Tektronix 2247A

Ess
Controls, Connectors, and Indicators
3
bas
the
A
Trigger
source
signal
amplitude
is
too low
or
the
frequency
is
less
than
10
Hz
or
the
Trigger
LEVEL
Is
not
appropriate.
The
triggering
level
changes
only
when
the
Trigger
LEVEL
control
is
adjusted
to
a
new
level
setting.
NORM-—Triggers
the
A
sweep
when
the
A
Trigger
LEVEL
control
is
i
set
within
the
peak-to-peak
limits
of
an
adequate
trigger
signal.
When
he
the
A
sweep
Is
not
triggered,
no
baseline
trace
is
displayed.
TV
LINE—Starts
the
A
sweep
at
the
beginning
of
a
video
signal
line.
{
SLOPE
polarity
must
match
the
composite
syne
polarity
to
obtain
TV
LINE
triggering
on
the
horizontal
sync
pulse.
TV
FIELD—Starts
the
A
sweep
at
the
beginning
of
a
video
signal
field.
SLOPE
polarity
must
match
the
composite
sync
polarity
to
obtain
TV
FIELD
triggering.
SGL
SEQ
(Single
Sequence)—Sets
up
the
A
sweep
for
single-
sequence
operation.
Each
additional
press
of
the
down-arrow
MODE
button,
when
In
single-sequence
mode,
resets
the
sweep
and
makes
It
ready
to
accept
a
trigger.
As
in
NORM
trigger
MODE,
the
set
trig-
gering
level
changes
only
when
the
TRIGGER
LEVEL
control
is
adjusted
to
a
new
level
setting.
When
triggered,
the
sweep
runs
to
produce
a
single
sweep
of
each
trace
as
required
by
the
setting
of
the
Vertical
MODE
and
Horizontal
~
MODE
switches.
Each
displayed
sweep
in
the
sequence
requires
a
distinct
A
sweep
triggering
event.
The
READY
light
remains
on
until
the
final
trace
In
the
sequence
Is
completed.
The
readout
and
cursors
can
be
set
to
turn
on
briefly
at
the
end
of
the
sequence
when
using
a
-
camera
(factory
settings
default
mode),
or
they
can
be
set
to
remain
on
by
changing
the
instrument
configuration
from
the
CONFIGURE
menu
(see
“Service
Menu
Features”
In
Section
3).
B Trigger Modes
AUTO
LEVEL—Sets
the
range
of
the
Trigger
LEVEL
control
to
the
10%
and
90%
levels
of
the
8
Trigger
source
signal,
sets
the
Trigger
LEVEL,
and
triggers
the
B
sweep
and
C/T.
2247A Operators