RF transceivers are devices or modules that contain both a transmitter (Tx) and a receiver (Rx). Tx and Rx elements usually share functionality including antenna interface, low pass filtering, Rx/Tx switching and associated control circuits. RF isolation elements like circulators and diplexers may also be required in the shared RF path. They are used in applications that require wireless interfaces including NFC/RFID transponders, RF modems, WiFi, Bluetooth, RF mesh networks, access control, security systems, remote control, cellular and cordless phones.Transceivers are defined by the way the Rx and Tx communication channel access is managed. This can be half duplex or full duplex communications. Dedicated Rx or Tx devices are referred to as operating in a simplex mode. Full duplex (FDX) transceivers can transmit and receive simultaneously using a diplexer or duplexer. Diplexers allow Tx and Rx to operate on different frequencies whilst sharing antenna circuits. Diplexers are non-overlapping band pass filters with RF power splitter/combiners. A duplexer allows Tx and Rx to operate simultaneously by using a polarization device for Tx to Rx port isolation like waveguide filters and RF circulators. Half duplex (HDX) transceivers can either transmit or receive but not both simultaneously. Examples of this are analog PMR FM radio transceiver modules. HDX can emulate FDX by using an RF switch as a duplexer to rapidly switch between Rx and Tx in a manner defined by the physical layer protocol called time division multiplex (TDM). Examples of these include WiFi modules.Key characteristics of transceivers incorporate the independent specifications of the receiver and transmitter. Receiver specifications include RF frequency band and channels supported, the Rx Sensitivity associated with the receiver noise figure (NF) and the Rx selectivity associated with its ability to receive the signal correctly in the presence of adjacent channel interference. In a digital receiver specifications associated with inter-symbol-interference (ISI) and bit-error-rate (BER) are important. Transmitters have specifications like efficiency but usually defined in the context of the whole transceiver as a function of Rx, Tx and standby cycle percentages. They will have input and output power specifications and transmitters will be required to conform with an RF spectrum envelope.Transceivers are a fundamental element to wireless communications. They alleviate the need for expensive cabling infrastructure. This also provides for reduction in associated mining and manufacturing that has ecological advantages. Wireless allows mobility and portability, facilitates miniaturization and reduces the need for connectors. Read more Read less