Data slicer, data slicing method, and amplitude evaluation value setting method

• US 20060268170A1
• Filed: 08/08/2006
• Published: 11/30/2006
• Est. Priority Date: 07/02/2002
• Status: Active Grant

• Current Assignee: Panasonic Semiconductor Solutions Co., Ltd. (Winbond Electronics Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Suzuki, Akihiro, Kuzumoto, Keiichi
• Granted Patent: US 7,599,003 B2
• Time in Patent Office: Days
• US Class Current: 348/465
• CPC Class Codes: H04N 7/035 Circuits for the digital non-picture data signal, e.g. for slicing of the data signal, for regeneration of the data-clock signal, for error detection or correction of the data signal
• CPC Class Codes: H04N 7/0355 for discrimination of the binary level of the digital data, e.g. amplitude slicers
• CPC Class Codes: H04N 7/0357 for error detection or correction
• CPC Class Codes: H04N 7/0882 for the transmission of character code signals, e.g. for teletext circuits for the digital non-picture data signal H04N7/035

Abstract

A data slicer 300 includes a slice level calculation unit 310 that determines whether a detected digital video signal is a CRI signal on the basis of the amplitude of the signal, and sets a reference slice level and upper and lower slice levels which are obtained by providing offset in the reference slice level, by using only the CRI signal; a data slicing unit 160 that binarizes a digital video signal S140 using the slice levels; a decoding circuit 170 that converts binarized serial data into parallel data; and a data selection unit 320 that selects data including no error from the decoded data, and outputs the selected data through a video signal output terminal 190. Therefore, even when the video signal is distorted, this data slicer can set appropriate slice level data to binarize the video signal, thereby suppressing the occurrence rate of decoding errors.

Claims

1-4. -4. (canceled)

5. A data slicer comprising;

an A/D conversion unit for converting an input signal including a reference waveform of a predetermined cycle and amplitude, into a digital signal;

a reference cycle detection unit for determining whether a cycle of the digital signal is the cycle of the reference waveform or not;

a maximum/minimum retrieval unit for retrieving maximum and minimum values of the digital signal;

an amplitude evaluation unit for determining whether an amplitude of the digital signal, which is calculated from the retrieved maximum and minimum values, is the amplitude of the reference waveform or not;

a slice level data calculation unit that employs an average value of the digital signal, which is calculated from the maximum and minimum values when detecting the cycle and amplitude of the reference waveform, as slice level data; and

a binarization unit for binarizing the digital signal into the slice level data, to be converted into a binarized signal.

6. The data slicer of claim 5 wherein:

the maximum/minimum retrieval unit retrieves maximum and minimum values of the digital signal in each cycle, and

the amplitude evaluation unit determines whether the amplitude calculated from the maximum and minimum values in each cycle is the amplitude of the reference waveform or not.

7. The data slicer of claim 5 wherein

when calculating the average value from the maximum and minimum values, the slice level calculation unit carries out an averaging process for the calculated average and the slice level data that has been calculated in a previous cycle, and updates the slice level data on the basis of the obtained average.

8. The data slicer of claim 5 wherein

the reference waveform and the data signal correspond to a signal of character broadcast which is transmitted being superimposed upon a vertical blanking interval of a video signal.

9-18. -18. (canceled)

19. An amplitude evaluation value setting method comprising:

a start value setting step of setting a start value at an amplitude evaluation value for determining whether an input signal including data which are transmitted in serial is a desired signal or not;

a signal detection step of evaluating an amplitude of the input signal on the basis of the amplitude evaluation value in a predetermined period, thereby detecting the desired signal;

a slice level data calculation step of, when detecting the desired signal, calculating slice level data for binarizing the input signal, on the basis of the detected desired signal;

a binarization step of binarizing the input signal using the slice level data, to be converted into a binarized signal;

a decoding step of decoding serial data which are extracted from the binarized signal, thereby generating decoded data;

an error count step of counting errors in the decoded data, and storing the amplitude evaluation value and the number of errors;

an amplitude evaluation value update step of binarizing and decoding the input signal and counting errors in the decoded data during a predetermined period, thereafter subjecting the amplitude evaluation value to an arithmetic process using a predetermined step value, so as to approach an end value, and updating the amplitude evaluation value; and

an amplitude evaluation value selection step of selecting an amplitude evaluation value that minimizes the number of errors as an optimum amplitude evaluation value, on the basis of the numbers of errors at various amplitude evaluation values, which are obtained by changing the amplitude evaluation value in the predetermined step value from the start value to the end value.