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US 6,586,988 B2Granted
Demodulating circuits for contactless integrated circuit cards and systems
AssigneeSony Corporation
InventorShigeru Arisawa
Life of this patent
Estimating the term…
Abstract
A demodulating circuit for use in contactless integrated circuit cards and systems, the demodulating circuit receiving an input signal, biasing the input signal by a preselected voltage, amplifying the signal such that is becomes half-wave rectified, and removing a modulation signal component from the signal, thereby demodulating the signal in a simple and efficient manner.
Claims6
A demodulating circuit comprising:
- an input for receiving a modulated input signal;
- bias components for directly biasing said modulated input signal such that only a half-wave of said modulated input signal is amplified when said biased input signal is subsequently amplified;
- an amplifier for amplifying said biased input signal such that said modulated input signal is half-wave rectified;
- and
- a band limiter for removing a carrier component of said modulated input signal from an output signal derived from said amplifier to demodulate said modulated input signal.
2 more elements
A demodulating circuit comprising:
- an input for receiving a modulated input signal;
- an amplifier for directly amplifying said modulated input signal;
- a limiter for limiting an amplitude of said amplified input signal such that only a half-wave of said modulated input signal is amplified;
- and
- a band limiter for removing a carrier component of said modulated input signal from an output signal derived from said limiter to demodulate said modulated input signal.
2 more elements
A demodulating circuit comprising:
- a limiter for limiting an amplitude of an input signal, wherein said limiter is configured as a series circuit formed by connecting a diode in series with a constant voltage power source;
- and
- band limiting means for removing a component of said input signal from an output signal derived from said limiter.
Dependencies are inferred from the claim text.