i wanna to convert my Analog TV signal to digital so that i can see TV channel in laptop..I want to design my own adapter rather than to buy so any suggestion related to diagram or design will be very helpful..Thanks in advance.
It sounds like you want to design and build a USB TV tuner for your laptop. Do they still broadcast in analog were you live? Most TV broadcasting is in digital. You still need a tuner for that.
You could google for TV tuner chips. https/www.silabs.com/products/tv-and-video/tv-tuners