Granted Patent B2

US 7,289,584 · App. 10/460,401 · Granted Oct 30, 2007

Abstract

Claims (36)

1. A method for decoding data comprising:

receiving data symbols on first and second channels;

detecting data symbol level transitions for each channel;

predicting a period of a next pulse;

verifying the validity of data symbols on each channel; and

selecting the best data symbol from one of the two channels.

2. The method of claim 1 , wherein the step of predicting a future level transition comprises predicting the time period of a future data symbol by using known periods of previously selected symbols.

3. The method of claim 1 , wherein the step of verifying symbol validity is conducted by pattern matching the symbols received on each channel with a known symbol pattern.

4. The method of claim 1 , wherein the step of selecting the best data symbol comprises:

measuring the symbol period of each received valid symbol;

comparing the measured period with a predicted period; and

choosing the channel carrying the symbol with a symbol period closest to the predicted period.

5. The method of claim 1 , wherein the step of selecting the best data symbol comprises:

applying least squares time pattern recognition in selecting the best data symbol based on where level transitions are expected to occur.

6. The method of claim 4 , wherein the step of choosing the best data symbol comprises selecting a data symbol having a minimum distance to a predicted symbol period.

7. The method of claim 1 , further comprising:

weighing in information from the channel having the best data symbol with stored data topredict a next symbol period.

8. The method of claim 7 , wherein the step of weighing in information comprises:

predicting the next symbol period according to the formula:

Y k =αU k +(1−α) Y k−1

wherein Y k is a present output used as a next predicted symbol period, the Y k being a weighted average period of present and past inputs;

Y k−1 is a past output used as the predicted present symbol period, Y k−1 being a last weighted average;

α is a filter weigh factor; and

U k is present input symbol period.

9. The method of claim 8 , wherein the output Y k−1 is used to compare between present input periods U a and U b , corresponding to the first and second channels, using the following logic:

If | Y k−1 −U ak |<|Y k−1 −U bk |, then

Y k =αU ak +(1−α) Y k−1

Else,

Y k =αU bk +(1−α) Y k−1

wherein the present input period U ak or U bk is chosen based upon which of the two has a period closest to the last weighted average Y k−1 , the input period U ak or U bk that is closest is chosen as the U k to compute the present weighted average Y k .

10. The method of claim 1 , wherein the step of verifying the validity of data symbols comprises:

establishing a detection time window;

determining a valid zero symbol when a first number of level transitions are detected during that time window; and

determining a valid one symbol when a second number of level transitions are detected during that time window.

11. The method of claim 10 , wherein the first number of transitions is two.

12. The method of claim 10 , wherein the second number of transitions is one.

Assignments (6)