Contactless IC card system
AssigneeSony Corporation
InventorShigeru Arisawa
Life of this patent
Estimating the term…
Abstract
In a contactless IC card system, a modulating circuit manufactured in an IC form is operable at a high power efficiency. The demodulating apparatus is configured to include: signal processing means for producing first and second input signals; first clamping circuit for clamping said first input signal; second clamping circuit for clamping said second input signal; first band limiting means for removing a component of said first input signal from an output signal of said first clamping circuit; second band limiting means for removing a component of said second input signal from an output signal of said second clamping circuit; and calculating means for adding, or averaging an output signal of said first band limiting means and an output signal of said second band limiting means.
Claims4
A demodulating circuit, comprising:
- signal processing means for producing first and second input signals, wherein a phase of the first input signal is approximately 180 degrees different from a phase of the second input signal;
- first clamping circuit for clamping said first input signal;
- second clamping circuit for clamping said second input signal;
- first band limiting means for removing a component of said first input signal from an output signal of said first clamping circuit;
- second band limiting means for removing a component of said second input signal from an output signal of said second clamping circuit;
- and
- calculating means for adding, or averaging an output signal of said first band limiting means and an output signal of said second band limiting means.
Dependencies are inferred from the claim text.