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Pulse Transducers
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Updated: 12.3.2012
PULSE PHOTOPLETHYSMOGRAM TRANSDUCERS
TSD200 for MP150/MP100 System
SS4LA for MP3X and MP45 System
The TSD200/SS4LA consist of a matched infrared emitter and
photo diode, which transmits changes in blood density (caused by
varying blood pressure) in specific body locations. When the
TSD200 is attached to the skin, the infrared light is modulated by
blood pulsing through the tissue below. The modulated, reflected
light results in small changes in the resistance of the photo resistor,
which yields a proportional change in voltage output.
The TSD200/SS4LA includes a shielded 2-meter cable and a stretchable Velcro
®
strap for easy attachment to the
fingers, or it can be taped to other body parts. The TSD200/SS4LA can also be placed on other body locations by
employing ADD208 adhesive disks to hold the transducer in place. Use the TSD200C ear clip transducer for easy
attachment to the ear.
Place the transducer around the finger and adjust the Velcro
®
closure to provide only slight tension. Blood
density readings can vary considerably depending on transducer location and tension changes.
The TSD200 connects to the PPG100C as follows (See also: PPG100C for a diagram):
TSD200 Lead
PPG100C
Red
lead
+VSUP
Black
lead
GND
Purple or Blue lead
INPUT
The SS4LA plugs directly into the MP3x or MP45.
CALIBRATION
The TSD200/SS4LA does not require calibration.
TSD200C PHOTOELECTRIC PULSE PLETHYSMOGRAPH WITH EARCLIP
The photodetector operates via incident photons, from an IR transmitter, impacting an IR detector. The incident
photons result in a proportional passage of electrons in the detector. The IR detector operates like a photon-
controlled current source. The transducer incorporates an appropriate clipping range, with linearity insured for
arbitrarily low levels of reflected light. For the expected magnitude of incident infrared light, the photodetector
operates in a linear fashion. Situations have not been encountered where the detector is operating non-linearly
(near saturation).
The TSD200C transducer operates with the
amplifier to record the pulse pressure waveform. The
TSD200C consists of a matched infrared emitter and photo diode, which transmits changes in infrared reflectance
resulting from varying blood flow. The ergonomic housing design improves contact with the subject and helps
reduce motion artifact. The TSD200C is primarily designed for ear attachment and comes with a shielded 3-meter
cable and ear clip.
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