Signal modulating method, demodulating method and signal modulating apparatus and demodulating apparatus

Abstract

The present invention uses a conversion table a part of which is duplexed in order to directly convert input M-bit data into an N-bit code without using a margin bit. This conversion table comprises first and second sub-tables each including a plurality of code groups, and these code groups contain different codes to the same input data. In the second sub-table, a part of the first sub-table obtaining by allocating different codes to the data ranging from the first input data to the second input data of the sub-table is duplexed. The set of the codes of the duplexed portion of the conversion table is so constituted as to take a digital sum variation of opposite signs, and codes are sequentially allocated to the input data from the code having the greater absolute value of the digital sum variation. In this way, the present invention can appropriately suppress low frequency components of modulation signals.

Description

[0001] This application has an application date of July 7, 1995, a divisional submission date of March 31, 2004, an application number of 200410032439.9, and an invention title of "Signal modulation method, signal modulation device, signal demodulation method, and signal demodulation" Device" is a divisional application of the invention patent application. technical field [0002] The present invention relates to a signal modulation method, a signal modulation device, a signal demodulation method, and a signal demodulation device used when recording or reproducing digital signals such as digital audio signals, digital image signals, and data, for example, on a recording medium. A signal modulation method, a signal modulation device, a signal demodulation method, and a signal demodulation device for an optical disc device dedicated to reproduction, or a recording and reproduction device for a recordable or rewritable optical disc. Background technique [0003] When digital si...

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Problems solved by technology

[0032]However, there are only 3 types of 2-bit boundary bits. In addition, due to limitations such as travel, the boundary bits that can often be inserted are limited to only 1 type

Therefore, in the prior DSV control method, there are many intervals where DSV control cannot be performed. As a result, the low-frequency components of the modulation signal cannot be sufficiently suppressed, which will affect the stability of the servo system and the bit error rate during data demodulation. produce adverse effects

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