Synchronous-phase contactless demodulation method, and associated demodulator and reader
First Claim
Patent Images
1. A method of demodulating signals from an electromagnetic field induced by a contactless transponder in a system having a reader comprising a first antenna and a second antenna, the method comprising the steps of:
- detecting, by the first antenna in the reader, modulation of the electromagnetic field induced by the transponder;
sensing, by the second antenna, a phase of the electromagnetic field;
controlling the detection of the modulation in accordance with the sensed phase of the electromagnetic field.
5 Assignments
0 Petitions
Accused Products
Abstract
A method of demodulating signals of an electromagnetic field induced by a contactless transponder includes a step in which the signals from the transponder are detected at given times or frequency. The times or frequency of the detection are synchronized in phase with the electromagnetic field. An associated demodulator and reader are also disclosed.
11 Citations
12 Claims
-
1. A method of demodulating signals from an electromagnetic field induced by a contactless transponder in a system having a reader comprising a first antenna and a second antenna, the method comprising the steps of:
-
detecting, by the first antenna in the reader, modulation of the electromagnetic field induced by the transponder; sensing, by the second antenna, a phase of the electromagnetic field; controlling the detection of the modulation in accordance with the sensed phase of the electromagnetic field. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A contactless transponder reader comprising:
-
a main antenna for detecting modulation of an electromagnetic field; an electromagnetic signal demodulator comprising means of sampling the modulation of the electromagnetic field detected by the main antenna; and a synchronization means comprising a secondary antenna which is detuned with respect to the main antenna, wherein the synchronization means uses the secondary antenna to sense a phase of the electromagnetic field and controls the detection of the modulation in accordance with the sensed phase of the electromagnetic field. - View Dependent Claims (7, 8, 9, 10, 11)
-
-
12. A demodulator for signals induced by a contactless transponder in an electromagnetic field, said demodulator comprising:
-
a detector for detecting modulation of the electromagnetic field induced by the transponder that are received via a primary antenna of a reader, means of controlling the detection of the modulation in accordance with a phase of the electromagnetic field sensed by a secondary antenna of the reader, wherein the controlling means continuously provides synchronization of the detection of the modulation with the phase of the electromagnetic field sensed by the secondary antenna.
-
Specification