Patent ID: 7804918

Claim:
An apparatus for independently extracting streams from a hierarchically-modulated signal and performing a soft-decision, comprising: a synchronizing means for receiving the hierarchically-modulated signal configured of an I-channel signal and a Q-channel signal from an external device and performing a synchronizing process on the received signal; a divaricating unit for divaricating the synchronized signal configured of the I-channel signal and the Q-channel signal from the synchronizing means; a high priority (HP) stream extracting and soft-decision means for extracting a HP stream from one of the divaricated signals, and performing a first soft-decision; a processing means for processing the other of the divaricated signals to allow constellation points to be distinguished; and a low priority (LP) stream extracting and soft-decision means for extracting a LP stream from the processed signal from the processing means and performing a second soft-decision; wherein the processing means comprising: an absolute value calculating unit for obtaining absolute values of the I-channel signal and the Q-channel signal in the other of the divaricated signals; a trigonometric function generating unit for generating a sine value and a cosine value; a multiplying unit for multiplying the two absolute values from the absolute value calculating unit with the cosine value and the sine value from the trigonometric function generating unit in a one to one manner; and an adder for adding the I-channel signal and the Q-channel signal which are multiplied with the cosine value and the sine value from the multiplying unit and transferring the adding result to the LP stream extracting and soft-decision means.