Measure blood flow in vessels as small as 0.8 mm Monitor up to 6 vessels simultaneously Determine blood flow velocity through extracorporeal
cannulae Measure blood flow in vessels as small as 0.8 mm Monitor up to 6 vessels simultaneously Determine blood flow velocity through extracorporeal
cannulae 
The CBI 300-202 Pulsed Doppler Flowmeter module is a precision
instrument
designed to measure blood flow velocity in experimental preparations. As a
member
of the CBI System Modular Physiological Instrumentation family, it
operates
individually or in conjunction with other instruments when housed in a CBI
System
Chassis. The Pulsed Doppler Flow Module is a state-of-the-art system for
measuring
blood flow velocity. The low-mass, inexpensive transducers are ideal for long
term,
chronic implantation, particularly in small animals as compared to the bulky, heavy
transducers required for other technologies. These transducers use lightweight,
non-shielded bio-compatible PVC-insulated wire.
Blood flow velocity is measured by projecting bursts of high frequency ultrasound
diagonally across the blood vessel. Sound is backscattered from blood cells and the
frequency of the scattered sound is shifted in proportion to the velocity of the
cells.
The scattered signal is detected and a voltage proportional to the velocity of the
blood
flow is developed for recording. A variable range gate control allows the user
to measure
blood flow velocity at many points across a blood vessel.
This module incorporates a number of unique features not found in other designs: A
patented noise reduction circuit, Dynamic Noise Reduction, improves the
signal-to-noise ratio by as much as 10 dB compared to other pulsed Doppler
flowmeter
designs. The sampling Range is controlled by a front panel knob and
a DC voltage
proportional to the range is available at the back panel.
The most unique feature of the Model 300-202 is its internal calibration circuitry
which is not available on the other CBI type Doppler flowmeters. . Triton's calibration
is
a true end-to-end calibration using a group of frequencies developed from
the main
quartz crystal clock. These stable, accurate frequencies are determined from the
Doppler
equation, the operating frequency and the transducer geometry. Other commercial
pulsed Doppler designs utilize a simple
voltage divider across the power supply as a
calibration.
The pulsed Doppler Flow Module is available in 20 and 10 MHz versions for use on small
and medium blood vessels. Many
different implantable transducers
are available to suit specific applications.
DNR is a registered trademark of National Semiconductor
Copyright 1995 Triton Technology, Inc.
Updated March 28, 2006
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