Tektronix WVR4000, Руководство по обслуживанию

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Theory of Operation
SDI I/O Board
Serial Digital Input
Processing
The serial digital inputs are AC coupled and buffered passive loopthroughs.
The signal passes through an ampli
fi er while traveling to the channel selection
switch. Only the ampli fi er corresponding to the selected channel is “on” (meaning
that only the selected amp gets DC power). The selected signal passes through
an equalizer whose digital differential pair output is sent over the ribbon cable
to the Main board.
AES Audio Input
Processing
The AES digital audio input is AC coupled and bit sliced by a comparator, the
single ended digital output of which is sent over the ribbon cable to the Main
board.
Reference I/O Board
Reference Input The Reference input is an AC coupled and buffered passive loopthrough. The
reference signal is applied to a sync separator, the single ended digital output of
which is sent over the ribbon cable to the Main board.
LTC Input The LTC input is a differential pair that is bit sliced by a comparator, the single
ended digital output of which is sent over the ribbon cable to the Main board.
Ground Closure Interface
Signals
The ground closure interface (GCI) signals are heavily fi ltered and protected
against adverse customer connections. Inputs (except Future 3 and 4) are buffered
and the digital outputs are sent over the ribbon cable to the Main board. Future
3 and 4, since they have no directional circuitry, could be used as outputs in the
future.
DVI I/O Board
DVI Output The DVI output is known as DVI-I, which means that it has both an analog output
(XGA) and a digital output (DVI). Both outputs are available simultaneously. A
failure of one output does not necessarily interfere with the other, nor does one
working output guarantee that both work.
Monitor Resolution The digital side of DVI is designed to auto-negotiate the best display resolution
possible with the monitor (once it senses that one is connected). However, the
instrument outputs are
fi xed XGA format, so if the monitor cannot support it, then
it is not going to work. Therefore, be certain your monitor works with a known
good WVR4000 or WVR5000 before suspecting a failure on the DVI board.
WVR4000 and WVR5000 Service Manual 5