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Matthew
Posts:
42
Registered:
4/6/12


Interpreting normalized data as a bitstream
Posted:
May 2, 2013 5:31 PM


When a binary bitstream (sequence of 0s and 1s) is passed through a channel, it is often distorted. Upon receiving the transmitted bitstream, how could one reinterpret it as a binary vector? I suppose this is also known as demodulation or bitstream synthesis, and I am aware of other sources of errors, such as jitter, but to keep things simple, I am not accounting for them. For example, after transmission, the vector 15bit vector v = [0 1 1 1 0 0 1 0 1 1 0 1 0 0 0] might be received as a vector of 15,000 data points (depending upon the sampling rate) that lie between y=0 and y=1 (or between 1 and 1). The original pattern of binary bits would be discernible from plotting the received (distorted) vector: one can visually detect a peak of what must be three 1s, followed by a valley of what must be two 0s, etc. Note that one simply could not use the "round" function, since peaks or valleys may no longer be found close to 1 or 0, respectively (for instance, what should be a '1', would be distorted to be y=0.3 or y=0.7). I have looked into using the first and second derivatives (regions of increasing and decreasing and concavity), but this is not foolproof (it seems like such a simple problem!) Any suggestions? Thanks!



