Theory of Operation
WFM6100, WFM7000, and WFM7100 With Option FP Service Manual
2- 7
The hardware to support these features is contained on the EYE/PHY board,
which is installed in the center module slot. The Mezzanine board is removed
when Option EYE/PHY is installed, so the SDI connectors move from the back
panel lower right quadrant to the center. See the EYE/PHY block diagram on
page 2--8. The Audio blocks are not shown in this block diagram but, if
installed, still connect as shown in the Main Block diagram, Figure 2--1 on
page 2--2.
The selected SDI input signal is sampled by a wideband track-and-hold circuit,
and then digitized. The same signal is also applied to a cable equalizer and clock
recovery circuit. The recovered clock is divided by 10 for SD (by 20 for HD),
filtered to form a sine wave, and then digitized. Both the SDI input and the
recovered clock sine wave are sampled by the same asynchronous clock, and
then both are passed to the main board for processing by FPGAs. These arrays
produce the Eye Display, Jitter Display, Jitter Readout, and Jitter Thermometer.
The Eye Display data is further processed to derive the Eye Amplitude, Eye Rise
Time, and Eye Fall Time measurements, which are shown in the SDI Status
Display.
The selected SDI input signal also drives the Cable Meter circuit, which
measures signal energy at two frequencies. These measurements are read by the
CPU on the Main board, which calculates Cable Loss, Approximate Cable
Length, and Source Level for display in the SDI Status screen.
Fan Control
There are multiple temperature sensors in different locations in the instrument,
including some mounted on the Option boards. The control processor reads the
temperature sensors and sets a target speed for the fan. The fan circuit holds the
fan speed at the target by measuring the fan tachometer output, allowing reliable
operation at low speed. If the fan is not turning, the circuit senses the stall and
turns on a red LED (DS861 on the Main board). The fan is tested at power up. If
it fails, a message is shown on screen and also entered into the diagnostic log.
Power Supply and Distribution
The power supply has a universal AC input, enabling it to accommodate 100 to
264 VAC without any user range switching. The output is 5 VDC. Circuits
convert this output to any other supply voltage that they require at the point of
usage.
Fuses on the Primary supply 5 V output protect the main board.
The secondary supplies and their tolerances are specified in the troubleshooting
section. The location of the supply test points is shown in
Maintenance
section.
Operation
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Страница 12: ...Service Safety Summary viii WFM6100 WFM7000 and WFM7100 With Option FP Service Manual ...
Страница 64: ...Repackaging Instructions 4 34 WFM6100 WFM7000 and WFM7100 With Option FP Service Manual ...
Страница 76: ...Replaceable Parts 5 12 WFM6100 WFM7000 and WFM7100 With Option FP Service Manual ...