jmpsmash
100+ Head-Fier
what a differential pair mean is that there are 2 conductors and the receiving device takes the difference between the 2 conductors as the signal. so a signal coming from the source device will be converted to a positive and negative version of itself and then passed to the positive and negative conductor respectively. mathematically: positive - negative = 2 positive
normally, since the cable is next to each other, the same noise is introduced into the 2 conductors, then the receiving device will cancel out the noise. mathematically: (positive+noise) - (negative+noise) = 2 positive
2 conductors sitting parallel to each other are not the same EXACT distance to the noise source though, esp if the noise source is close by, twisted pair fixes this. twisted differential pair, or just twisted pair, is better than 2 separate parallel cables because in a twisted pair, the average distance of the 2 cables to the source of the noise is the same therefore the strength of the noise is the same. mathematically, same as above, but just ensures the positive noise = negative noise as close as possible. the difference in distance is really small, but for things like microphone cable in concert hall or for long runs of ethernet cable the total difference can be significant.
Shield is another way to reduce noise, if the shield is properly grounded, it forms what's is called a Faraday cage and block the noise from getting to the signal cable.
normally, since the cable is next to each other, the same noise is introduced into the 2 conductors, then the receiving device will cancel out the noise. mathematically: (positive+noise) - (negative+noise) = 2 positive
2 conductors sitting parallel to each other are not the same EXACT distance to the noise source though, esp if the noise source is close by, twisted pair fixes this. twisted differential pair, or just twisted pair, is better than 2 separate parallel cables because in a twisted pair, the average distance of the 2 cables to the source of the noise is the same therefore the strength of the noise is the same. mathematically, same as above, but just ensures the positive noise = negative noise as close as possible. the difference in distance is really small, but for things like microphone cable in concert hall or for long runs of ethernet cable the total difference can be significant.
Shield is another way to reduce noise, if the shield is properly grounded, it forms what's is called a Faraday cage and block the noise from getting to the signal cable.
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