Base-band encoding apparatus and frequency modulation method using the same in digital broadcasting system

摘要

A baseband encoding apparatus and frequency modulation method using the same in vestigial sideband (VSB) transmission system is disclosed. The apparatus includes a trellis encoder having a 1/2 code rate for generating a 2-bit output signal based on a 1-bit input signal and generating 4 types of signal levels in baseband by using the 2-bit output signal for converting the 4 types of the signal levels of the trellis encoder to symbols and generating 4 types of output symbols. The present invention can improve the receiving performance of the VSB transmission system in a mobile environment by implementing the trellis coded modulation having 1/2 code rate in the VSB broadcasting transmission system, which critically decreases minimum signal-to-noise ratio for recovering an original signal.