Following on from a previous article on DSL and its scientific bases, I now want to review the fundamentals of another technology: radio. As with a DSL, the ability to transmit data in any radio communications system – from the very first Marconi experiments to 5G networks – is bound by Shannon’s equation, based on the channel’s bandwidth and signal-to-noise ratio. In radio, we also have another interesting equation that can tell us the received signal strength when the transmitter power and frequency, antenna characteristics and distance to the receiver are known.
The growing number of electronic devices and wireless technologies providing ever-increasing performances and speeds requires a set of common standards to ensure EMC electromagnetic compatibility.
Ever since Michael Faraday’s discovery in 1831 of the phenomenon of magnetic induction, which James Maxwell later integrated in his well-known set of equations, we know that any change in an electric current produces a magnetic effect in its vicinity.