Complex sentence: CFRE and its sister station in Saskatoon, CFSK, were branded as STV, it became part of the CanWest Global System in 1990 until the Global identity was extended to all of Canwest's stations in 1997.
Split into simpler sentences: CFRE and its sister station in Saskatoon, CFSK, were branded as STV. It became part of the CanWest Global System in 1990 until the Global identity was extended to all of Canwest's stations in 1997.