Transmitter and a method for transmitting data

• US 7,978,073 B2
• Filed: 08/26/2004
• Issued: 07/12/2011
• Est. Priority Date: 12/24/1997
• Status: Active Grant

• Current Assignee: SATO Holdings Corporation
• Original Assignee: Magellan Technology Pty. Ltd (SATO Holdings Corporation)
• Inventors: Littlechild, Stuart Colin, Murdoch, Graham Alexander Munro
• Primary Examiner(s): POPE, DARYL C
• Application Number:
  US10/927,957
• Publication Number:
  US 20060022797A1
• Time in Patent Office: 2,511 Days
• Field of Search: 340/505, 340/539.1, 340/825.69, 340/825.71, 340/825.73, 340/825.77
• US Class Current: 340/572.1
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: H03C 3/00 Angle modulation H03C5/00, H03C7/00 take precedence

Abstract

An excitation reference source (F_C) is split through a 90 degree splitter. One output from the splitter is fed to the LO port of a mixer. Data is fed to the mixer'"'"'s IF port and causes PRK modulation of the LO port'"'"'s signal. The output of the mixer at the RF port is a PRK modulated quadrature signal. This is attenuated and added back onto the reference by a zero degree combiner ready for transmission to the transponder.

Claims

1. A device adapted to receive a modulated signal and derive therefrom a data signal, the device comprising:

an antenna adapted to receive the modulated signal and, in response thereto, produce a first signal;

means for deriving, from the first signal, a local oscillator signal;

means for deriving a second signal by passing a further portion of the first signal through a delay means; and

wherein the local oscillator signal and the second signal are used to demodulate the first signal and obtain an indicative data signal.

2. The device as claimed in claim 1, wherein a phase locked loop is used to derive the local oscillator signal.

3. The device as claimed in claim 2, wherein the phase locked loop is a low loop bandwidth phase locked loop.

4. The device as claimed in claim 1, wherein a mixer is used in demodulating the first signal.

5. The device as claimed in claim 1, wherein a multiplier is used in demodulating the first signal.

6. The device as claimed in claim 1, wherein the first signal is used as a source of power for the device means.

7. The device as claimed in claim 1, wherein the device is a Radio Frequency Identification Device.

8. The device as claimed in claim 1, wherein the device is a passive device.

9. The device as claimed in claim 1, wherein the device is a transponder.

10. A method of demodulating a modulated signal received by a device and deriving therefrom a data signal, the method comprising the steps of:

receiving the modulated signal and producing a first signal;

deriving, from the first signal, a local oscillator signal;

deriving a second signal by passing a further portion of the first signal through a delay means; and

demodulating the first signal using the local oscillator signal and the second signal to obtain an indicative data signal.

11. The method as claimed in claim 10, wherein a phase locked loop is used to derive the local oscillator signal.

12. The method as claimed in claim 11, wherein the phase locked loop is a low loop bandwidth phase locked loop.

13. The method as claimed in claim 10, wherein a mixer is used in demodulating the first signal.

14. The method as claimed in claim 10, wherein a multiplier is used in demodulating the first signal.

15. The method as claimed in claim 10, wherein a low pass filter is used to filter out high frequency signal components and pass the demodulated data signal.

16. The method as claimed in claim 10, wherein the first signal is used as a source of power for the device.

17. A method of demodulating a modulated signal received by a device and deriving there from a data signal, the method comprising the steps of:

receiving the modulated signal and inducing into an antenna of the device, an antenna voltage signal;

amplifying the antenna signal;

providing a portion of the amplified signal to a phase locked loop to filter off sidebands and creating a first signal;

passing another portion of the amplified signal through a delay means and creating a second signal; and

XORing the first and second signals to provide indicative data.

18. The method as claimed in claim 17, wherein the antenna signal is amplified by squaring the signal by a Schmitt trigger device.

19. The method as claimed in claim 17, wherein the phase locked loop is a low bandwidth phase locked loop device.

20. The method as claimed in claim 17, wherein the data is detected using a floating point comparator device.