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Pro
• Easy to construct physical oscillators and filters (from tuning forks to tuned circuits consisting of capacitors and inductors) • Corresponds, intuitively, to aspects of human perception such as color and pitch. (The cochlea is, in fact, a real time audio spectrum analyzer.) • Technology for separating and distinguishing signals by frequency is now well developed • Narrowband antennas are simpler to construct and better understood than wideband antennas (at least today) and “naturally” filter by frequency • Frequencies of signals are relatively easy to shift via mixing with sine waves (“heterodyning”) and then filtering • Confining signals to a limited space (e.g. indoors) is easier if absorption spectra ofmaterials can be exploited • It’s tough to change now, due to massive investment in the existing regime! |
Con
• “Heisenberg uncertainty principle” dictates that frequency cannot be exactly determined at any point in time; therefore, no filter can be perfect and no slice of spectrum is 100% usable (there’s always waste at the edges; hence the need for "guard bands") • Disconnect from reality: All real life signals are time limited. What's more, a signal that’s time limited cannot truly be frequency limited • Some frequencies have characteristics (e.g. “skip”) which can cause unexpected interference at a great distance • Systems designed for a specific frequency are not easily “re-tunable” to others, making reallocation difficult (not only on the fly, but even with long notice) and expensive • Varying absorption spectra of materials (air, water, buildings) cause some frequencies to be “beachfront property” while others are of limited use. A different basis set could equalize the practical value of different allocations, eliminating some of the artificial scarcities caused by allocation by frequency • Some alternative schemes could make “sharing” of the airwaves easier, due to increased agility, etc. |