SINGLE RF OSCILLATOR FOR RFID READERS WITH FREQUENCY TRANSLATION AND FILTERING

摘要

A transmitter shifts a baseband data signal having a bandwidth of 2OM using a tone signal having a frequency 6M, which centers a sideband of the data signal at zero frequency. The transmitter then filters the shifted signal to filter out the non- centered sideband, and then adds the tone signal to form a composite signal. The transmitter upconverts the composite signal during a first operational mode using a RP signal having a frequency ?c equal to a center frequency of a channel. In a second operational mode, the transmitter upconverts a DC level using the same RF signal. The upconverted DC level can be used as a continuous wave carrier signal having a frequency ?c- The transmitter has a single RF oscillator to output both a SSB signal centered at frequency ?c during the first mode and a carrier signal of frequency ?c during the second mode.