Information Impedance Matching*

In electrical (power) and electronics (signal) engineering, there is a principle called “impedance matching”: to achieve the most effective transfer of energy from one part of a circuit to another part, match the parts, with certain characteristics, in a complementary way. The impedances should be complex conjugates at the operating frequency (resistances should be equal and the capacitive reactance of one should equal the inductive reactance of the other). For example, to produce as much light as possible with a certain battery and an incandescent bulb use a bulb not of extremely high resistance nor of extremely low resistance, but of resistance equal to the battery’s (internal) resistance. Match the filament impedance to the battery impedance. Similarly, in the communication of information the best representation of the information occurs when the data are displayed at the resolution indicated by the source: one pixel to one pixel. Thus, in loose analogy to the principle of electrical impedance matching, the principle of information impedance matching suggests itself, to describe the optimal matching of an information source and an information receiver. This analogy seems appropriate because the fields of information theory and signal processing implicitly recognize the equivalence o