Commander
Reference
Lowpass
Filter
Type
Choose
the
type
of
lowpass
filter
you
want
to
apply
to
the
Scaled
Output,
for
each
channel
in
each
amplifier
mode.
The
options
are
Bessel
or
Butterworth.
Bessel
filters
are
preferred
to
Butterworth
filters
for
time
‐
domain
analysis.
Butterworth
filters
provide
lower
noise
than
Bessel
filters,
but
they
add
considerable
overshoot
and
are
best
used
for
frequency
‐
domain
analysis
(
i.e.,
noise
analysis).
The
selected
filter
type
is
displayed
in
the
Scaled
Output
tabs
of
the
Axoclamp
900A
Commander,
at
the
bottom.
Set
the
filter
cutoff
frequency
in
the
adjustable
field
to
the
right
of
the
filter
type.
See
also
Scaled
Output—Lowpass
Filter
.
Sync
Output
The
SYNC
OUTPUT
BNC
on
the
rear
panel
of
the
Axoclamp
900A
outputs
a
TTL
signal
(HIGH,
2–5
V;
LOW,
0–0.8
V)
synchronized
with
the
feature
selected
in
this
section.
This
can
be
used
to
send
triggers
to
an
oscilloscope,
data
acquisition
software,
or
other
equipment.
You
can
choose
to
follow
internal
commands
or
amplifier
mode
on
either
channel
exclusively,
or
on
the
channel
that
is
currently
selected.
A
channel
is
selected
when
one
of
its
Mode
tabs
is
uppermost
on
the
main
Commander
interface.
Tuning
or
Seal
Test
For
the
Seal
Test
and
Tuning
the
TTL
output
follows
the
seal
test
or
tuning
pulse,
going
HIGH
at
the
greater
voltage
or
current
phase
of
the
pulse
cycle,
and
LOW
at
the
lesser
phase.
A
HIGH
output
is
also
generated
for
the
duration
of
Pulse
and
Clear
commands.
There
is
no
TTL
output
synchronized
with
Buzz.
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