Versatile change-over switch for unbalaced signals

The VCT2000C01 is an automated switch designed for use with analog video signals (PAL, NTSC, Black Burst, Tri-level Sync, etc.) as well as digital video signals (DVB-ASI or 3G/HD/SD-SDI) transmitted over coaxial cables. The VCT2000C01 can also be used with other signals that use coaxial cabling such as G.703 at 2 Mbit/s, 34 Mbit/s or 155 Mbit/s or 10 MHz (1 PPS) reference signals.
The VCT2000C01 provides two inputs labeled MAIN and RES and one output that puts out the selected input. The decision regarding which input to send to the output at any given time is made based upon the presence of signal at the two inputs. Alternatively, either of the two inputs can be selected regardless of signal presence by using the Manual and GPI modes of operation.
Detection of signal presence is performed via analysis of the period of the vertical sync for analog video, via the period of the pulses in the case of 1 PPS signals and based upon signal level for all other signal types.
The VCT2000C01 has four operating modes for selection between its two inputs. These are: Automatic Mode, Semiautomatic Mode, Manual Mode and GPI Mode. Any switching between inputs is indicated with an LED and an acoustic beep.
The VCT2000C01 module uses relays for signal switching and therefore does not perform any signal processing on the signals that it switches. The relays default to the Main input in case of a power supply failure.