Atec Tektronix-VM700T - Manual (Page 12)

12
Measurement Methods —
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The following paragraphs
describe the measurement
methods for each measurement.
Each timing measurement
method is written for the FCC
method. If there is an RS-170A
method for that same measure-
ment, and the RS-170A method
differs from the FCC method, the
RS-170A requirement is
enclosed within square brackets
in the FCC description.
Horizontal Interval Timing
Measurements
These timing measurements are
made within the active picture
area, averaging the results over
32 lines starting at line 50 and
skipping 1-frame plus 5 lines for
each successive sample (i.e.,
average over line 50 of first field,
line 56 of second field, line 62 of
the third field, etc.).
Breezeway Width: Measured
from the 10% point on the
trailing edge of horizontal
sync (nominally –4-IRE) to the
leading half-amplitude point
of the burst envelope.
Color Burst Width: Measured
from the leading half-ampli-
tude point on the burst enve-
lope [leading zero crossing of
the first half-cycle of burst
that exceeds 50% of burst
amplitude] to the trailing half-
amplitude point on the burst
envelope [trailing zero cross-
ing of the last half-cycle of
burst that exceeds 50% of burst
amplitude].
Sync-to-Start-of-Burst:
Measured from the 50%
point on the leading edge
of sync (nominally –20 IRE)
to the leading zero crossing
of the first half-cycle of burst
that exceeds 50% of burst
amplitude.
Sync-to-End-of-Burst:
Measured from the 10%
point on the leading edge of
horizontal sync (nominally
–4 IRE) to the half-amplitude
point on the trailing edge of
the burst envelope.
Vertical Interval Timing
Equalizing Pulse Width:
Measured between the
10% [50%] points on the
equalizing pulse (nominally
–4 [–20] IRE).
Serration Width: Measured
between the 10% [50%]
points of serration (nominally
–4 [–20] IRE).
Vertical Blanking Width:
Measured between the points
on setup [active picture] at a
level equal to 10% [50%] of
sync amplitude (nominally
+4 [+20] IRE), where setup
[active picture] immediately
precedes and follows the
vertical blanking interval.
Front Porch Duration:
Measured from the 10% point
on the trailing edge of setup
(+4 IRE nominally) to the 10%
[50%] point on the leading
edge of sync (nominally –4
[20] IRE).
Horizontal Blanking Width:
Measured between the points
on the leading and trailing
edges of horizontal blanking
that are at an amplitude of
10% [50%] of sync above
blanking level (nominally +4
[+20] IRE).
Horizontal Sync Rise Time
and Fall Time: Measured
between the 10% and 90%
points on the leading and
trailing edges of horizontal
sync, respectively (nominally
–4 IRE and –36 IRE).
Horizontal Sync Width:
Measured between the
10% [50%] points on the
leading and trailing edges
of horizontal sync (nominally
–4 [–20] IRE).
SCH Phase: Phase at the
middle of burst relative to
the 50% point on the sync
leading edge.
Sync to Setup: Measured from
the 10% [50%] point on the
leading edge of sync (nominal-
ly –4 [–20] IRE) to the point
on the trailing edge of blank-
ing that is equivalent to 10%
of sync (nominally +4 IRE).