Radio frequency engineering is the analysis and design of circuits at frequencies where transmission lines are comparable to the wavelength. It includes the study of amplifiers, oscillators, mixers, demodulators (including PLLs) and antennas. This is relevant to RFID, broadcasting, radar, wireless computer networks etc. Typical frequencies of commercial radio frequency systems are from 10 megahertz (10e6 Hz) to 16 gigahertz (16e9 Hz).