Tektronix 2247A

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Controls,
Connectors,
and
Indicators
displayed
waveform
frequency
Is
time
related
to
the ac
power-source
frequency.
CPLG
(Up-Arrow
and
Down-Arrow)
Buttons
and
Indl-
cators—Select
the
method
of
coupling
the
Input
trigger
signal
to
the
A
or
B
trigger
system
as
directed
by
the
A/B
SELECT
button.
Pressing
the
Up-/Down
Arrow
buttons
selects
the
trigger
coupling
as
shown
by
the
CPLG
lights.
OC—Couples
de
and
all
frequency
components
of
a
triggering
signal
to
the
trigger
circuitry.
DC
coupling
Is
useful
for
most
signals,
but
It
Is
especially
useful
for
providing
a
stable
display
of
low-frequency
or
low-repetition-rate
signals.
NOISE
REJ
(Noise
Reject)—Couples
all
frequency
components
of
the
Input
signal
to
the
trigger
circuitry
but
increases
the
peak-to-peak
signal
amplitude
required
to
produce
a
trigger
event.
NOISE
REJ
coupling
Is
useful
for
improving
stability
when
the
trigger
signal
Is
accompanied
by
low-level
noise.
HF
REJ
(High
Frequency
Reject)—Attenuates
high-frequency
triggering
signal
components
above
50
kHz.
HF
REJ
coupling
Is
useful
for
providing
a
stable
display
of
low-
frequency
components
of
complex
waveforms
and
eliminates
high-
frequency
Interference
from
the
trigger
signal.
LF
REJ
(Low
Frequency
Reject)—Attenuates
low-frequency
trig-
gering
signal
components
below
100
kHz
and
blocks
the
dc
component
of
the
trigger
signal.
'
LF
REJ
coupling
Is
useful
for
producing
stable
triggering
on
the
high-
frequency
components
of
complex
waveforms
and
rejecting
low-
frequency
Interference
or
power
supply
hum
from
the
trigger
signal.
AC—Attenuates
trigger
signal
frequency
components
below
50
Hz
and
blocks
the
dc
component
of
the
signal.
AC
coupling
is
useful
for
triggering
on ac
waveforms
that
have
a
large
de
offset.
2247A
Operators
2-19