Patent ID: 8543163

Claim:
A signal enhancer chip for a radio frequency identification system, comprising: a receiving circuit comprising a demodulation amplification module for amplifying and demodulating communication signals received from a dual interface SIM card, and then outputting an analog communication signal, and a digital quantizing module for converting the analog communication signal to a digital communication signal; a sending circuit comprising a logic control module for processing the digital communication signal received from the digital quantizing module and generating a subsidiary carrier wave signal necessary for returning to a reader, and a modulation module for generating a communication signal to be sent according to the subsidiary carrier wave signal; a power supply module; and a filter for filtering the communication signals received from the dual interface SIM card, and then outputting the communication signals to the demodulation amplification module; wherein the filter comprises: a band-pass filter for filtering modulation wave signals and carrier wave signals received from the dual interface SIM card; and a band-stop filter for filtering modulation wave signals and carrier wave signals sent from the reader; wherein the central frequency of the band-pass filter and the band-stop filter is the same with the frequency of the carrier wave signals sent from a signal enhancer or from the reader.