Interphase Twinscope Operation Manual page 74

sides of the underwater beam, the transducer will
receive echoes from both fish targets at the same
time and the display will only show a single target.
This is a serious limitation to the conventional
technology.
To get around this limitation, several manufacturers
have resorted to adding more piezoceramic elements
to the transducer, each pointed in a different
direction. By selectively using each piezoceramic
element the transducer has the ability to point or
look in as many different directions as there are
piezoceramic elements. After approximately four
elements, however, the transducer housing starts to
become physically large and cumbersome. To date,
manufacturers have put as many as five separate
elements into the transducer to enable users a view
in up to five different underwater directions. In the
future, Interphase believes that this multiple fixed-
beam approach has serious limitations, especially for
use in more advanced products where maximum
underwater coverage and resolution are important.
Development of New Technology
To get around these limitations and provide a sonar
system that can achieve both outstanding coverage
and good resolution, Interphase pioneered the use
of Ultrasonic Phased Array Technology. In 1991
we received the prestigious IMTEC Innovation
Award in recognition of the importance of this new
technology to the marine industry. Although new to
the sportsfishing and recreational marine industry,
"phased array ultrasound technology" has proven its
capabilities in the medical industry for many years.
The amazing video images provided by medical
ultrasound equipment are familiar to most people
and clearly demonstrate the technology's ability to
show highly defined images in a real-time or live-
action mode. Interphase has taken this same
technology and modified it for use in the marine
market.
An acoustic phased array is a group of piezoceramic
elements that are precisely sized and spaced. Each
element will send and receive acoustic pulses as
when used in the conventional single element
technology. However, when all the elements in the
array are sending or receiving acoustic energy at the
same time, the entire array behaves like a single
larger element with one important difference: the
Three Fixed-Beam System, Looking Down and
to Each Side of Boat
12º Acoustic Beam Can
Be Steered In Any
Direction Over a 90
Degree Arc.
8 Element
Ceramic
Phased
Array
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