Receiver filter for dc-wander removal in a contactless smartcard

A system for processing a baseband signal in a Direct Current (DC)-suppressed system, the system comprising:

• a first high pass filter (HPF) configured to process the baseband signal in the analog domain;
• an analog-to-digital converter (ADC) configured to convert the processed baseband signal to a digital signal;
• and
• a second HPF configured to process the digital signal in the digital domain to provide a discrete-time differentiation of the baseband signal.

A smart card comprising:

• an antenna configured to receive a wireless signal;
• an analog front-end configured to process the wireless signal and to convert the wireless signal into a digital signal;
• a digital signal processing (DSP) unit configured to perform digital signal processing on the digital signal;
• and
• a processor configured to process the digital signal from the DSP unit according to one or more protocols,
• wherein the analog front-end comprises:
• a demodulator configured to demodulate the wireless signal into a baseband signal;
• a first high pass filter (HPF) configured to process the baseband signal in the analog domain;
• and
• an analog-to-digital converter (ADC) configured to convert the processed baseband signal to the digital signal,
• and wherein the DSP unit comprises a second HPF configured to process the digital signal in the digital domain to provide a discrete-time differentiation of the baseband signal.