Receiver capable of parallel demodulation of messages

• US 6,181,258 B1
• Filed: 05/17/1999
• Issued: 01/30/2001
• Est. Priority Date: 05/17/1999
• Status: Expired due to Term

• Current Assignee: Landis+Gyr Innovations Incorporated (Landis+Gyr Group AG)
• Original Assignee: CellNet Data Systems, Inc. (Landis+Gyr Group AG)
• Inventors: Irving, Clive Russell, Summers, Andrew Gordon, Luxford, Gregory Vincent
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): Edwards, Jr., Timothy
• Application Number:
  US09/312,928
• Time in Patent Office: 624 Days
• Field of Search: 340/870.28, 340/870.18, 340/870.02, 340/825.72, 370/208, 370/210, 375/316, 375/327, 455/352, 455/334
• US Class Current: 340/870.28
• CPC Class Codes: H03D 7/163 the local oscillations of at least two of the frequency changers being derived from a single oscillator
• CPC Class Codes: H04B 1/0025 using a sampling rate lower than twice the highest frequency component of the sampled signal for demodulation of angle-modulated signals H03D3/006
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04L 7/04 Speed or phase control by synchronisation signals H04L7/0075 takes precedence

Abstract

A receiver which is capable of receiving in parallel data transmitted at arbitrary frequencies within a radio channel includes: a radio frequency (RF) front end to convert an RF signal to a digitized signal; a Fast Fourier Transform (FFT) generator coupled to the RF front-end to separate the digitized signal into a plurality of sub-channels; a bank of phase locked loops (PLLs) coupled to the FFT generator, each PLL operating on a sub-channel with a sub-channel center; and a flag detector coupled to the bank of PLLs to detect variations from the sub-channel center and to recover the usage data transmitted from the end-point.

Claims

1. A receiver to collect usage data from an end-point, the receiver capable of receiving in parallel data transmitted at arbitrary frequencies within a radio channel, comprising:

a radio frequency (RF) front end to convert an RF signal to a digitized signal;

a Fast Fourier Transform (FFT) generator coupled to the RF front-end to separate the digitized signal into a plurality of sub-channels;

a bank of phase locked loops (PLLs) coupled to the FFT generator, each PLL operating on a sub-channel with a sub-channel center; and

a flag detector coupled to the bank of PLLs to detect variations from the sub-channel center and to recover the usage data transmitted from the end-point.

2. The receiver of claim 1, further comprising a second RF front end coupled to the FFT generator to convert a diversity RF signal to an intermediate frequency and to digitize the intermediate frequency.

3. The receiver of claim 2, further comprising a multiplexer coupled to the RF front ends.

4. The receiver of claim 1, further comprising a decimator coupled to the RF front-end and the FFT generator.

5. The receiver of claim 4, further comprising a mixer coupled to the decimator.

6. The receiver of claim 1, wherein the FFT generator produces a stream of values representing a plurality of band pass filters.

7. The receiver of claim 6, wherein data is transferred at a bit rate and wherein each band pass filter has a center which is spaced by one half the bit rate.

8. The receiver of claim 1, wherein the PLL has a PLL frequency, wherein each sub-channel has a bin frequency, and wherein the flag detector determines a difference between the PLL frequency and the bin frequency.

9. The receiver of claim 8, wherein each bin spacing separates one bin from an adjacent bin and wherein the flag detector correlates the digitized signals of each sub-channel against a first flag sequence if the difference is less than the bin spacing.

10. The receiver of claim 8, wherein each bin spacing separates one bin from an adjacent bin and wherein the flag detector correlates the digitized signals of each sub-channel against a second flag sequence if the difference is greater than the bin spacing.

20. The receiver of claim 8, wherein each bin spacing separating one bin from an adjacent bin and wherein the flag detector correlates the digitized signals of each sub-channel against a second flag sequence if the difference is greater than the bin spacing.

11. A remote data collection system to collect usage data from an end-point, comprising:

a monitoring module coupled to the end-point, the monitoring module having a wireless transmitter to transmit the usage data;

a remote receiver coupled to the wireless transmitter, including;

a radio frequency (RF) front end to convert an RF signal to a digitized signal;

a Fast Fourier Transform (FFT) generator coupled to the RF front-end to separate the digitized signal into a plurality of sub-channels;

a bank of phase locked loops (PLLs) coupled to the FFT generator, each PLL operating on a sub-channel with a sub-channel center; and

a flag detector coupled to the bank of PLLs to detect variations from the sub-channel center and to recover the usage data transmitted by the end-point.

12. The remote data collection system of claim 11, further comprising a second RF front end coupled to the FFT generator to convert a diversity RF signal to an intermediate frequency and to digitize the intermediate frequency.

13. The remote data collection system of claim 12, further comprising a multiplexer coupled to the first and second RF front ends.

14. The remote data collection system of claim 11, further comprising a decimator coupled to the RF front-end and the FFT generator.

15. The remote data collection system of claim 14, further comprising a mixer coupled to the decimator.

16. The remote data collection system of claim 11, wherein the FFT generator produces a stream of values representing a plurality of band pass filters.

17. The remote data collection system of claim 16, wherein data is transferred at a bit rate and wherein each band pass filter has a center which is spaced by one half the bit rate.

18. The remote data collection system of claim 11, wherein the PLL has a PLL frequency, wherein each sub-channel has a bin frequency, and wherein the flag detector determines a difference between the PLL frequency and the bin frequency.

19. The remote data collection system of claim 18, wherein each bin spacing separating one bin from an adjacent bin and wherein the flag detector correlates the digitized signals of each sub-channel against a first flag sequence if the difference is less than the bin spacing.