Stmicroelectronics Razvoj Polprevodnikov D.o.o.

Ams R&d Analogni Polprevodniki, D.o.o.

Jernej Rozman

Vinko Kunc

Maja Atanasijevic-Kunc

Tilen Svete

A circuit includes an in-phase/quadrature down converter configured to be coupled to an antenna of a first NFC (near field communication) device. DC cancellation circuitry is coupled at outputs of the converter. Detection circuitry is configured to analyze DC signals output by the DC cancellation circuits to detect the presence of a second NFC device.

Low power mode card detection

A method is performed for a signal transmitted by an RFID interrogator being a radiofrequency electromagnetic sine wave. An amplitude noise contribution RSdto a demodulated received signal RSd within a frequency interval of a low-pass filter is determined by means of a measured demodulated transmitted signal TSd as RSd=k.TSd in that a dc component DCin said demodulated received signal RSd and a dc component DCin said demodulated transmitted signal TSd are measured and a conversion factor k is determined as k=DC:DC. A receiver output signal O is continuously generated out of the received signal by subtracting said amplitude noise contribution RSdfrom the demodulated received signal RSd, filtering the cleaned signal RSd-k.TSd by the low-pass filter and amplifying it. The conversion factor is determined in an exceptionally simplified way as said ratio of said dc components. No receiving interruptions are needed.

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Ravne na Koroskem, Slovenia

Jernej Rozman