Fault self-checking device for security sound pick-up

Abstract

The utility model discloses a fault self-checking device for a security sound pickup, which is characterized in that an MCU (Microprogrammed Control Unit) controls an ultrasonic transmitter to emit an ultrasonic self-checking signal, and a silicon microphone simultaneously picks up field sound and ultrasonic waves. The silicon microphone converts field sound and ultrasonic waves into electroacoustic signals, the electroacoustic signals are amplified by the preamplifier, and the amplified signals are output in two paths: one path passes through the 20kHz low-pass filter to output sound signals in an auditory frequency range; and one path passes through a 40kHz high-pass filter and is output to an MCU (Microprogrammed Control Unit) connected with the 40kHz high-pass filter. And the MCU compares the received ultrasonic signal with the ultrasonic signal transmitted by the ultrasonic transmitter, and judges whether the sound pickup function fails or not. According to the utility model, the fault self-detection is not interfered by field environment sound, the field voice is not interfered, the sound pickup is not influenced to output audio signals, the versatility is strong, and the cost is low.

Description

Technical Field

[0001] The utility model belongs to the technical field of fault self-detection, and in particular relates to a fault self-detection device for a security microphone. Background Art

[0002] A security microphone is a sound collection device used at the front end of a security system. Existing microphone fault self-test devices can consist of a microphone and a speaker, positioned within 10 cm of each other. The speaker plays a preset self-test audio signal at a volume close to speech pressure, approximately 50 dB. When the microphone is operating normally, it picks up live sound output. During a self-test, the control unit drives the speaker to emit a self-test audio signal. The microphone compares the picked-up self-test audio signal with the control unit's preset signal signature to determine if the microphone function is faulty.

[0003] In the security system, the microphone outputs the sound signal of the monitoring scene in real time. In particular, during the interrogation process of judicial organs, the recording is required to be carried out uninterruptedly to maintain its integrity.

[0004] When the monitoring scene is silent, the self-test audio sound emitted by the speaker will distract the attention of on-site personnel; at the same time, the self-test audio signal of the microphone is sent to the recording and monitoring system, and the recording system cannot restore the real sound of the scene; staff may experience auditory fatigue if they repeatedly hear the self-test audio signal.

[0005] When the microphone is performing self-test, the self-test audio sound emitted by the speaker is superimposed on the on-site voice. The self-test audio sound acts as non-specific background noise, which will confuse the on-site voice signal and interfere with the on-site voice sound. It will distract the on-site personnel and may cause them to misrecognize the voice or be unable to understand the voice content.

[0006] On-site personnel are installed at a certain distance from the microphone, and the microphone and speaker of the microphone are very close together. When the microphone is performing self-testing, the self-test audio sound pressure level received by the microphone is approximately 50dB, and the on-site voice sound pressure level received by the microphone is between 40-70dB. The two sounds are similar in loudness at the microphone end. After the sounds are spatially mixed and superimposed, the output signal is sent to the background monitoring and recording system. The volume of the two signals is close. The self-test audio signal is not on-site voice, which will interfere with the hearing of staff and make it impossible to hear some key words and other voice content. At the same time, it affects the authenticity of the recorded evidence and the clarity of the played back voice. It is necessary to ensure that the microphone is working properly during the judicial inquiry process, and to prevent the self-test audio sound from interfering with the on-site voice. Therefore, the self-test audio signal cannot be used to self-test the microphone fault. The self-test time of the microphone is limited and has certain limitations. Utility Model Content

[0007] In response to the above problems, the present invention provides a security microphone fault self-test device, which uses ultrasonic waves as self-test signals to continuously self-test the microphone function. The MCU control unit detects whether the frequencies of the ultrasonic signals sent and received are consistent to determine the microphone function.

[0008] A security pickup fault self-test device comprises a silicon microphone, a preamplifier, a 20kHz low-pass filter, a 40kHz high-pass filter, an MCU control unit, an ultrasonic transmitter, an indicator light, an alarm switch and a power supply circuit.

[0009] The MCU control unit is connected to the ultrasonic transmitter, controlling it to emit an ultrasonic self-test signal with a sound pressure of 50dB. A silicon microphone simultaneously picks up both the on-site sound and the ultrasonic waves. The silicon microphone converts these signals into electroacoustic signals, which are then amplified by a preamplifier. The amplified signals are then divided into two output paths: one that passes through a 20kHz low-pass filter and outputs a sound signal within the audible frequency range; and the other that passes through a 40kHz high-pass filter and is output to the MCU control unit connected to the 40kHz high-pass filter.

[0010] The MCU control unit compares the received ultrasonic signal with the ultrasonic signal emitted by the ultrasonic transmitter to determine whether the pickup function fails.

[0011] The power supply circuit is connected to the MCU control unit, and the MCU control unit supplies power to the silicon microphone, preamplifier, 20kHz low-pass filter, 40kHz high-pass filter, MCU control unit, ultrasonic transmitter, indicator light, and alarm switch.

[0012] The specific method of determining whether the microphone function is faulty is as follows: if the MCU control unit detects that the frequency of the received ultrasonic signal is consistent with that of the ultrasonic signal emitted by the ultrasonic transmitter, the microphone function is normal and the microphone outputs a live voice signal; otherwise, the microphone function is faulty, the MCU control unit triggers the alarm switch and outputs a signal, so that the MCU control unit controls the microphone live fault indicator to light up.

[0013] Beneficial effects of the utility model: The utility model adopts non-audio ultrasonic self-test signals, which are not affected by the ambient sound on site, will not interfere with the on-site voice, and will not affect the output audio signal of the pickup. The solution is simple, versatile and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the principle of the device of the utility model;

[0015] Figure 2 This is the effect diagram of the silicon microphone: it picks up the live sound and the ultrasonic waves emitted by the ultrasonic controller at the same time;

[0016] Figure 3 This is a detailed flow chart of the device of this utility model. DETAILED DESCRIPTION

[0017] This utility model proposes an innovative design of a security microphone fault self-test device, aiming to build an efficient and reliable microphone self-test system, ensuring that it can automatically monitor and respond to any performance anomalies in a 24-hour uninterrupted working cycle. When the microphone is damaged or stops working, it will immediately output an alarm signal, causing the alarm indicator to light up. At the same time, the self-test process will achieve zero interference with the output audio quality and the surrounding environment. Figure 1 As shown, the underlying principle of the device of the utility model is explained, and the MCU control unit controls the ultrasonic transmitter to send a self-test signal to perform self-test on the pickup.

[0018] In order to achieve accurate and efficient ultrasonic signal acquisition, a silicon microphone with high sensitivity and wide dynamic range was selected. At the same time, a preamplifier was used to significantly amplify the weak electroacoustic signal, which facilitates efficient comparison and identification of the subsequent MCU module.

[0019] If an ordinary microphone is used, the microphone may not be able to receive ultrasonic waves, or may only receive a part of the weak ultrasonic signal, resulting in incomplete or distorted signal reception and errors, which will reduce the accuracy of subsequent frequency judgment.

[0020] At the same time, the application of the preamplifier also significantly improves the problem of weak signals when not in use, ensuring that the MCU control unit can accurately identify and process ultrasonic signals, greatly reducing the possibility of false alarms.

[0021] During signal processing, a 20kHz low-pass filter and a 40kHz high-pass filter are used to precisely segment the sound signal. The former extracts and purifies the human voice and ambient sound, ensuring clear and low-distortion audio output; the latter reduces noise interference in the ultrasonic signal, enhancing the purity of the self-test signal. This dual filtering mechanism not only ensures audio output quality but also provides a more accurate signal foundation for the MCU control unit, enabling efficient frequency comparison and fault diagnosis.

[0022] The MCU controls the ultrasonic transmitter and alarm switch, comparing the ultrasonic signal it receives with the signal from the transmitter. If a frequency discrepancy or loss is detected, the alarm is triggered and the fault indicator light illuminates. This instant feedback mechanism significantly shortens fault discovery time and improves maintenance efficiency.

[0023] In order to build this complete self-test system, an ultrasonic transmitter, an indicator light, an alarm switch and a power supply circuit are added to jointly ensure the efficient operation and reliable performance of the device of the utility model.

[0024] The following is the working principle of the utility model device:

[0025] While the pickup is operating, the self-test function is also enabled. The power circuit is powered, and the MCU controls the ultrasonic transmitter to continuously emit ultrasonic signals. The ultrasonic signal frequency is above 20kHz, with a sound pressure of 50dB, achieving zero interference with the on-site environment and preventing auditory fatigue.

[0026] The silicon microphone then simultaneously picks up the on-site sound and the ultrasonic waves emitted by the ultrasonic transmitter, achieving good fidelity with high sensitivity, which is conducive to subsequent comparative judgment. Figure 2 This shows that ultrasonic waves are emitted by the ultrasonic transmitter as a self-test signal and enter the silicon microphone together with the on-site sound to achieve subsequent amplification, comparison and judgment.

[0027] The silicon microphone converts live sound and ultrasound into electroacoustic signals, and amplifies the signals under the action of the preamplifier, significantly improving the accuracy of the self-test system. The signals are then output in two ways: one through a 20kHz low-pass filter to output live audio; the other through a 40kHz high-pass filter to output ultrasonic self-test signals, which are collected by the MCU control unit.

[0028] The MCU control unit compares the ultrasonic signal it receives with the ultrasonic signal emitted by the ultrasonic transmitter, and determines whether the microphone function is faulty by comparing the frequencies: if the MCU control unit detects an ultrasonic signal with the same transmitting and receiving frequency, it determines that the microphone function is normal, and the alarm light will not light up; if the MCU control unit does not receive an ultrasonic signal, or does not detect an ultrasonic signal with the same transmitting and receiving frequency, it determines that the microphone function is faulty, and at the same time the MCU control unit triggers the alarm switch signal output, and the on-site fault indicator light lights up.

[0029] Figure 3 This is a detailed flow chart of the device of this utility model. The ultrasonic transmitter emits a continuous self-test ultrasonic signal, which is then picked up simultaneously by a silicon microphone. After electroacoustic signal conversion and preamplification by a preamplifier, the signals of different frequencies are separated by high-pass and low-pass filters. After passing through the high-pass filter, the ultrasonic self-test signal is input into the MCU control unit. If the input ultrasonic signal frequency is incorrect or the signal is lost, the microphone is judged to be malfunctioning and the indicator light illuminates. If the function is normal, the indicator light does not illuminate, and the system outputs the live sound signal after passing through the low-pass filter.

Claims

1. A security microphone fault self-detection device, characterized in that: Includes silicon microphone, preamplifier, 20kHz low-pass filter, 40kHz high-pass filter, MCU control unit, ultrasonic transmitter, indicator light, alarm switch and power supply circuit; The MCU control unit is connected to the ultrasonic transmitter to control the ultrasonic transmitter to send out an ultrasonic self-test signal with a sound pressure of 50dB. The silicon microphone picks up both the on-site sound and the ultrasonic wave. The silicon microphone converts live sound and ultrasonic waves into electroacoustic signals, which are amplified by the preamplifier. The amplified signals are then divided into two output channels: one channel passes through a 20kHz low-pass filter and outputs sound signals within the auditory frequency range; the other channel passes through a 40kHz high-pass filter and is output to the MCU control unit connected to the 40kHz high-pass filter. The MCU control unit compares the received ultrasonic signal with the ultrasonic signal emitted by the ultrasonic transmitter to determine whether the pickup function fails.

2. The security microphone fault self-test device according to claim 1, characterized in that: The power supply circuit is connected to the MCU control unit, and the MCU control unit supplies power to the silicon microphone, preamplifier, 20kHz low-pass filter, 40kHz high-pass filter, MCU control unit, ultrasonic transmitter, indicator light, and alarm switch.

3. The security microphone fault self-detection device according to claim 2, characterized in that: The specific method of determining whether the microphone function is faulty is as follows: if the MCU control unit detects that the frequency of the received ultrasonic signal is consistent with that of the ultrasonic signal emitted by the ultrasonic transmitter, the microphone function is normal and the microphone outputs a live voice signal; otherwise, the microphone function is faulty, the MCU control unit triggers the alarm switch and outputs a signal, so that the MCU control unit controls the microphone live fault indicator to light up.

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