Detector tolerant of frequency misalignment

• US 6,452,986 B1
• Filed: 05/17/1999
• Issued: 09/17/2002
• 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, Luxford, Gregory Vincent
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): Nguyen, Dung X.
• Application Number:
  US09/313,125
• Time in Patent Office: 1,219 Days
• Field of Search: 375/376, 375/375, 375/135, 375/136, 375/142, 375/145, 375/253, 375/371, 375/316, 375/149, 375/150, 375/151, 375/260, 375/349, 375/327, 375/354, 375/343, 455/137, 455/139, 455/147, 455/190.1, 340/870.02, 340/870.03, 340/870.4, 340/855.3, 329/325, 327/145, 327/147, 327/154, 327/156
• US Class Current: 375/343
• CPC Class Codes: H03L 7/093 using special filtering or amplification characteristics in the loop H03L7/087 - H03L7/091 take precedence
• CPC Class Codes: H03L 7/0994 comprising an accumulator
• CPC Class Codes: H04J 1/05 using digital techniques
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26

Abstract

A method to separate data transmitted in parallel at arbitrary frequencies within a channel includes: separating a signal from one channel into a plurality of bins representing sub-channels, each bin having a bin frequency; generating a locked frequency by applying a phase locked loop (PLL) to each sub-channel; determining a difference between the locked frequency and the bin frequency; and correlating the signal with a difference between the locked frequency and the bin frequency.

Claims

1. A method to separate data transmitted in parallel at arbitrary frequencies within a channel, comprising:

separating a signal from one channel into a plurality of bins representing sub-channels, each bin having a bin frequency;

generating a locked frequency by applying a phase locked loop (PLL) to each sub-channel;

determining a difference between the locked frequency and the bin frequency; and

correlating the signal with a difference between the locked frequency and the bin frequency.

2. The method of claim 1, wherein the bin has a center frequency representation, further comprising comparing the signal with the center frequency representation.

3. The method of claim 1, wherein the bin has a low frequency representation, further comprising comparing the signal with the low frequency representation.

4. The method of claim 1, wherein the bin has a high frequency representation, further comprising comparing the signal with the high frequency representation.

5. The method of claim 1, wherein the bin has a center frequency representation, a low frequency representation, and a high frequency representation, further comprising:

determining a difference between the locked frequency and the center frequency representation; and

if the difference is less than a predetermined value, comparing the signal with the center frequency representation.

6. The method of claim 5, further comprising comparing the signal with the low frequency representation if the low frequency representation is greater than the locked frequency representation.

7. The method of claim 5, further comprising comparing the signal with the locked frequency representation if the low frequency representation is less than the locked frequency representation.

8. The method of claim 5, wherein the predetermined value is approximately 0.5 of the bin spacing.

9. The method of claim 1, further comprising recovering the data from the correlated signal.