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Reference
3–52
WFM 601A, WFM 601E & WFM 601M User Manual
Comparison of the Two Methods. Of the two methods described above, the EDH
system is the most powerful. First, it works with any video program material,
since the source-end CRC is calculated on a field-by-field basis. It does not
matter if the source is a fixed pattern test signal or moving pictures. Thus, EDH
can monitor error rate while your facility is in service. Second, the error
information gathered by the waveform monitor is the most comprehensive when
using EDH, with errored seconds readouts for both the active picture and full
field. The big disadvantage of EDH is that it requires calculation and insertion of
the CRC at the source. At present, not many equipment vendors support EDH.
The AP CRC Value method does not require any special signal insertion at the
source, and therefore gets around the problem of poor support for the EDH
system. But its limitation is that it works only with fixed pattern signals, such as
those from a test signal generator. This precludes its use for monitoring operating
video systems. Also, the AP CRC Value method only indicates if there were zero
or more errors.
Sweep
The SWEEP buttons set the sweep rate (time/div) for the horizontal scale and
enable horizontal magnification. Press the LINE/FIELD button repeatedly to step
through the following sweep modes:
H 1 Line. One horizontal line is displayed. Use Line Select function to choose
one line out or a Field or Frame. The horizontal scale is 5 ms/div.
H 2 Line. Two consecutive horizontal lines are displayed. The horizontal scale
is 10 ms/div.
H 1 Field. All lines for one video field are displayed. No horizontal scaling is
given.
H 2 Field. All lines for two video fields are displayed. No horizontal scaling is
given.
Use the LIN SEL MENU to choose the line or lines to display.
The MAG button provides a magnified view of the horizontal scale. In the
magnified mode, the waveform extends off both sides of the CRT. Use the
HORIZ POS bezel knob to pan left and right on the waveform. Timing Cursors
operate correctly in the magnified mode, though one or both may be off screen
during measurement.