Notes

(Dis)advantages of Digital (spike) vs. Non-Digital Communication There are several disadvantages to sending digital signals along a channel. One of them is quantization loss (as shown in the figure). As we can clearly see, the output waveform (blue) is not perfectly in line with the original analogue input waveform (red). The calculation to determine quanta is straightforward. As an aside, non-linear quantization techniques and schemas exist. One can take advantage of alternative quantization techniques to digitize an analogue signal that has a different entropy, or more information concentrated at lower values at the cost of reducing the resolution in higher values. The most striking argument for analogue activity is given by Shannon's Information Capacity. A calculation done for Crab neurons demonstrates that an analogue channel transfers 2500-6000 bits/s while a digital channel would have 50-220 bits/s: an order of magnitude inferior to an analogue channel. On the other side, the advantage of digital information is that we experience no signal loss during signal transmission across long distances.