Grass Valley SMS-6000 Series - Manual (Page 20)

1-3
The Frame
Signal Path
The signal path has been designed to be as short as possible which reduces
the variations in path length between channels and maintains the overall
transparency through the router so important in broadcast applications
where multiple passes through equipment are required.
Inputs
The video inputs are terminated in 75
Ω
.
The main video module contains input buffers which have a high input
impedance to aid the return loss performance and an output capable of
driving the bank of crosspoint switches. The buffers can operate in two
modes: DC restored for use with composite signals or component signals
with sync present.
Alternatively the buffers can be set to operate in a DC coupled mode for
use with RGB or color difference signals which have no sync component.
The mode is selected by the user for each input by jumper links on the main
plug-in video module. This means that a single video matrix can handle a
mixture of composite and component inputs.
The DC restorer is a feedback sync tip restorer which prevents any
crushing of the sync signal.
Crosspoints
The video crosspoint matrix consists of an array of 16x1 surface mount
assemblies. Sixteen of these assemblies are required to provide a matrix of
16x16 on each matrix module.
Outputs
The video modules have output amplifiers built on thick film hybrid
circuits. They incorporate adjustment controls for gain and high frequency
response which are factory set.