Patent AT-E400857-T1: [Translated] METHOD AND DEVICE FOR SUPPRESSING A TRANSMISSION SIGNAL IN A RECEIVER OF AN RFID WRITING/READING DEVICE

A method and apparatus is disclosed for operating an RFID read/write unit with transmitting signal suppression. The RFID read/write unit comprises a radio frequency part including a transmitter and a receiver, and a baseband part based on digital signal processing. The method involves producing an amplitude and phase weighted copy of a transmitting signal, namely a compensation signal, with the baseband part. After linear modulation of the compensation signal, a resultant signal at an input of the receiver is subtracted in an addition stage from a spurious coupling signal. The transmitting signal has an auxiliary signal impressed upon a carrier signal from the RFID read/write unit with a frequency offset fd, for the purpose of processing without any DC voltage in the receiver downstream of an RX converter. The input of the receiver comprises a turn-on and turn-off attenuation element which protects the radio frequency part.