Audio monitoring is also called the core component pickup how to install?

Nowadays, people have more and more sudden accidents in their daily lives, and people have more and more strong awareness of prevention. Video surveillance has become one of the important sources of evidence for people to collect. The more attention you pay. In the field of security video surveillance, the addition of audio surveillance makes monitoring no longer just a "silent movie." In recent years, some relevant national policies have been issued, requiring some surveillance sites to synchronize video and audio. This has also brought a certain market to audio surveillance, and the goal has begun to rise from “visible” to “see clearly” and “listen”. See you."

Nowadays, people have more and more sudden accidents in their daily lives, and people have more and more strong awareness of prevention. Video surveillance has become one of the important sources of evidence for people to collect. The more attention you pay. In the field of security video surveillance, the addition of audio surveillance makes monitoring no longer just a "silent movie." In recent years, some relevant national policies have been issued, requiring some surveillance sites to synchronize video and audio. This has also brought a certain market to audio surveillance, and the goal has begun to rise from “visible” to “see clearly” and “listen”. See you."

At present, audio monitoring has been widely used in public facilities. A complete audio monitoring system includes a sound collection part, a voice noise reduction processing part, a network recording part, a voice intercom part, and a sound intelligent analysis part. Through the scene analysis of audio monitoring to judge the abnormal behavior in the public scene, this technology is based on the characteristics of various abnormal sounds in the time domain and the frequency domain, and the classification method combined with the pattern recognition can alarm the abnormal events.

The pickup is the core of the audio monitoring system. For the integrated monitoring of audio and video - the camera is the "eye" and the pickup is the "ear". The image seen by the eye and the sound heard by the ear are transmitted to the hard disk recorder as a brain through a nervous system such as a cable, an optical fiber, or a network to constitute a basic video recording system. How to install the pickup?

Pickup installation

First, the choice of the installation position of the pickup

The pickup can be installed on the ceiling or wall, and the installation position is as close as possible to the main conversation area. For example, the interrogation room can be installed near the auditee; the classroom can be installed near the podium; and the small conference room can be installed in the center of the ceiling. Principle: Try to be as close as possible to the main conversation area, which makes the pickup better.

Second, the selection and wiring of the pickup cable

The installation of the pickup takes into account the complicated construction environment. It is recommended to use a 0.5mm2 cross-section 3-core signal cable, which is a commonly used 3×0.5RVVP cable. The power supply of the pickup is generally a remote centralized power supply mode (that is, centralized power supply at the audio recording device end/sound amplification device end), and the three-core cable used is a power line, an audio signal line, and a common ground line. Shielded cables can be used in electromagnetic complex environments, and the shield is connected to the equipment ground at one end. That is, the shielding net connected to one end of the pickup is suspended, and the shielding net connected to one end of the audio device is connected to the equipment ground (the casing). Note: It is best to use separate wiring when wiring, do not use the same cable slot with strong current such as AC, and try to stay away from strong electromagnetic interference equipment such as transformers and lamp rectifiers.

Third, the power supply mode of the pickup

The power supply mode of the pickup requires remote centralized power supply (that is, centralized power supply at the audio recording device end/sound amplification device end), and its main purpose is to be more resistant to interference and noise. Since the pickup is a very sensitive small-signal amplification device, it is sensitive to the clutter of the power supply, and it is necessary to use a clean high-quality DC stabilized power supply with small clutter. A single pickup consumes approximately 10-30 mA of current, which means that a nominally 1 amp DC regulated power supply can operate with at least 10 pickups simultaneously.

Power efficiency and line loss should be considered in the application. Try to use a power supply with a higher nominal value. The DC regulated power supply referred to here is a commonly called "transformer", which is generally composed of a power transformer, a rectifier diode, a filter capacitor, and an integrated voltage regulator. Switching power supplies cannot be used, which can introduce a large amount of circuit noise to the pickup.

Fourth, the common ground connection of the pickup power supply negative and audio ground

The audio ground of the pickup and the negative pole of the power supply are combined into one. It must be connected to the negative pole of the DC stabilized power supply and the ground of the audio input (LineIn) of the audio equipment. If the power ground and the audio ground are not well connected, the sound quality may be degraded or there may be no sound. If the ground of the LineIn terminal of the audio device is not connected to the ground of the pickup, the sound will generally be very small.

Fifth, the connection of the audio cable of the pickup

Pickup audio signal cable and audio ground can be directly connected to the device: with audio-visual headphones, active speakers, audio amplifiers, audio and video distributors, DVR hard disk recorders, video servers, mixers, recorders, sound cards or other audio equipment LineIn linear input (no connection to microphone interface).

1. DVR. DVRs all have corresponding audio input ports, generally coaxial cable BNC plugs. The pickup audio cable needs to be connected to the center pin position of the BNC plug, and the pickup publicly needs to be connected to the outer casing of the BNC plug (that is, the shielded copper mesh that connects the coaxial cable).

2, the active speaker with its own amplifier. A set of ordinary active speakers are generally left and right, corresponding to the left and right channels of the audio line. This pickup only provides one source, so it is a “mono” source. The audio cable of the pickup is connected to the left/right channel audio cable of the speaker cable, and the pickup is connected to the ground of the speaker cable in common.

3. Other connection methods of audio equipment such as power amplifiers and mixers are equivalent to the above methods.

4. It is strictly forbidden to connect the pickup to the microphone (MIC) input of the sound card, mixer, amplifier, etc., otherwise the device may be damaged. This is because although the inside of the pickup also contains a microphone, it also includes circuits such as amplification, noise reduction, and echo processing, and outputs a "LineOut" audio signal of 1 Vpp or more.

5, notebook computers are rarely equipped with "LineIn" audio input jacks, generally only equipped with MIC input jacks and SPEAKER output jacks. The pickup can't be directly connected to the MIC port. You can only purchase a professional external USB interface desktop sound card and use the “LineIn” port to connect it.

6. The audio cable of the pickup cannot be directly connected to the two audio devices. The pickup adapter must be connected to avoid the deterioration of the sound quality caused by the impedance mismatch.

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