elektoracle

Until recently, telecommunications have been restricted almost exclusively to electromagnetic radiation - and the low frequency end of the band at that. But things are changing. The main transmission media have always been cables and more-or-less shortwave electromagnetic carrier. The type of modulation and the wavelength vary according to the application; amplitude, frequency, phase and pulse- code modulation are well-known, as are long, medium and short waves. Funnily enough, when the waves get very short we suddenly start talking about frequency: Very High Frequency, Ultra High Frequency and Gigahertz range. The gigahertz range (i.e. wavelength in millimetres) is already in regular use for space communications, and the first applications in the domestic field have been announced recently.