How can I connect an Apple TV to an older television?
You're having a hard time determining it cause those "yellow / white" cables are called "RCA" ports, created by one of the first TV makers and ironically mostly sold off to Japanese companies.

Searching for "RCA to HDMI converter" yields a wealth of converters and opinions about the best devices based on the model of TV

such as this article:

http://techchannel.radioshack.com/convert-hdmi-rca-1778.html