2006-08-08 06:21:30 · 2 answers · asked by porido2005 1 in Science & Mathematics ➔ Engineering
Some common schemes are polar, bipolar and manchester. With the presence of white gaussian noise in the transmission channel, the error probability is reduced when these schemes are used as compared to unipolar signals (0 and 1).
If you are using frequency or phase modulation then your carrier signal is going to be a sinusoid, and that will have positive and negative voltage as well
2006-08-09 15:09:03 · answer #1 · answered by Anonymous · 0⤊ 0⤋
It's easier to differentiate between +1 and -1 than 0 and 1.
It all depends on the type of system, but for example one could map a 1 to -1 and a 0 to +1.
Then when you receive a signal just look to see if it's positive or negative.
There are more probabilistic reasons too, due to noise, but that's the jist of it.
2006-08-08 14:32:28 · answer #2 · answered by cw 3 · 0⤊ 0⤋