A transceiver for a RFID reader and a transceiver for a RFID transponder
(tag) allow communication between the two devices. The RFID reader
utilizes an analog front end and a digital backend. In the receiver
portion of the transceiver, the front end of the RFID reader uses a pair
of down-conversion mixers to demodulate a received signal into in-phase
(I) and quadrature (Q) components and analog-to-digital converters (ADC)
digitize the signal. A digital signal processor (DSP) in the back end
processes the digital signal and uses a matched filter for data
detection. The RFID tag receives an inductively coupled signal from the
reader and the receiver portion of the tag uses a pulse/level detector
that employs an analog comparator and a sample and hold circuit to detect
the received signal. A digital decoder/controller is used to decode the
incoming data and to establish a sampling clock for the pulse/level
detector. An automatic gain control (AGC) circuit adjusts a receiver gain
according to the received signal strength and controls tuning of magnetic
coupling circuitry.