|MadSci Network: Computer Science|
I assume that by asking, what is digital, you mean what is the difference between a digital and an analogue design or signal. The easiest comparison that comes to mind, is one of a telephone line carrying data. Imagine that the data in the analogue case, is carried as high pitched sounds (modem "shrieks") which are translated at the modem into data. The "shrieks" are the way the data has to travel down a line designed for analogue operations. If you examine a waveform for an analog transmission, you will observe that it has lots of irregular peaks and valleys. The problem that this carries is this: When the analogue signal is carried over long distances it tends to degrade, and introduce errors to the signal. Because of the nature of the waveform, those errors cannot be easily identified and rectified. Now, the digital signal is quite different. Instead of irregular peaks and valleys in the waveform, you have a nice clear signal that looks something like this: _______ ______ ______ | | | | | | | | | | | | | | | | | | ________| |____| |__________| |_________ That looks much nicer doesnt it? Not only does it look nice, it is also much easier to detect and correct errors in the stream. The reason behind this is in the logic of the digital stream itself. Data is transmitted as differences in the voltage applied to the line, commonly +5 volts for a binary 1 and 0 volts for a binary 0. Whatever device is at the other end, makes sense of the digital data, in the way it was programmed to do. The digital signal is also much easier to "boost" for transmission over long distances, again because of the waveform type. I hope this is what you were looking for. Yiannis
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