Hdtv Smart Antenna Canada Is It Possible To Combine Broadcast HDTV And Analog Cable Signals Using A Diplexer?

Is it possible to combine broadcast HDTV and analog cable signals using a diplexer? - hdtv smart antenna canada

I have a Sony, which obviously new HDTV tuner, which accept regular or NTSC or Hi Def channels. But like most televisions, which has a coaxial RF. I do my basic cable service for analog and high-definition television (via satellite) on the TV cable. It can be done? And HDTV is smart enough to switch to a position between analog and digital channels in the same RF input? Example is the distignuish between TV broadcasting in HD from CBS and the regular version of himself?