KR0136922B1 - Modulating and demodulating apparatus of digital vcr - Google Patents

Abstract

The present invention relates to a DVCR, and more particularly, to a modulation and demodulation apparatus for a DVCR that is directed to a data reconstruction characteristic by varying and modulating / demodulating a mapping table according to image data input to the DVCR.

As described above, the DVCR modulation and demodulation device is a device for recording / reproducing video data composed of unit blocks having a specific size. The mapping table is variable by analyzing data of all blocks output through error correction and formatting. Whenever a block start signal is input by varying a mapping table value by a data analysis unit for outputting information, a block start signal generation unit for outputting a unit block start signal of input data, and mapping table variable information of the data analysis unit A mapping table variable output unit for outputting, a ROM storing general mapping table values and modulating or demodulating data of a first unit block using a plurality of unit blocks having a specific length as one unit, and the mapping table variable output unit A plurality of unit blocks having a mapping table value that is varied for each unit block by a negative output signal RAM that modulates or demodulates data of blocks except the first unit block as one unit, and a plurality of consecutive unit blocks are divided at predetermined intervals so that the data of the first unit block at every interval is modulated or The demodulator switches to be outputted, and the other unit block includes an input and output switching unit for switching to be modulated or demodulated by the RAM and outputted.

Description

DVR modulation and demodulation device

1 is a block diagram of a general DVCR recording / reproducing system

2 is a table showing an example of data modulation in a general DVCR.

3 is a block diagram of the modulation apparatus of the DVCR according to the present invention.

4 is a data format diagram according to modulation of the DVCR of the present invention.

5 is a block diagram of a demodulation device for DVCR according to the present invention.

6 is a data format diagram according to demodulation of a DVCR of the present invention.

* Description of the symbols for the main parts of the drawings *

30, 50: input switching unit 31, 51: ROM

32, 52: data analysis unit

33, 53: block start signal generator

34, 54: mapping table variable output

35, 55: RAM

36, 56: output switching unit

The present invention relates to a digital VCR of the present invention, and more particularly, to a modulation and demodulation device for a DVCR having improved data reconstruction characteristics by varying and demodulating a mapping table according to image data input to a DVCR. It is about.

Hereinafter, a recording / reproducing system of a general DVCR will be described with reference to the accompanying drawings.

FIG. 1 is a block diagram of a general DVCR recording / reproducing system, and FIG. 2 is a table showing an example of data modulation in a general DVCR.

A general DVCR recording system includes an interface 1 for converting externally input data into a signal form suitable for the system, and a parity code for error correction in the output data of the interface 1. An error correction / formatting unit (2) for formatting the data into a recording form, a modulation unit (3) for modulating the output data of the error correction / formatting unit (2) with a suitable code for recording on a tape; It consists of a recording AMP 4 for amplifying and outputting the modulated data to a predetermined level so that the output signal of the recording AMP 4 is recorded on the tape via R / T (Rotary Trans) and the recording head.

The reproduction system of the DVCR reproduces a reproduction head for detecting data recorded on the tape, a reproduction AMP 5 for amplifying the detected signal, and an output signal of the reproduction AMP 5 for play back and distortion. A play back / equalizer 6 for correcting phase distortion, a clock restorer 7 for restoring a clock from data restored by the play / equalizer 6, A synchronous detection and demodulation unit 8 for detecting a clock signal from the clock restored data and synchronizing the clock signal with the clock signal; and an error correction / decoding for correcting and deformatting an error of the demodulated signal. It consists of a formatting unit 9 and an interface 10 which is a connection device for outputting the deformatted signal to the outside.

Data modulation in such a DVCR recording / reproducing system is as in FIG.

First, ① in FIG. 2 divides one byte of input data into two parts A and B by 4 bits.

And ② inverts B (b ₁ , b ₂ , b ₃ , b ₄ ) part of ①. _{1 2 3 4 1 2 3 4 1 2 3 k k + 1} ⁸ _{1 2 3 k k + 1 1 1 1 1 1 1 2 2} ^{-3 -10} _{1 2 3 k1 k + 1 1 1 2 2 i i}

Claims (2)

A unit block of a specific size is a device for recording / reproducing the configured image data, comprising: a data analyzer for analyzing data of all blocks output through an error correction and formatting process and outputting mapping table variable information; A block start signal generator for outputting a unit block start signal of input data; A mapping table variable output unit for varying a mapping table value according to mapping table variable information of the data analysis unit and outputting each time a block start signal is input; A ROM which stores general mapping table values and modulates or demodulates data of a first unit block by using a plurality of unit blocks having a specific length as one unit; A RAM having a mapping table value that is varied for each unit block by an output signal of the mapping table variable output unit and modulating or demodulating data of blocks except for the first unit block by using a plurality of unit blocks as one unit; A plurality of consecutive unit blocks are divided at predetermined intervals so that data of the first unit block of each interval is switched so as to be modulated or demodulated by the ROM, and other unit blocks are modulated or demodulated by the RAM and outputted. Modulation and demodulation device of the DVCR characterized in that it comprises an input, output switching unit for switching. 2. The apparatus as claimed in claim 1, wherein an inverse mapping table value is stored in a ROM or a RAM during demodulation.