DATA TRANSMISION WITHOUT NOISE

Ever wondered how we can transmit serial data as fast as it does a SATA 3 ? The explanation is simple. Using a differential transmission line. This type of circuit requires three wires (minimum) to transmit information . Source goes one common and the other two with +V(t) and -V(t). That is, one is inverted relative to the other . Now we can imagine a very long cable line suffering interference on its way . Since "interference affects the two signals in the same way", if a noise signal N(t) goes into the line, we get +V(t)+N(t) in a cable and -V(t)+N(t) on the other. At the destination, the electronic circuit inverts the signal -V(t)+N(t) giving +V(t)-N(t). Then add both getting signals (+V(t)+N(t))+(+V(t)-N(t)) = 2V(t). As we can see not only a signal without noise but also has twice the amplitude. In real life this is not so . My circuit emulates this. Sinusoidal waveform generators are 180 degrees out of phase to simulate the two +V(t) and -V(t) signals. The square wave generator is modified to simulate the noise N(t). The two left operational are to introducing noise on the line while the two on the right are responsible for investing a signal and add it to the other to finally give the output . The colors are: RED for NOISE N(t), BLUE for +V(t)+N(t), ORANGE for -V(t)+N(t) and GREEN for the 2V(t) OUTPUT.

published 12 years ago