【 Weak current College 】 audio device noise prevention and elimination---Power By 【 China power house network 】

We usually use audio devices and systems, more or less will encounter noise problem, and often the noise comparison is not easy to solve the problem is that does not accurately identify the root of the problem. In some large audio system, often to multiple mixer-centric subsystems, or to and video equipment systems interconnection. Sometimes the distal end of the sound and video system to transmit signals, radio stations and even useful telephone line transmission audio broadcasting live broadcast signals. These remote connections, because different subsystem has its own separate earthing system, 2 system once the ground wire to the inevitable formation ground noise. On the other hand, because of the long distance transmission, transmission shield of grounding resistance increases, even with a non-shielded cable, is easy to introduce a large number of external electromagnetic radiation interference noise dangshan agriculture resort zone has. Prevention practice, all equipment is suspended, no dedicated ground conditions most commonly used a measure, this is an extremely unstable working conditions, often results in instability of random noise. To make the cable with shielding layer to shield them from outside of stray electromagnetic interference, must make the shield has the correct connection and good grounding. Therefore the entire system to a good grounding. To have a ground wire, grounding resistance of less than 4 Ω, you cannot use the power of zero line as audio system equipment of the ground. In the outdoor areas can be considered a temporary ground planted, the simplest way is to use 1 root 1m long steel or aluminum alloy tube inserted into the ground, the effect is pretty good. System to avoid chain grounding, but should use star grounding. It simply uses the chain grounding, when a device on the electromagnetic or static induction noise, as a result of the transmission line of shield and iron device shell grounding system of the entire system to produce induction voltage, which causes the system to produce a certain amount of noise level. This type of interference in link longer audio is particularly evident on the system. But on the contrary, Star grounding, each device by special ground received unified Earth point. This requires that all devices connected to the audio cable of the shield to ground on one side (add shield) and the device's ground lead through specialized wire connected to an Earth point (usually near the mixer). If the signal transmission lines at both ends of the Earth, the shield are necessarily form the ground loop, when the loop of the other equipment, electromagnetic interference shielding the cable will appear near that have serious interference noise, and circuit noise interference. To ensure that the system does not appear in the loop structure, required equipment can only be between a grounding wire cross edge. The requirements are not stringent, lets not balance device suspension, through audio signal cable public next level equipment of the ground, using chain earthing. This chain-shaped grounded series can not be too much, generally not more than 2 levels, otherwise it will cause a serious increase of noise. The enclosure is attached to the issue between also attracts attention, for example, many devices installed in the same rack. If each device individually answered the ground, 2 sets of equipment for installation in the same rack and makes the enclosure is connected to a ground loop. Troubleshoot using optical isolation means completely isolate different subsystems, the best results. For example: MD recorder with 2 sets of 1-core optical fiber connection to one of analog input connection to an audio subsystem, another of fiber input received before one of the fiber output signal, and then to its analog output port output signal sent to the remote end of the audio subsystem, 2 VCL is set to record sound preparatory work mode (REC READY) to work. Through this method, you can better noise for the prevention and elimination, recommended for everyone to reference.