Grass Valley SMS-6000 Series - Manual (Page 109)

5-5
Alignment
Analog Video Matrix
Equipment
2 channel 100MHz oscilloscope
TV vectorscope
TV waveform generator with the following:
■ Line rate monochrome signal such as grey scale or window,
■
Sweep (to 40MHz) or multi-burst (to 10MHz)
■
Color bars
Module Extenders (optional equipment)
75
Ω
cable, T-pieces, barrel and terminations
Only two parameters are adjusted for each output channel of the router.
These are insertion gain and high frequency response.
Insertion Gain
This method uses a two channel oscilloscope to subtract the input signal to
the matrix from the output signal of the matrix which shows a flat trace if
the insertion gain is correct. This avoids the use of very sophisticated
equipment and yet is very accurate.
1. Connect a cable from the output of the test signal generator, via a
T-piece through Channel 1 of the oscilloscope, into Input 1 of the
matrix. Connect a second cable from Output 1 of the matrix to Channel
2 of the oscilloscope terminating it at the oscilloscope in 75
Ω
.
2. Set the test signal generator to give a 1V p-p monochrome composite
waveform of a simple signal, such as grey scale or window. Set the
matrix so that Input 1 is routed to all outputs. Observe the two
waveforms on the oscilloscope. When these are satisfactory, disconnect
the leads to the matrix and join them together with a 75
Ω
barrel or T-
piece connector. Set the vertical amplifiers of the oscilloscope so that
the waveforms fill the screen as far as possible. Set the oscilloscope to
invert one trace and add it to the other. This should result in a flat trace.
If not, adjust one or other vertical gain slightly to optimize the flatness
of the waveform.