Static antenna tuning and antenna voltage measurement

• US 5,856,809 A
• Filed: 01/22/1997
• Issued: 01/05/1999
• Est. Priority Date: 01/22/1997
• Status: Expired due to Fees

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Schoepfer, Harald
• Primary Examiner(s): Le, Hoanganh T.
• Application Number:
  US08/787,197
• Time in Patent Office: 713 Days
• Field of Search: 343/703, 343/860, 343/861, 343/850, 455/193.1, 455/193.2, 455/121, 455/123
• US Class Current: 343/703
• CPC Class Codes: G01R 29/10 Radiation diagrams of antennas
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors

Abstract

A static antenna tuning and antenna voltage measurement circuit (40) includes antenna voltage conversion circuitry (44) for converting a voltage signal (42) to a measurement signal representative of transmitter/receiver antenna (16) operation. Voltage signal (42) arises from transmitter/receiver antenna (16) transmitting or receiving a recognition signal (S1, S2). Comparator circuitry (48, 50, 52) compares the measurement signal to a predetermined optimal transmitter/receiver antenna operation signal. Control circuitry (54, 56) controls the tuning of transmitter/receiver antenna (16) such that (a) in the event that the measurement signal indicates optimal performance of transmitter/receiver antenna (16) relative to the predetermined optimal transmitter/receiver antenna operation signal, storing the measurement signal as the predetermined optimal transmitter/receiver antenna operation signal; (b) in the event that the measurement signal indicates less than optimal performance of transmitter/receiver antenna (16), generating a tuning signal to antenna tuning circuitry (56) associated with transmitter/receiver antenna (16); and (c) repeating steps (a) and (b) until an optimal transmitter/receiver antenna performance condition exists.

Claims

1. An improved antenna tuning apparatus for a transmitter/receiver antenna of a recognition system, said recognition system having an associated matching member which operates with a transponder to control a control mechanism of a device;

the matching member and other non-matching members containing facilities each of which, when receiving energy transmitted from said transmitter/receiver antenna produces a respective unique recognition signal in said transponder;

control of the device being possible only upon simultaneous occurrence of both operation of the control mechanism and production of a recognition signal by the matching member;

wherein the improved static antenna tuning and antenna voltage measurement apparatus comprises;

antenna voltage conversion circuitry for converting a voltage signal to a measurement signal representative of transmitter/receiver antenna operation, said voltage signal arising from said transmitter/receiver antenna transmitting or receiving a recognition signal;

a comparator circuit for comparing said measurement signal to a predetermined optimal transmitter/receiver antenna operation signal; and

control circuitry for controlling the tuning of said transmitter/receiver antenna such that;

(a) in the event that said measurement signal indicates optimal performance of said transmitter/receiver antenna relative to said predetermine optimal transmitter/receiver antenna signal, storing said measurement signal as said predetermined optimal transmitter/receiver antenna operation signal, (b) in the event that said measurement signal indicates less than optimal performance of said transmitter/receiver antenna, generating a tuning signal to antenna tuning circuitry associated with said transmitter/receiver antenna and (c)repeating steps (a) to and (b) until an optimal transmitter/receiver antenna performance condition exists.

2. The improved static antenna tuning measurement apparatus as in claim 1, wherein said antenna voltage conversion circuitry comprises a voltage-to-frequency conversion circuit.

3. The improved static antenna tuning apparatus as in claim 1, wherein said comparator circuit comprises a gate circuit for generating a count signal representative of the analog voltage values from said transmitter/receiver antenna and a counter for counting said count signal;

a maximum value memory for storing said predetermined optimal transmitter/receiver antenna signaland a byte comparator circuit for comparing said connected count signal to said predetermined optimal transmitter/receiver antenna signal.

4. The improved static antenna tuning apparatus as in claim 3, wherein said control circuitry comprises circuitry for generating as control signal to a tuning capacitor driver circuit associated with said transmitter/receiver antenna.

5. The improved static antenna tuning apparatus as in claim 1, wherein said control circuitry comprises a plurality of control instructions associated with a microprocessor for controlling operation of said transmitter/receiver of said recognition system.

6. The improved static antenna tuning apparatus as in claim 1, wherein said control circuitry comprises a counter module for said transmitter/receiver of said recognition system and, further, wherein said antenna voltage conversion circuitry comprises a voltage adaption circuit for generating an adapted voltage and a voltage-to-frequency converter for receiving said adapted voltage and generating a frequency signal representative of said adapted voltage.

7. The improved static antenna tuning voltage measurement apparatus as in claim 1, further comprising circuitry for measuring the analog voltage arising from operation of said antenna transmitter/receiver in a transmit or receive mode of operation.

8. A method for forming an improved antenna tuning apparatus for a transmitter/receiver of a recognition system transmitter/receiver circuit, said recognition system having an associated matching member which operates with a transponder to control a control mechanism of a device;

the matching member and other non-matching members containing facilities each of which, when receiving energy transmitted from said transmitter/receiver antenna produces a respective unique recognition signal in said transponder;

control of the device being possible only upon simultaneous occurrence of both operation of the control mechanism and production of a recognition signal by the matching member;

wherein the method for forming the improved static antenna tuning apparatus comprises the steps of;

forming an antenna voltage conversion circuitry for converting a voltage signal to a measurement signal representative of transmitter/receiver antenna operation, said voltage signal arising from said transmitter/receiver antenna transmitting or receiving a recognition signal;

forming a comparator circuit for comparing said measurement signal to a predetermined optimal transmitter/receiver antenna operation signal; and

forming control circuitry for controlling the tuning of said transmitter/receiver antenna such that;

(a) in the event that said measurement signal indicates optimal performance of said transmitter/receiver antenna relative to said predetermine optimal transmitter/receiver antenna signal, storing said measurement signal as said predetermined optimal transmitter/receiver antenna operation signal and (b) in the event that said measurement signal indicates less than optimal performance of said transmitter/receiver antenna, generating a tuning signal to antenna tuning circuitry associated with said transmitter/receiver antenna; and

(c)repeating steps (a) and (b) until an optimal transmitter/receiver antenna performance condition exists.

9. The method of claim 8, wherein said antenna voltage conversion circuitry forming step further comprises the step of forming a voltage-to-frequency conversion circuit.

10. The method of claim 8, wherein said comparator circuit forming step further comprises the step of forming a gate circuit for generating a count signal representative of the analog voltage values from said transmitter/receiver antenna and a counter for counting said count signal;

a maximum value memory for storing said predetermined optimal transmitter/receiver antenna signaland a byte comparator circuit for comparing said connected count signal to said predetermined optimal transmitter/receiver antenna signal.

11. The method of claim 10, wherein said control circuitry forming step further comprises the step of forming circuitry for generating as control signal to a tuning capacitor driver circuit associated with said transmitter/receiver antenna.

12. The method of claim 8, wherein said control circuitry forming step further comprises the step of forming a plurality of control instructions associated with a microprocessor for controlling operation of said transmitter/receiver of said recognition system.

13. The method of claim 8, wherein said control circuitry forming step further comprises the step of forming a counter module for said transmitter/receiver of said recognition system and, further, wherein said antenna voltage conversion circuitry comprises a voltage adaption circuit for generating an adapted voltage and a voltage-to-frequency converter for receiving said adapted voltage and generating a frequency signal representative of said adapted voltage.

14. The method of claim 8 further comprising the steps of forming circuitry for measuring the analog voltage arising from operation of said antenna transmitter/receiver in a transmit or receive mode of operation.

15. An improved method for tuning a transmitter/receiver antenna of a recognition system transmitter/receiver circuit, said recognition system having an associated matching member which operates with a transponder to control a control mechanism of a device;

the matching member and other non-matching members containing facilities each of which, when receiving energy transmitted from said transmitter/receiver antenna produces a respective unique recognition signal in said transponder;

control of the device being possible only upon simultaneous occurrence of both operation of the control mechanism and production of a recognition signal by the matching member;

wherein the improved static antenna tuning method comprises the steps of;

converting a voltage signal to a measurement signal representative of transmitter/receiver antenna operation, said voltage signal arising from said transmitter/receiver antenna transmitting or receiving a recognition signal;

comparing said measurement signal to a predetermined optimal transmitter/receiver antenna operation signal; and

controlling the tuning of said transmitter/receiver antenna such that;

(a) in the event that said measurement signal indicates optimal performance of said transmitter/receiver antenna relative to said predetermine optimal transmitter/receiver antenna signal, storing said measurement signal as said predetermined optimal transmitter/receiver antenna operation signal and (b) in the event that said measurement signal indicates less than optimal performance of said transmitter/receiver antenna, generating a tuning signal to antenna tuning circuitry associated with said transmitter/receiver antenna; and

(c)repeating steps (a) and (b) until an optimal transmitter/receiver antenna performance condition exists.

16. The method of claim 15, wherein said converting step further comprises the step of converting said voltage signal to a frequency signal representative of transmitter/receiver antenna operation.

17. The method of claim 15 further comprising the steps of generating a count signal representative of the analog voltage values from said transmitter/receiver antenna and a counter for counting said count signal;

storing said predetermined optimal transmitter/receiver antenna signal, and comparing said connected count signal to said predetermined optimal transmitter/receiver antenna signal.

18. The method of claim 15, further comprising the steps of generating as control signal to a tuning capacitor driver circuit associated with said transmitter/receiver antenna.

19. The method of claim 15 further comprising the step of controlling operation of said transmitter/receiver of said recognition system using a plurality of control instructions associated with a microprocessor.

20. The method of claim 15 further comprising the steps of generating an adapted voltage representation of said voltage signal and a voltage-to-frequency converter for receiving said adapted voltage, and generating a frequency signal representative of said adapted voltage.