QUALITY ADJUSTMENT OF A RECEIVING CIRCUIT

• US 20100127820A1
• Filed: 01/16/2008
• Published: 05/27/2010
• Est. Priority Date: 01/31/2007
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Continental Automotive GmbH (Continental AG)
• Inventors: Froitzheim, Herbert
• Granted Patent: US 9,148,189 B2
• Time in Patent Office: Days
• US Class Current: 340/5.200
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H

Abstract

A receiving circuit for a communication unit of an access device has a resonance circuit (1) with a receiving coil (L) for converting a magnetic induction into electrical current, and a capacitor (C). The receiving circuit (10) further has a first resistor (R1) and a switching element (3) designed for controllably connecting and disconnecting the first resistor (R1) to the resonance circuit (1). The receiving circuit electrically connects the resonance circuit (1) to the first resistor (R1) when the circuitry of the resonance circuit (1) changes from a first circuitry (7) to a second circuitry (8), and electrically disconnects the first resistor (R1) from the resonance circuit (1) when the circuitry of the resonance circuit (1) changes from the second circuitry (8) to the first circuitry (7).

Claims

1. A receiving circuit for a communication device of an access arrangement having a resonant circuit comprising a receiving coil for converting magnetic induction into electrical current, and a capacitor

wherein the receiving circuit also has a first resistor and a switching element designed to controllably connect and disconnect the first resistor to the resonant circuit.

2. The receiving circuit according to claim 1,

wherein the receiving coil and the capacitor are arranged in a parallel connection.

3. The receiving circuit according to claim 1,

wherein

the receiving coil and the capacitor are arranged connected in series.

4. The receiving circuit according to claim 1,

wherein

the switching element has a first switched state for connecting the resonant circuit and first resistor in a parallel connection.

5. The receiving circuit according to claim 1,

wherein

the switching element has a first switched state for connecting the resonant circuit and first resistor in a series connection.

6. The receiving circuit according to claim 1,

wherein

the switching element has a second switched state for disconnecting an electrical connection between the resonant circuit and the first resistor.

7. The receiving circuit according to claim 1,

wherein

the resonant circuit comprises a further resistor which is connected in parallel or in series with the receiving coil and/or the capacitor.

8. A communication device for an access arrangement having a receiving circuit as claimed in claim 1.

9. An access arrangement comprising:

a first communication device for emitting at least one interrogation signal in the inductive frequency range;

a second communication device having a receiving circuit according to claim 1 for receiving and processing the interrogation signal in the inductive frequency range.

17. The access arrangement according to claim 9,

wherein the switching element has a first switched state for connecting the resonant circuit and first resistor in a parallel connection.

18. The access arrangement according to claim 9,

wherein the switching element has a first switched state for connecting the resonant circuit and first resistor in a series connection.

19. The access arrangement according to claim 9,

wherein the switching element has a second switched state for disconnecting an electrical connection between the resonant circuit and the first resistor.

20. The access arrangement according to claim 9,

wherein the resonant circuit comprises a further resistor which is connected in parallel or in series with the receiving coil and/or the capacitor.

10. A method for changing the quality of a resonant circuit comprising the steps of

electrically connecting the resonant circuit to a first resistor if the circuitry of the resonant circuit changes from first circuitry to second circuitry, and with

electrically disconnecting the first resistor from the resonant circuit if the circuitry of the resonant circuit changes from the second circuitry to the first circuitry.

11. The method according to claim 10,

wherein the electrical connection and the electrical disconnection of the resonant circuit and first resistor are performed at just one of the lines which are designed for the electrical connection of said resonant circuit and first resistor.

12. The method according to claim 10,

wherein connecting and disconnecting are performed using a switching element.

13. The method according to claim 12,

wherein the switching element has a first switched state for connecting the resonant circuit and first resistor in a parallel connection.

14. The method according to claim 12,

wherein the switching element has a first switched state for connecting the resonant circuit and first resistor in a series connection.

15. The method according to claim 12,

wherein the switching element has a second switched state for disconnecting an electrical connection between the resonant circuit and the first resistor.

16. The method according to claim 10,

wherein the resonant circuit comprises a further resistor which is connected in parallel or in series with the receiving coil and/or the capacitor.