform trigger.

[0003] For example, patent application number 202110454857 discloses a special equipment explosion test synchronous triggering device, including a main housing and two trigger connection cables. The main housing is provided with a trigger signal interface I, a trigger signal interface II, a power interface and a trigger button. The trigger connection cable includes a connecting cable and trigger connectors and connectors connected to its two ends. A high-speed camera is connected to the trigger signal interface I through the trigger connection cable, and the firing gun is connected to the trigger signal interface II through the other trigger connection cable. An intermediate relay is provided inside the main housing, and the output end of the intermediate relay is connected to the trigger signal interface I and the trigger signal interface II respectively. The application scenarios of this special equipment's explosion test synchronous triggering device are limited. It only supports mechanical triggering and cannot be adapted to the explosion of electronic equipment, such as acoustic feature recognition when the power supply is short-circuited. Moreover, its triggering conditions are rigid, and it relies on manual triggering with a physical button, so it cannot respond to sudden faults in real time, such as the microsecond-level acoustic pulse of a power supply explosion. This equipment's explosion test synchronous triggering device also has poor compatibility. Its output interface is only compatible with high-speed cameras and transmitter guns, and it does not integrate electrical standards such as BNC / TTL levels for oscilloscope EXTTRIG interfaces. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides an oscilloscope automatic triggering circuit based on sound detection that can automatically identify and has good compatibility.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] An oscilloscope auto-trigger circuit based on sound detection includes:

[0007] Sound pickup circuitry, used to pick up ambient sound;

[0008] The signal amplification circuit is connected to the sound pickup circuit and is used to amplify the sound signal using an operational amplifier.

[0009] A bandpass filter circuit is connected to a signal amplifier circuit and is used to filter the audio signal amplified by the operational amplifier of the signal amplifier circuit and filter out the useful signal.

[0010] The signal triggering circuit is connected to the bandpass filter circuit. The signal triggering circuit is used to monitor in real time whether the filtered useful signal exceeds the set threshold.

[0011] The signal output circuit is connected to the signal triggering circuit and is used to output the trigger signal.

[0012] An oscilloscope, connected to a signal output circuit, is used to receive trigger signals and start displaying waveforms.

[0013] The power supply Vcc is connected to the sound pickup circuit, signal amplification circuit, bandpass filter circuit, signal triggering circuit, and signal output circuit, respectively. The power supply Vcc is used to supply power.

[0014] Preferably, the sound pickup circuit includes an electret microphone DS1, resistors R1, R2, R8, and R14, capacitors C5 and C8. One end of the electret microphone DS1 is connected to one end of R1, and the other end of R1 is connected to the power supply VCC. The other end of the electret microphone DS1 is grounded. One end of R14 is grounded, and the other end of R14 is connected to one end of R2. The other end of R2 is connected to the power supply VCC. One end of capacitor C5 is connected to the connection point between the electret microphone DS1 and R1, and the other end of capacitor C5 is connected to one end of resistor R8. One end of capacitor C8 is connected to the connection point between R2 and R14, and the other end of capacitor C8 is grounded.

[0015] Preferably, the signal amplification circuit includes an operational amplifier U1B and a resistor R12. The other end of the resistor R8 and one end of the resistor R12 are both connected to the inverting input terminal of the operational amplifier U1B. The non-inverting input terminal of the operational amplifier U1B is connected to the junction of the resistors R2 and R14. The other end of the resistor R12 is connected to the output terminal of the operational amplifier U1B.

[0016] Preferably, the bandpass filter circuit includes an operational amplifier U1A, resistors R5, R6, R10, R13, capacitors C3, C4, and C6. One end of resistor R6 is connected to the output terminal of operational amplifier U1A, and the other end of resistor R6 is connected to one end of resistor R5, one end of capacitor C4, and one end of capacitor C6. The other end of resistor R5 is connected to the output terminal of operational amplifier U1A. The other end of capacitor C4 is connected to the non-inverting input terminal of operational amplifier U1A, and the other end of capacitor C6 is grounded. One end of resistor R10 is connected to the connection point of capacitor C4 and the non-inverting input terminal of operational amplifier U1A, and the other end of resistor R10 is grounded. One end of capacitor C3 is connected to the positive power supply terminal of operational amplifier U1A, and the other end of capacitor C3 is grounded. One end of resistor R13 is connected to the inverting input terminal of operational amplifier U1A, and the other end of resistor R13 is connected to the output terminal of operational amplifier U1A. The positive power supply terminal of operational amplifier U1A is connected to the power supply Vcc, and the negative power supply terminal of operational amplifier U1A is grounded.

[0017] Preferably, the signal triggering circuit includes operational amplifier U2A, operational amplifier U2B, resistors R3, R4, R9, R11, R15, capacitors C1, C2, and C9. One end of resistor R9 is connected to the output terminal of operational amplifier U1A, and the other end of resistor R9 is connected to the inverting input terminal of operational amplifier U2A. One end of resistor R3 is connected to the power supply Vcc, and the other end of resistor R3 is connected to one end of resistor R11. The other end of resistor R11 is connected to one end of resistor R15, and the other end of resistor R15 is grounded. One end of capacitor C2 is connected to the power supply Vcc, and the other end of capacitor C2 is connected to the operational amplifier U2B. The non-inverting input terminal of operational amplifier U2A is connected to the ground. One end of capacitor C1 is connected to the positive power supply terminal of operational amplifier U2A, and the other end of capacitor C1 is grounded. One end of capacitor C9 is connected to the inverting input terminal of operational amplifier U2B, and the other end of capacitor C9 is grounded. One end of resistor R4 is connected to the power supply Vcc, and the other end of resistor R4 is connected to the output terminal of operational amplifier U2A. The positive power supply terminal of operational amplifier U2A is connected to the power supply Vcc. The inverting input terminal of operational amplifier U2A is connected to the non-inverting input terminal of operational amplifier U2B. The negative power supply terminal of operational amplifier U2A is grounded. The output terminal of operational amplifier U2B is connected to the output terminal of operational amplifier U2A.

[0018] Preferably, the signal output circuit includes a resistor R7, a capacitor C7, a BNC connector P1, and a transient voltage suppressor diode TVS1. One end of the resistor R7 is connected to the output terminal of the operational amplifier U2A, and the other end of the resistor R7 is connected to one end of the capacitor C7, one end of the BNC connector P1, and one end of the transient voltage suppressor diode TVS1, respectively. The other ends of the capacitor C7, the BNC connector P1, and the transient voltage suppressor diode TVS1 are all grounded.

[0019] By adopting the above technical solution, this utility model has the following beneficial effects:

[0020] This invention can capture the sound waves during an explosion, convert them into electrical signals, and then generate trigger pulses through filtering and amplification. The oscilloscope captures and displays the waveforms. Compared with existing technologies, which rely on physical buttons for manual triggering, lack isolation, use relays for direct conduction, and require customized interfaces, this invention automatically identifies acoustic features, filters out environmental noise through bandpass filtering, adopts a multi-level confirmation mechanism to reduce false triggering rates, and uses isolated power supply to support high-voltage scenarios. The BNC connector P1 is compatible with mainstream oscilloscopes, providing good compatibility.

[0021] In summary, this utility model has advantages such as automatic identification and good compatibility. Attached Figure Description

[0022] Figure 1 This is a block diagram of the modules of this utility model;

[0023] Figure 2 This is a partial circuit diagram of this utility model;

[0024] Figure 3 This is another part of the circuit schematic diagram of this utility model;

[0025] Figure 4 This is the circuit diagram of the power supply of this utility model. Detailed Implementation

[0026] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.

[0027] The components of the present invention embodiments described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0028] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0029] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," 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 utility model and simplifying the description, and do not 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 utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 utility model based on the specific circumstances.

[0031] Example 1

[0032] In this embodiment, an oscilloscope automatic triggering circuit based on sound detection is proposed. This circuit automatically triggers when an oscilloscope crashes, capturing and displaying the waveform. This invention features fast response and low triggering delay, unlike existing technologies that rely on manual triggering, which is slow. This invention ensures the capture of the waveform at the start of the crash. Furthermore, this invention offers a safety breakthrough; the isolated power supply design completely solves the problem of short circuits on construction sites, preventing secondary crashes.

[0033] like Figures 1-4As shown in one embodiment of this utility model, the oscilloscope automatic trigger circuit based on sound detection includes a sound pickup circuit, a signal amplification circuit, a bandpass filter circuit, a signal trigger circuit, a signal output circuit, an oscilloscope, and a power supply Vcc. The sound pickup circuit is used to pick up ambient sound. The signal amplification circuit is connected to the sound pickup circuit and is used to amplify the sound signal using an operational amplifier. This utility model can use a high-sensitivity silicon microphone to pick up ambient sound in real time, and then amplify it using an operational amplifier to obtain a useful signal. The sound pickup circuit converts the sound signal into a weak electrical signal, provides a microphone bias voltage, and isolates DC while coupling AC signals. The signal amplification circuit amplifies the weak electrical signal output by the sound pickup module and adjusts the amplification gain through negative feedback. The bandpass filter circuit is connected to the signal amplification circuit and is used to filter the sound signal amplified by the operational amplifier in the signal amplification circuit, filtering out the useful signal. The bandpass filter circuit filters out the useful signal (frequency band: 100Hz–5kHz) from the amplified sound signal, removing irrelevant frequency components (such as low-frequency noise and high-frequency interference) from the signal and retaining the target frequency. The sound signal within the range is triggered by a signal triggering circuit connected to a bandpass filter circuit. The signal triggering circuit is used to monitor in real time whether the filtered useful signal exceeds the set threshold. The signal output circuit is connected to the signal triggering circuit and is used to output the trigger signal. The signal triggering circuit detects in real time whether the filtered signal exceeds the set threshold. If it does, it generates an EXTRIG trigger signal (falling edge valid). The signal triggering circuit compares the filtered signal with the reference voltage and generates a pulse signal that meets the triggering requirements of the oscilloscope. The signal output circuit transmits the trigger signal safely and stably to the oscilloscope, protecting the circuit from damage by transient high voltage. The oscilloscope is connected to the signal output circuit and is used to receive the trigger signal and start displaying the waveform. The power supply Vcc is connected to the sound pickup circuit, signal amplification circuit, bandpass filter circuit, signal triggering circuit, and signal output circuit respectively. The power supply Vcc is used for power supply. In this application, the power supply Vcc is powered by two 3V 2032 button batteries to ensure isolation. The power supply Vcc is also connected to a switch S1, which can be used to ensure the power supply is switched on and off. The power supply Vcc provides a stable DC power supply to each module and filters out power supply noise.

[0034] When using this invention, the sound sensor (sound pickup circuit) is fixed within 30cm of the power supply under test, and the signal output circuit is connected to the EXTTRIG interface of the oscilloscope. The specific triggering process is as follows: when the power supply under test crashes, the sound sensor (sound pickup circuit) detects the sound pressure pulse. The signal triggering circuit of this invention confirms that the spectral energy is concentrated at a specific frequency and that the signal exceeds the threshold, and then generates a pulse (that is, outputs a trigger signal). The oscilloscope starts to capture the waveform at the time of the crash. The oscilloscope's EXTTRIG interface is the external trigger interface of the oscilloscope, usually a BNC or TSV interface.

[0035] Specific reference Figures 2-4 The sound pickup circuit of this utility model includes an electret microphone DS1, resistors R1, R2, R8, and R14, capacitors C5 and C8. One end of the electret microphone DS1 is connected to one end of R1, and the other end of R1 is connected to the power supply VCC. The other end of the electret microphone DS1 is grounded. One end of R14 is grounded, and the other end of R14 is connected to one end of R2. The other end of R2 is connected to the power supply VCC. One end of capacitor C5 is connected to the connection point between the electret microphone DS1 and R1, and the other end of capacitor C5 is connected to one end of resistor R8. One end of capacitor C8 is connected to the connection point between R2 and R14, and the other end of capacitor C8 is grounded.

[0036] The signal amplification circuit includes an operational amplifier U1B and a resistor R12. The other end of the resistor R8 and one end of the resistor R12 are both connected to the inverting input terminal of the operational amplifier U1B. The non-inverting input terminal of the operational amplifier U1B is connected to the junction of the resistors R2 and R14. The other end of the resistor R12 is connected to the output terminal of the operational amplifier U1B.

[0037] Please continue to refer to Figures 2-4 The bandpass filter circuit of this utility model includes an operational amplifier U1A, resistors R5, R6, R10, R13, capacitors C3, C4, and C6. One end of resistor R6 is connected to the output terminal of operational amplifier U1A, and the other end of resistor R6 is connected to one end of resistor R5, one end of capacitor C4, and one end of capacitor C6. The other end of resistor R5 is connected to the output terminal of operational amplifier U1A. The other end of capacitor C4 is connected to the non-inverting input terminal of operational amplifier U1A. The other end of capacitor C6 is grounded. One end of resistor R10 is connected to the connection point of capacitor C4 and the non-inverting input terminal of operational amplifier U1A. The other end of resistor R10 is grounded. One end of capacitor C3 is connected to the positive power supply terminal of operational amplifier U1A. The other end of capacitor C3 is grounded. One end of resistor R13 is connected to the inverting input terminal of operational amplifier U1A. The other end of resistor R13 is connected to the output terminal of operational amplifier U1A. The positive power supply terminal of operational amplifier U1A is connected to the power supply Vcc, and the negative power supply terminal of operational amplifier U1A is grounded.

[0038] The signal triggering circuit includes operational amplifiers U2A and U2B, resistors R3, R4, R9, R11, R15, capacitors C1, C2, and C9. One end of resistor R9 is connected to the output of operational amplifier U1A, and the other end is connected to the inverting input of operational amplifier U2A. One end of resistor R3 is connected to the power supply Vcc, and the other end is connected to one end of resistor R11. The other end of resistor R11 is connected to one end of resistor R15, and the other end of resistor R15 is grounded. One end of capacitor C2 is connected to the power supply Vcc, and the other end is connected to operational amplifier U2A. The non-inverting input terminal of operational amplifier U2A is connected to the terminal of operational amplifier U2A. One end of capacitor C1 is connected to the positive power supply terminal of operational amplifier U2A, and the other end of capacitor C1 is grounded. One end of capacitor C9 is connected to the inverting input terminal of operational amplifier U2B, and the other end of capacitor C9 is grounded. One end of resistor R4 is connected to the power supply Vcc, and the other end of resistor R4 is connected to the output terminal of operational amplifier U2A. The positive power supply terminal of operational amplifier U2A is connected to the power supply Vcc. The inverting input terminal of operational amplifier U2A is connected to the non-inverting input terminal of operational amplifier U2B. The negative power supply terminal of operational amplifier U2A is grounded. The output terminal of operational amplifier U2B is connected to the output terminal of operational amplifier U2A.

[0039] Finally, the signal output circuit of this utility model includes a resistor R7, a capacitor C7, a BNC connector P1, and a transient voltage suppression diode TVS1. One end of the resistor R7 is connected to the output terminal of the operational amplifier U2A, and the other end of the resistor R7 is connected to one end of the capacitor C7, one end of the BNC connector P1, and one end of the transient voltage suppression diode TVS1. The other ends of the capacitor C7, the BNC connector P1, and the transient voltage suppression diode TVS1 are all grounded.

[0040] This utility model is used near the R&D and debugging power supply to capture waveforms during a crash. The overall signal flow of this utility model follows the path of "sound signal to electrical signal to amplified signal to signal filtering to signal triggering and finally signal output". The specific steps are as follows:

[0041] Step 1: The sound pickup circuit is mainly used to convert sound signals into electrical signals.

[0042] Signal input: External sound is converted into a weak alternating electrical signal through the electret microphone DS1 (the specific steps can be sound vibration to diaphragm vibration, then capacitance change, and then electrical signal change).

[0043] Bias power supply: The power supply VCC provides the working voltage to the electret microphone DS1 through resistor R1, ensuring that the electret microphone DS1 works normally. Resistors R2 and R14 form a voltage divider circuit to provide a stable bias voltage to the output terminal of the electret microphone DS1, so that the electrical signal fluctuates within a reasonable range.

[0044] Signal coupling: The alternating electrical signal (superimposed with DC bias) output by the electret microphone DS1 is isolated from the DC component by capacitor C5, retaining only the AC signal. After being current-limited by resistor R8, it is transmitted to the input terminal of the signal amplification circuit.

[0045] Auxiliary filtering: Capacitor C8 is connected between the voltage divider point of resistors R2 and R14 and ground to filter out noise in the bias voltage and stabilize the operating point of the electret microphone DS1.

[0046] Step 2: The signal amplification circuit can amplify weak electrical signals.

[0047] Signal input: The AC signal from the sound pickup circuit is input to the inverting input of the operational amplifier U1B;

[0048] Amplification principle: The non-inverting input of operational amplifier U1B is connected to the voltage divider point of resistors R2 and R14 (to obtain a stable bias). The inverting input and output of operational amplifier U1B are connected by resistor R12 to form a negative feedback circuit. The amplification gain can be set by adjusting the resistance value of resistor R12 to achieve precise amplification of weak signals.

[0049] Signal output: The amplified signal is transmitted from the output of operational amplifier U1B to the bandpass filter circuit.

[0050] Step 3: A bandpass filter circuit is used to filter the target frequency signal.

[0051] Signal input: The amplified signal is connected to the non-inverting input terminal of operational amplifier U1A;

[0052] Filtering principle: The non-inverting input of operational amplifier U1A is biased by a voltage divider formed by resistors R5 and R6, and receives the input signal through capacitor C4. Together with capacitor C6 and resistor R10, it forms an RC bandpass filter network that allows only signals within a specific frequency range to pass through. The inverting input of operational amplifier U1A is connected to the output of operational amplifier U1A through resistor R13, forming negative feedback and stabilizing the filtering characteristics.

[0053] Power supply filtering: Capacitor C3 is connected between the power supply terminal of operational amplifier U1A and ground to filter out power supply noise and ensure stable operation of operational amplifier U1A;

[0054] Signal output: The filtered clean signal is transmitted from the output of operational amplifier U1A to the signal trigger circuit.

[0055] Step 4: The signal triggering circuit is used to generate the trigger pulse signal.

[0056] First-stage comparison (operational amplifier U2A): The bandpass filtered signal is current-limited by resistor R9 and then connected to the inverting input of operational amplifier U2A. The non-inverting input of operational amplifier U2A is connected to power supply VCC through resistor R3, forming a voltage divider circuit to provide reference voltage Vref1. When the input signal voltage is higher than Vref1, operational amplifier U2A outputs a high level, and vice versa, thus realizing the initial threshold judgment of the signal.

[0057] Second-stage comparator (operational amplifier U2B): The output signal of operational amplifier U2A is connected to the inverting input of operational amplifier U2B. The non-inverting input of operational amplifier U2B is connected to the power supply VCC through resistor R11 and grounded through resistor R15, forming a voltage divider circuit to provide a reference voltage Vref2. The signal is further shaped through two-stage comparator to ensure the stability of the trigger pulse.

[0058] Auxiliary stabilization: Capacitor C2 is connected to the non-inverting input terminal of operational amplifier U2A, capacitor C9 is connected to the inverting input terminal of operational amplifier U2B and ground to filter out reference voltage noise, and capacitor C1 is connected to the positive power supply terminal of operational amplifier U2A and ground to stabilize the power supply.

[0059] Signal output: The shaped trigger signal is transmitted from the output terminal of operational amplifier U2B to the trigger signal output circuit.

[0060] Step 5: The signal output circuit performs signal adaptation and protection.

[0061] Signal transmission: After the trigger signal is current-limited by resistor R7, it is connected to the center pin of BNC connector P1 and output to the EXT-TRIG interface of the oscilloscope;

[0062] Protection and Filtering: Transient voltage suppressor diode TVS1 is connected in parallel between the center pin of BNC connector P1 and ground to absorb external transient high voltage (such as electrostatic discharge) and protect the oscilloscope interface. Capacitor C7 is connected in parallel between the center pin of BNC connector P1 and ground to filter out high-frequency glitches and ensure the purity of the output signal.

[0063] Grounding: The shell of BNC connector P1 is grounded to avoid interference signal coupling.

[0064] Step 6: Power Module – Global Power Supply and Stability

[0065] The power supply VCC supplies power to all active devices (electret microphone DS1, operational amplifiers U1A / U1B / U2A / U2B), and filters out ripple through capacitors C1, C3 and other filter capacitors to ensure that each module works under a stable voltage. All ground (GND) pins share a common ground, forming a current loop.

[0066] Therefore, the overall signal flow in this application is as follows: sound to electret microphone DS1 (electrical signal conversion), then to capacitor C5 (AC coupling), then to resistor R8, then to operational amplifier U1B (amplification), then to operational amplifier U1A (bandpass filtering), then to resistor R9, then to operational amplifier U2A (first-stage comparator), then to operational amplifier U2B (second-stage comparator), then to resistor R7, then to BNC connector P1 (trigger output), and finally to the oscilloscope EXT-TRIG. The entire circuit achieves precise conversion of the sound signal to the oscilloscope trigger signal through cascaded processing from "pickup to amplification to filtering to triggering to output." Its core advantage lies in ensuring the stability and reliability of the trigger signal through modular optimization (such as adjustable gain, bandpass filtering, and two-stage triggering).

[0067] This embodiment does not impose any limitation on the shape, material, structure, etc. of this utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this utility model shall fall within the protection scope of this utility model.

Claims

1. An oscilloscope automatic triggering circuit based on sound detection, characterized in that, include: Sound pickup circuitry, used to pick up ambient sound; The signal amplification circuit is connected to the sound pickup circuit and is used to amplify the sound signal using an operational amplifier. A bandpass filter circuit is connected to a signal amplifier circuit and is used to filter the audio signal amplified by the operational amplifier of the signal amplifier circuit and filter out the useful signal. The signal triggering circuit is connected to the bandpass filter circuit. The signal triggering circuit is used to monitor in real time whether the filtered useful signal exceeds the set threshold. The signal output circuit is connected to the signal triggering circuit and is used to output the trigger signal. An oscilloscope, connected to a signal output circuit, is used to receive trigger signals and start displaying waveforms. The power supply Vcc is connected to the sound pickup circuit, signal amplification circuit, bandpass filter circuit, signal triggering circuit, and signal output circuit, respectively. The power supply Vcc is used to supply power.

2. The oscilloscope automatic triggering circuit based on sound detection according to claim 1, characterized in that: The sound pickup circuit includes an electret microphone DS1, resistors R1, R2, R8, and R14, capacitors C5 and C8. One end of the electret microphone DS1 is connected to one end of R1, and the other end of R1 is connected to the power supply VCC. The other end of the electret microphone DS1 is grounded. One end of R14 is grounded, and the other end of R14 is connected to one end of R2. The other end of R2 is connected to the power supply VCC. One end of capacitor C5 is connected to the connection point between the electret microphone DS1 and R1, and the other end of capacitor C5 is connected to one end of resistor R8. One end of capacitor C8 is connected to the connection point between R2 and R14, and the other end of capacitor C8 is grounded.

3. The oscilloscope automatic triggering circuit based on sound detection according to claim 2, characterized in that: The signal amplification circuit includes an operational amplifier U1B and a resistor R12. The other end of resistor R8 and one end of resistor R12 are both connected to the inverting input terminal of operational amplifier U1B. The non-inverting input terminal of operational amplifier U1B is connected to the junction of resistors R2 and R14. The other end of resistor R12 is connected to the output terminal of operational amplifier U1B.

4. The oscilloscope automatic triggering circuit based on sound detection according to claim 3, characterized in that: The bandpass filter circuit includes an operational amplifier U1A, resistors R5, R6, R10, R13, capacitors C3, C4, and C6. One end of resistor R6 is connected to the output of operational amplifier U1A, and the other end of resistor R6 is connected to one end of resistor R5, one end of capacitor C4, and one end of capacitor C6. The other end of resistor R5 is connected to the output of operational amplifier U1A. The other end of capacitor C4 is connected to the non-inverting input of operational amplifier U1A, and the other end of capacitor C6 is grounded. One end of resistor R10 is connected to the connection point of capacitor C4 and the non-inverting input of operational amplifier U1A, and the other end of resistor R10 is grounded. One end of capacitor C3 is connected to the positive power supply of operational amplifier U1A, and the other end of capacitor C3 is grounded. One end of resistor R13 is connected to the inverting input of operational amplifier U1A, and the other end of resistor R13 is connected to the output of operational amplifier U1A. The positive power supply of operational amplifier U1A is connected to the power supply Vcc, and the negative power supply of operational amplifier U1A is grounded.

5. The oscilloscope automatic triggering circuit based on sound detection according to claim 4, characterized in that: The signal triggering circuit includes operational amplifiers U2A and U2B, resistors R3, R4, R9, R11, R15, capacitors C1, C2, and C9. One end of resistor R9 is connected to the output terminal of operational amplifier U1A, and the other end is connected to the inverting input terminal of operational amplifier U2A. One end of resistor R3 is connected to the power supply Vcc, and the other end of resistor R3 is connected to one end of resistor R11. The other end of resistor R11 is connected to one end of resistor R15, and the other end of resistor R15 is grounded. One end of capacitor C2 is connected to the power supply Vcc, and the other end of capacitor C2 is connected to operational amplifier U2A. The non-inverting input of operational amplifier U2A is connected to the ground. One end of capacitor C1 is connected to the positive power supply terminal of operational amplifier U2A, and the other end of capacitor C1 is grounded. One end of capacitor C9 is connected to the inverting input terminal of operational amplifier U2B, and the other end of capacitor C9 is grounded. One end of resistor R4 is connected to the power supply Vcc, and the other end of resistor R4 is connected to the output terminal of operational amplifier U2A. The positive power supply terminal of operational amplifier U2A is connected to the power supply Vcc. The inverting input terminal of operational amplifier U2A is connected to the non-inverting input terminal of operational amplifier U2B. The negative power supply terminal of operational amplifier U2A is grounded. The output terminal of operational amplifier U2B is connected to the output terminal of operational amplifier U2A.

6. The oscilloscope automatic triggering circuit based on sound detection according to claim 5, characterized in that: The signal output circuit includes a resistor R7, a capacitor C7, a BNC connector P1, and a transient voltage suppression diode TVS1. One end of the resistor R7 is connected to the output terminal of the operational amplifier U2A, and the other end of the resistor R7 is connected to one end of the capacitor C7, one end of the BNC connector P1, and one end of the transient voltage suppression diode TVS1. The other ends of the capacitor C7, the BNC connector P1, and the transient voltage suppression diode TVS1 are all grounded.