Additional slave channel for CO490 SPG changeover is a universal, modular automatic SPG changeover unit. It works in conjuntion with Sigma's full-featured TSG490 SPG and Test Pattern Generator but can be easily incorporated into any system currently containing an SPG or test pattern generator. It accomodates up to 12 channels where channel 1 is a measured channel, 2 - 6 can be additional measured channels and 7 - 12 can be either measured or slaves.