Selecting
an
Individual Line
NOTE
For
field and line identification
systems,
refer to
Identifying Fields,
Frames,
& Lines in 525/60 and
625/50
TV
Systems
at
the end
of
this section.
The Sync Separator
circuit
does
not
differentiate
be·
tween the
two
fields
of
an
interlaced frame or among the
four
fields
of
the
PAL
color frame
sequence.
However,
if
a
1%
or
3%
field basic A
Sweep
cycle
is
used,
the
sweep
will
remain stably locked
to
a given display
until
the signal
is
interrupted.
ONE FRAME CYCLE.
To
display
an
entire vertical
blanking interval and locate a specific line
(e.g.,
one
of
the
lines containing a specific
VIT
waveform),
set
the A
TIME/
D
IV
switch
to
2
ms
and
the 8
TIME/DIV
switch (pull
to
unlock
from
A)
to
10
p.s.
Use
the Horizontal POSITION
control
to
center the second vertical blanking interval
to
center-screen
and
depress
the
10X
MAG pushbutton. This
will
provide sufficient resolution
to
identify
the field.
Adjust the A TRIGGER
HOLDOFF
as
necessary.
If
the displayed field
is
not
the desired one,
first
rotate
the A TRIGGER SLOPE control momentarily
to
the
opposite
polarity
then rotate back
again
until
the start
of
the desired field
is
displayed.
Press
A
INTEN
and
use
the
DELAY
TIME
POSITION
control
to
position the intensified zone
(8
Sweep) on the
desired line.
Pressing
the 8
DLY'D
button
will
then display
the desired line. Select
AL
T Horizontal Display
if
you wish
to
view the A
INTEN
trace
and
8
DL
Y'D
trace
simultaneously.
TWO
FRAME
CYCLE.
If
PAL
burst blanking
is
to
be
checked,
an
A
Sweep
3%-field cycle (5 ms/div,
with
the A
TRIGGER
HOLDOFF
at about
four
o'clock)
is
required,
using 8
Sweep
(AL
T mode recommended)
to
identify
fields
and
lines.
At
5 ms/div, only
two
and
a fraction fields
will
be
displayed
with
a
full
field covered
by
the trigger
holdoff
interval.
To
put
a specific field on-screen in a
particular location
will
typically
require
several
operations
of
the A TRIGGER SLOPE switch.
104
465B/DM44
Operators
@
I
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