Methods and systems for decoding data

1. A method, comprising:

receiving a coded bit stream that is encoded using a Non Return to Zero Inverted (NRZI) code and a 17 Parity Preserve/Prohibit (17PP) code;

determining a 17PP modulated bit stream based upon the coded bit stream using a first selected decoding method; and

generating a plurality of decisions by processing the 17PP modulated bit stream using a second selected decoding method,

wherein the received coded bit stream comprises a plurality of coded bits, and the plurality of decisions are estimates of a plurality of source bits in a source information.

2. The method of claim 1 , further comprising selecting the first selected decoding method and the second selected decoding method based upon at least one of a plurality of parameters associated with the received coded bit stream.

3. The method of claim 2 , wherein the plurality of operating conditions comprise a Signal to Noise Ratio (SNR) of the received coded bit stream, a type of noise in the received coded bit stream, a medium of storage used for storing the coded bits, or combinations thereof.

4. The method of claim 3 , wherein the type of the noise comprises optical noise and electrical noise.

5. The method of claim 1 , wherein the first selected decoding method comprises a Non Return to Zero Inverted (NRZI) decoding method.

6. The method of claim 5 , wherein the NRZI decoding method comprises a Bahl, Cocke, Jelinek, and Raviv (BCJR) method, a hypothesis test method, or an analog XOR method.

7. The method of claim 1 , wherein the second selected decoding method comprises a 17PP decoding method.

8. The method of claim 7 , wherein the 17PP decoding method comprises a Bahl, Cocke, Jelinek, and Raviv (BCJR) method, or a threshold based Naïve method.

9. The method of claim 1 , wherein the first selected decoding method and the second selected decoding method comprises a Maximum A-posteriori Probability (MAP) decoding method.

10. The method of claim 1 , wherein the first selected decoding method comprises: initializing a first prior probability equal to 0.5 of a bit that has a numeric value equal to ‘0’, and a second prior probability equal to 0.5 of a bit that has a numeric value equal to ‘1’.

11. The method of claim 1 , wherein the first selected decoding method comprises: initializing a prior probability equal to 0.7 of a bit that has a numeric value equal to ‘0’, and a second prior probability equal to 0.3 of a bit that has a numeric value equal to ‘1’.

12. The method of claim 1 , wherein the first selected decoding method is based on a Gaussian Channel model.

13. The method of claim 1 , wherein the second selected decoding method comprises a threshold based method.

14. The method of claim 13 , wherein the threshold based method comprises: selecting a threshold based upon electrical noise energy and optical noise energy in the received coded bit stream.

15. The method of claim 1 , wherein the second selected decoding method comprises determining the source information based upon a look up table.

16. A decoding method, comprising:

receiving a coded bit stream that is encoded using a Non Return to Zero Inverted (NRZI) code and a 17 Parity Preserve/Prohibit (17PP) code;

selecting a combination of a NRZI decoding method and a 17PP decoding method from a plurality of NRZI decoding methods and a plurality of 17PP decoding methods, respectively based upon a plurality of operating conditions;

determining a 17PP modulated bit stream based upon the coded bit stream using the NRZI decoding method; and

determining source information based upon the 17PP modulated bit stream using the 17PP decoding method.

17. The method of claim 16 , wherein the combination of a NRZI decoding method and a 17PP decoding method comprises a Analog XOR method-Naïve method combination, a Hypothesis test method-Naïve method combination, a BCJR method-Naïve method combination, a Hypothesis method-BCJR method combination and a BCJR method-BCJR method combination.

18. A system comprising;

a data storage device that stores a coded bit stream that is encoded using a Non Return to Zero Inverted (NRZI) code and a 17 Parity Preserve/Prohibit (17PP) code;

a processing system that is in an operational communication with the data storage device, wherein the processing system is configured to:

determine a 17PP modulated bit stream based upon the coded bit stream using an NRZI decoder; and

generate a plurality of decisions by processing the 17PP modulated bit stream using a 17PP decoder,

wherein the coded bit stream comprises a plurality of coded bits, and the plurality of decisions are estimates of a plurality of source bits in a source information.

19. The system of claim 18 , wherein the data storage device comprises an optical storage device, an optical disk, or a universal serial bus (USB) device.

20. The system of claim 18 , further comprising an output device that outputs the source information in a determined format.

21. The system of claim 20 , wherein the output device comprises a display device, an audio device, a printer, or combinations thereof.

22. The system of claim 18 , wherein the processing system comprises a decoder, an optical disk reader, a digital versatile disk player, a compact disk player.

23. A system comprising;

a data storage device that stores a coded bit stream that is encoded using a Non Return to Zero Inverted (NRZI) code and a 17 Parity Preserve/Prohibit (17PP) code;

a processing system that is in an operational communication with the data storage device, wherein the processing system is configured to:

determine a 17PP modulated bit stream based upon the coded bit stream using a Hypothesis test decoding method; and

generate a plurality of decisions by processing the 17PP modulated bit stream using a Naive decoding method,

wherein the coded bit stream comprises a plurality of coded bits, and the plurality of decisions are estimates of a plurality of source bits in a source information.

24. A system, comprising;

a data storage device that stores a coded bit stream that is encoded using a Non Return to Zero Inverted (NRZI) code and a 17 Parity Preserve/Prohibit (17PP) code;

a processing system that is in an operational communication with the data storage device, wherein the processing system is configured to:

determine a 17PP modulated bit stream based upon the coded bit stream using a Hypothesis test decoding method; and

generate a plurality of decisions by processing the 17PP modulated bit stream using a BCJR method,

wherein the coded bit stream comprises a plurality of coded bits, and the plurality of decisions are estimates of a plurality of source bits in a source information.

25. A communication system comprising:

an encoder generating a coded bit stream that is encoded using a Non Return to Zero Inverted (NRZI) code and a 17 Parity Preserve/Prohibit (17PP) code;

a decoder that receives the coded bit stream via a communication channel, wherein the decoder is configured to:

determine a 17PP modulated bit stream based upon the received coded bit stream using an NRZI decoder; and

generate a plurality of decisions by processing the 17PP modulated bit stream using a 17PP decoder,

wherein the coded bit stream comprises a plurality of coded bits, and the plurality of decisions are estimates of source bits in a source information.