The Leader LT4446 Changeover Unit for LT4600 Signal Generator switches the LT4600 to the backup signal if detecting problems on the primary signal, problems such as errors in amplitude. It supports two systems of input signals at a time and provides 11 channels. The channels of the LT-4446 support SDI, analog black burst, tri-level sync, AES/EBU digital audio, and word-clock signals, depending on the configuration of the internal switches of the changeover.