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#GROUND LOOP ISOLATOR TV#

Is transmitted through twisted pair wiring (some CCTV applications Have had differential inputs and option to disconnect input ground connection).ĭifferential inputs are also used in applications where a video signal In some professiona video equipments (some video projectors I have seen Differential input with floating ground works nicelyįor small ground potential differences and this approach is used Those both technologies are usable in real Isolating video signal needs typically active technology which involvesĮlectro-optical isolation or differential amplifier with a floating ground (normal composite video can have bandwidth from 50 Hz to 6 Mhz). Is important and video signals have very high frequency spectrum Or antenna signals, because the DC level of the video signal Isolating video signal is more complicated than isolating audio

Cross-Talk: Ground loops can cause one signal to interfere with another, because every cable should ideally return through the corresponding shield conductor, but there's an alternative path through the other shield conductor which causes undesirable voltage differences to nearby cables.

These antennas are especially adept at picking up AM broadcasts if most of the loop is vertical. Any large loop of wire makes a good AM antenna.

RF Interference: Herring bone interference on video line is caused by a ground loop (that includes your coax shield) acting as an AM radio antenna.

If you have light dimmers nearby those humming bars can easily become quite severe and easily visible.

Hum Bars: The mains frequency (50 Hz or 60 Hz) can cause stationaly or moving horizonal humming bar to appear on the video signal (as shown on the picture above).

Ground loops in the video systems can have following effects:

#GROUND LOOP ISOLATOR TV#

TV signal because of ground loops in the system. The picture below is a real world example of the effects of a ground loopĪnd what it causes a a video picture received from the cable TV network:Īd you can see that video signal has strong hummign bars and Typically they are not as visible because bars are moving so fast that you see The same kind of bars can be also seen in computer screen, but Typically the humming can be seen as slowly vertically moving horizonal bars in

Video hum may be a problem in any system where video sources and displayĭevices are connected to different A/C power sources with varying grounding potentials. The video image, video hum may also cause video distortion or even tearing of the picture in Video hum is usually observed as bars rolling vertically through The ground lines which has influenced the video signal,Ĭausing degradation of the displayed signal. Video hum is low frequency (50 or 60 Hz mains frequency or it's harmonics) noise from As the source and destination of a video signal can be at differing ac or dc earth potentials, earth loop currents flow and cause longitudinal hum to be introduced into the video signal.