Grass Valley SMS-6000 Series - Manual (Page 48)

2-3
Electrical Connections
Electrical Connections
Refer toFigure 2-1 through Figure 2-6 on page 12 and page 13 for the rear
view of the frames when making the electrical connections to each frame.
Video Inputs and Outputs
These connections are made using standard 75
Ω
video coaxial cable. A
high quality cable such as Belden 8281, PSF1/2 or PSF1/3 or equivalents
should be used for optimum performance. It is both important and good
practice that cables are properly supported and not hanging on the
connectors as this can put unnecessary stress on the connectors and
possibly reduce their working life.
The video inputs are terminated in 75
Ω
within the equipment. The video
outputs are single 75
Ω
outputs.
Video Reference
The Ref input is a looping input. Any video signal with standard syncs may
be used as a reference signal to determine when crosspoints are switched
during vertical (picture) blanking. While a burst is not required the use of
color black is the most commonly available signal and is preferred. This
can be looped through into a video input of the unit.
Mixed sync pulses of 2V amplitude may also be used. 4V pulses can be
used but a modification is required to the main video router module and
involves the addition of a single 4.7K 5% resistor, labeled R126.
If no reference signal is connected then the unit will switch at random
intervals at a rate of about 40Hz.
NOTE: If one of the looping input connectors is not used then a 75
Ω
terminator
plug must be fitted on the unused connector, otherwise the level on the line will be
twice that expected and may cause incorrect operation of equipment attached to
this line.