What is "zweikanalton"

Zweikanalton ("two channel sound") or A2 Stereo, is a television sound transmission system used in Germany, Austria, Switzerland, Netherlands and other countries that use or used PAL-B or PAL-G. South Korea formerly utilised its variant of this format in analogue television system until 31 December 2012. It relies on two separate FM carriers.

This offers a relatively high separation between the channels (compared to a subcarrier-based multiplexing system) and can thus be used for bilingual broadcasts as well as stereo. Unlike the competing NICAM standard, Zweikanalton is an analog system.