Thanks for the reply. I've connected like this
STB(HDMI OUT(ARC) - HOME THEATRE(HDMI IN) and HOME THEATRE(HDMI OUT(ARC) - TV(HDMI IN)
I am still getting LPCM 2.0 48Khz. I've changed the Audio Settings in STB. "Preferred Audio through HDMI" was set as STEREO. I've changed it to Dolby Digital. When i make the change, all the channels Sound goes off and Hone theatre remote becomes inaccessible. Only When i set to Stereo it works.
I could see "Preferred Audio through Optical/SPDIF" set as Dolby Digital in STB. So before going for Optical Audio connection, want to ensure if it supports.