Self adjusting antenna impedance for credential detection in an access control system
First Claim
1. A method of detecting the presence of a credential with a credential reader, the credential reader including an antenna circuit having an antenna to transmit and to receive a signal, the method comprising:
- transmitting an energizing signal with the antenna;
receiving a modified energizing signal with the antenna;
demodulating the received modified energizing signal to determine an I value and a Q value of the received modified energizing signal; and
adjusting a component of the antenna circuit as a function of one of the I value and the Q value.
1 Assignment
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Accused Products
Abstract
An access control device including a credential reader circuit structured to enter a standby mode, awaken from the standby mode, and receive data from a nearby credential, and a credential detection circuit. The credential detection circuit includes a memory configured to store program instructions, an antenna circuit, and a processor electrically coupled to the antenna circuit and to the credential reader circuit, wherein the processor configured to execute the stored program instructions to: transmit an energizing signal; receive a modulated energizing signal with the antenna circuit; transmit an activation signal to the credential reader circuit in response to the received modulated energizing signal, wherein the received modulated energizing signal includes I and Q values; receive a false detection signal from the credential reader circuit; and adjust an impedance of the antenna circuit.
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Citations
19 Claims
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1. A method of detecting the presence of a credential with a credential reader, the credential reader including an antenna circuit having an antenna to transmit and to receive a signal, the method comprising:
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transmitting an energizing signal with the antenna; receiving a modified energizing signal with the antenna; demodulating the received modified energizing signal to determine an I value and a Q value of the received modified energizing signal; and adjusting a component of the antenna circuit as a function of one of the I value and the Q value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An access control device comprising:
a credential reader and detection circuit structured to enter a standby mode, awaken from the standby mode, and receive data from a credential, the credential reader and detection circuit including; a memory configured to store program instructions; an antenna circuit, and a processor electrically coupled to the antenna circuit and to the credential reader and detection circuit, the processor configured to execute the stored program instructions to; transmit an energizing signal; receive a modulated energizing signal; transmit an interrupt signal in response to the received modulated energizing signal, wherein the received modulated energizing signal has I and Q values; receive a false detection signal; and adjust an impedance of the antenna circuit in response to the received false detection signal. - View Dependent Claims (14, 15, 16, 17, 18, 19)
Specification