UFi FETRODE 2283FT User manual

MODEL 2283FT/2283FTi
FETRODE™ AMPLIFIER
UFI
545 Main Street, Suite C-2
Morro Bay, CA 93442
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Introduction to Fetrode ™ artifact reduction
High impedance at the skin-electrode contact correlates
directly with the amplitude of the noise artifacts that can
plague bio-electric recordings. Historically, there have been
only two ways to reduce such noise: 1) use the very best
Ag/AgCl electrodes with a liquid-junction interface; and 2)
abrade the skin to reduce the skin/electrode contact
impedance. With the prevalence of HIV and hepatitis
viruses, breaking the skin barrier is no longer advisable.
Fetrodes™ eliminate the requirement to abrade the skin.
The Fetrode™ is a unique, temperature-compensated
amplifier with an extremely high input impedance and a
very low output impedance. The circuitry is built with state-
of-the-art surface mount technology into a miniature
enclosure that can be snapped onto any high-quality
electrode. This innovation places signal buffering directly on
the active electrode site. In so doing, the Fetrode™ virtually
eliminates artifacts due to electrostatic potentials and cable
noise, even with high electrode contact impedances.
The Model 2283FT is a stand-alone Fetrode™ bioamplifier
that meets many physiological research needs. Adjustable
gain and frequency response suit it to a wide variety of
input signals and downstream instruments. The Model
2283FTi Fetrode™ amplifier is just the same as the Model
2283FT, except that it incorporates subject isolation using
an off-the-shelf signal isolator.

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Controls and connectors
Power switch
•Connects power supply to Model 2283FT(i);
should be left in OFF position when instrument is
not in use.
Power meter
•Should read in the green zone when power switch
is in ON position.
Power connector (back panel)
•Connect supplied wall-mount transformer power
supply to this jack.
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Four-pin input connectors (back panel)
•Connect the two supplied Fetrode™ buffer
assemblies to these black receptacles, which are
located on the left side of the back panel.
Green ground reference connector (back panel)
•Plug the supplied ground reference lead into this
0.080” jack, located between the two four-pin
Fetrode™ connectors.
Amplification switch
•Use this four-position rotary switch to select the
amplification (gain) factor applied to the Fetrode™
buffer assembly outputs.
•Choices are
oX10
oX100
oX1000
oX10000

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Low frequency switch
•Use this three-position rotary switch to select the
low-frequency rolloff applied to the Fetrode™
buffer assembly outputs.
•Choices are
o0.02 Hz
o0.15 Hz
o1.50 Hz
CMR adjust
• Adjust this multi-turn potentiometer to minimize
common-mode interference (usually 50/60 Hz
power line noise) .
Output connector (back panel)
• Connect your recorder or other downstream
device to this BNC receptacle.
Electrode considerations
•Use only good quality Ag/AgCl electrodes, such as
UFI Model 1081SNP, that include snap fasteners
to which the Fetrode™ buffer assemblies can be
attached.
•Do not use inferior electrodes, for example those
with stainless steel inserts.
•Subject’s clothing, especially polyester materials,
will probably generate electrostatic noise if subject
moves. Fetrodes™ may pick up such noise.
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•Prevent electrostatic noise by asking your subject
to remove clothing or to wear tight-fitting clothing
that cannot move enough to generate noise.
•You must use ground (reference) electrode.
Locate it roughly equidistant from active electrode
sites (those equipped with Fetrode™ assemblies).
•Do not abrade active electrode sites. You may
need to abrade the ground electrode site if you are
recording low- frequency, low-level signals when a
large 50/60 Hz powerline noise source is present.
Using the Model 2283FT(i)
•Select appropriate electrode sites for desired
measurements.
•Apply electrodes to subject, then snap two
Fetrode™ buffer assemblies to electrodes.
•Snap ground reference lead to electrode and plug
other end into green jack on back panel.
•Connect Model 2283FT(i) output jack to your
recorder or other downstream device.
•Turn power switch to ON position.
•Rotate amplification switch until signal to recorder
is maximum size without clipping.
•Rotate low-frequency switch to roll off (suppress)
undesired low frequencies.
•If signal is upside down, just unsnap leads to
Fetrodes™ and reverse connections.
•Adjust CMR control for minimum 50/60Hz
interference.

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Model 2283FT specifications
•Input impedance 100 megohms
•Fetrode™ input receptacles 2 Switchcraft TB4M;
fit TA4F plugs
•Frequency response 0.01 - 1200 Hz +/- 3 dB
•Common mode rejection 70 dB minimum
•Noise Less than 3 µV peak-
to-peak, referred to
input
•Output configuration Single-ended BNC
•Output impedance Less than 15 Kohms
•Power supply 110 VAC-to-12 VDC
wall-mount transformer
•Case size 6.8"W x 2.5"H x 4.8"D
(17.1 x 6.4 x12.1 cm)
•Weight 16 ounces (450g)
Model 2283FTi additional specification
•Minimum isolation voltage 2000 volts
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Warranty and repair
All UFI instruments are warranted against defects in
materials and workmanship to the original purchaser for a
period of one year from the date of original purchase. This
warranty is void if our inspection shows the equipment has
been tampered with; or installed at variance with factory-
designated procedures; or has been subjected to
negligence, misuse, or accident beyond normal usage; or
has had the serial number altered, defaced, or removed.
All questions regarding the warranty should be directed to:
Customer Service Department
UFI
545 Main Street, Suite C-2
Morro Bay, CA 93442
Email: [email protected]
No third party, including any dealer or agent, is authorized
to assume any liability for UFI.
When corresponding or communicating with UFI
concerning your equipment, please include the model and
serial numbers.
10-18-10