my ps2 is hooked up to a samsung digital reciever via optical cable. when playing games, the linear pcm light appears on the receiver and the pro logic 2 light does not appear. when the connection is through rca cables, the pro logic 2 light appears and the signal is no longer linear pcm. isnt an optical cable supposed to provide digital sound and the best quality? if so, why is the signal being recieved as linear pcm?