Slice level control circuit

Abstract

An analog input signal 1a is made to be a C cut RF signal 5a in which a DC component is cut and a DC level is adjusted by a capacitor 2, a resistor 3, and a resistor 4 being connected in series, and voltage applied to one end of the resistor 4. A comparator 6 compares the C cut RF signal 5a with 5b and generates a binarization RF signal 7 being binarization output (binarization data), and the binarization RF signal 7 drives a charge pump circuit 8. An output in which a high frequency component is removed by an analog low pass filter 10 is converted to a digital value for each sampling period by an A / D converter circuit 11, the prescribed filter processing is performed by a digital filter 12, and converted to analog voltage by a D / A converter 13. A slice level of a binarization circuit is controlled by analog voltage outputted from the D / A converter 13.

Description

technical field [0001] The present invention relates to a clipping level control circuit used in CD, DVD and other optical disc reproducing devices. Background technique [0002] The data recorded on the optical disc has a high level period (H period) and a low level period (L period) that are equally long when viewed over a long period of time. The slice level control circuit is a circuit that controls the slice level of the input signal of such data so that the H interval and the L interval of the sliced ​​data are the same length. [0003] The configuration of a conventional slice level control circuit will be described with reference to FIG. 5 . In the conventional slice level control circuit, an analog input signal read from an optical disk is input as a positive phase signal 1a and a reverse phase signal 1b. The so-called positive phase signal 1a and reverse phase signal 1b are analog input signals with the same amplitude but opposite phases. The analog input signal...

AI Technical Summary

Problems solved by technology

Furthermore, when the jitter of the data rate recorded on the optical disk fluctuates greatly and it is desired to ease the tracking of the analog filter 9 to ensure stability, or to optimize the fault characteristics according to the restoration speed and improve the projection capability, etc., there may be Problems Difficult to Change to Optimum Filtering Characteristics

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