Data Slicer Having An Error Correction Device

• US 20090044087A1
• Filed: 11/22/2007
• Published: 02/12/2009
• Est. Priority Date: 08/09/2007
• Status: Active Grant

• Current Assignee: Novatek Microelectronics Corporation (Novatek Microelectronics Corp Limited)
• Original Assignee: Novatek Microelectronics Corporation (Novatek Microelectronics Corp Limited)
• Inventors: Chiou, Ting, Chen, Chieh-Cheng, Wang, Ho-Lin
• Granted Patent: US 7,992,077 B2
• Time in Patent Office: Days
• US Class Current: 714/800
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0063 Single parity check
• CPC Class Codes: H04L 25/06 Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection
• CPC Class Codes: H04L 25/08 Modifications for reducing interference; Modifications for reducing effects due to line faults ; Receiver end arrangements for detecting or overcoming line faults

Abstract

A data slicer includes an error bit predictor, a DC level compensator, a co-channel detector, and an output device. The data slicer generates four bytes according to four slicing levels respectively. The four slicing levels are a DC level, a level generated by adding a predetermined offset to the DC level, a level generated by subtracting the predetermined offset from the DC level, and a compensated level generated by the DC level compensator. The co-channel detector determines if the compensated level has the co-channel interference. The output device generates an output byte according to indication signals generated by the co-channel detector and the error bit predictor and the parity check of the four bytes.

Claims

1. A data slicer having an error correction device comprising:

a first subtractor, for subtracting a first level signal from a first data signal to generate a second data signal;

a first serial to parallel converter, coupled to the first subtractor, for generating a first byte according to a sign bit of the second data signal;

a level compensator, coupled to the first subtractor, for adjusting an offset of the first level signal according to the second data signal to generate a second level signal;

a first comparator, coupled to the level compensator, for comparing the second level signal with the first data signal to generate a first comparing signal;

a second serial to parallel converter, coupled to the first comparator, for converting the first comparing signal to a second byte;

a co-channel detector, coupled to the level compensator, for determining co-channel interference according to a difference between a maximum and a minimum of the second level signal to generate a first indication signal;

an error bit predictor, coupled to the first subtractor, for indicating an error bit of the first byte to generate a second indication signal; and

an output device, for outputting the first byte or the second byte according to the first indication signal, a parity check of the first byte, and a parity check of the second byte, or outputting a corrected first byte according to the second indication signal.

2. The data slicer of claim 1 further comprising:

a first adder, for adding a predetermined offset to the first level signal;

a second comparator, coupled to the first adder, for comparing an output signal of the first adder with the first data signal to generate a second comparing signal;

a third serial to parallel converter, coupled to the second comparator, for converting the second comparing signal to a third byte;

a second subtractor, for subtracting the predetermined offset from the first level signal;

a third comparator, coupled to the second subtractor, for comparing an output signal of the second subtractor with the first data signal to generate a third comparing signal; and

a fourth serial to parallel converter, coupled to the third converter, for converting the third comparing signal to a fourth byte.

3. The data slicer of claim 2 wherein the output device outputs the first byte, the second byte, the third byte, or the fourth byte according to the first indication signal, the parity check of the first byte, the parity check of the second byte, a parity check of the third byte, and a parity check of the fourth byte, or outputs the corrected first byte according to the second indication signal.

4. The data slicer of claim 1 wherein the level compensator comprises:

a first filter, for filtering bits determined to be 1 from the second data signal;

a second filter, for filtering bits determined to be 0 from the second data signal;

an averaging unit, coupled to the first filter and the second filter, for calculating an average value of output signals of the first filter and the second filter; and

a second adder, coupled to the averaging unit, for adding an output signal of the averaging unit to the first level signal to generate the second level signal.

5. The data slicer of claim 1 wherein the co-channel detector comprises:

a third filter, for filtering a maximum of the second level signal;

a fourth filter, for filtering a minimum of the second level signal;

a third subtractor, coupled to the third filter and the fourth filter, for subtracting the minimum of the second level signal from the maximum of the second level signal;

a fourth comparator, coupled to the third subtractor, for comparing an output signal of the third substractor with a first threshold;

a counter, coupled to the fourth comparator, for increasing a count value of the counter when the output signal of the third subtractor is larger than the first threshold; and

a fifth comparator, coupled to the counter, for comparing the count value of the counter with a second threshold to output the first indication signal.

6. The data slicer of claim 1 further comprising:

a Phase Lock Loop (PLL), for generating a sampling clock signal;

a re-sampling unit, coupled to the PLL and the first subtractor, for re-sampling an image signal according to the sampling clock signal to generate the first data signal; and

a level estimator, coupled to the first subtractor, for generating the first level signal according to the image signal.

7. The data slicer of claim 1 wherein the first data signal is a Vertical Blanking Interval (VBI) data signal.

8. The data slicer of claim 1 wherein the first level signal is DC level signal.

9. A data slicer having an error correction device comprising:

a first subtractor for subtracting a first level signal from a first data signal to generate a second data signal;

a first serial to parallel converter coupled to the first subtractor for generating a first byte according to a sign bit of the second data signal;

a first adder, for adding a predetermined offset to the first level signal;

a first comparator, coupled to the first adder, for comparing an output signal of the first adder with the first data signal to generate a first comparing signal;

a second serial to parallel converter, coupled to the first comparator, for converting the first comparing signal to a second byte;

a second subtractor, for subtracting the predetermined offset from the first level signal;

a second comparator, coupled to the second subtractor, for comparing an output signal of the second subtractor with the first data signal to generate a second comparing signal;

a third serial to parallel converter, coupled to the second comparator, for converting the second comparing signal to a third byte;

an error bit predictor, coupled to the first subtractor, for indicating an error bit of the first byte to generate a first indication signal; and

an output device, for outputting the first byte, the second byte, or the third byte according to a parity check of the first byte, a parity check of the second byte, and a parity check of the third byte, or outputting a corrected first byte according to the first indication signal.

10. The data slicer of claim 9 further comprising:

a PLL, for generating a sampling clock signal;

a re-sampling unit, coupled to the PLL and the first subtractor, for re-sampling an image signal according to the sampling clock signal to generate the first data signal; and

a level estimator, coupled to the first subtractor, for generating the first level signal according to the image signal.

11. The data slicer of claim 9 wherein the first data signal is a VBI data signal.

12. The data slicer of claim 9 wherein the first data signal is a DC level signal.