Data conversion apparatus

Abstract

An apparatus for converting source data into modulation data includes a compressed look-up table based on a conversion correlation, a non-effective data discriminator, a group discriminator, an output flag generator, a flag modulator, a control signal generator and an output compensator. A first address having the source data and a original input flag and a second address having the source data and a modulated input flag are sequentially applied to the look-up table which in turn generates first tentative data and a first tentative flag with respect to the first address, generates second tentative data and a second tentative flag with respect to the second address, and produces unique non-effective data when non-effective data is applied. The group discriminator produces a group discrimination signal based on the source data, the non-effective data discriminator produces a non-effective data detection signal when the first tentative data is non-effective data, the output flag generator produces an output flag based on one of the tentative flags and the non-effective data detection signal, and the flag modulator sequentially produces the original input flag and the moduated input flag based on the non-effective data detection signal and output of the output flag generator. The control signal generator produces a control signal based on the non-effective data detection signal and the group discrimination signal. The output compensator produces the modulation data, by modulating the second tentative data in accordance with the control signal.

Dependencies are inferred from the claim text.