Radio frequency (RF)
receivers are used in a wide variety of applications such as wireless local area networks (LANs),
television,
cellular phones,
pagers,
global positioning system (GPS) receivers,
cable modems,
personal digital assistants (PDAs),
cordless phones, and other
radio frequency (RF) devices. RF receivers all require frequency translation or mixing. Radio frequency (RF) mixers, also knows as modulators, are used to up convert an IF input signal having an intermediate frequency to a desired output signal having an radio frequency (IF). A receiver circuit typically receives a radio frequency (RF) modulated signal from an antenna. The receiver includes an input low-noise amplifier followed by a filter and a mixer. RF mixers are used to shift signals from lower to higher frequencies or from higher to lower frequencies. A mixer multiplies its signal inputs often producing very complex products in the process. RF mixers include a transconductor and a commutating stage switching section driven by signals from a local oscillator.
