Interphase Color Twinscope, Operation Manual

Page: 6 / 88

6
Principle of Operat
ion
The Twinscope Forward Scanning Sonar uses a proprietary
phased array acoustic technology first developed for marine
use by
Interphase Technologies . Known as “phased array
ultrasound technology”, its capabilities have been proven 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.
Present day fish finders/ depth sounders all work on a principle
developed during W.W. II, called SONAR, where acoustic
pulses are used to detect the presence and range or distance to
an underwater object. During the 1950’s, several devices
which used sonar principles were developed and marketed to
fishing and boating enthusiasts to detect the distance to the
bottom (depth) and to indicate the presence of any intervening
submerged objects - such as fish.
An acoustic array is a group of piezoelectric ceramic elements
that are precisely sized and spaced. Each element will send
and receive acoustic pulses, as when used in more
conventional single element depth sounders. However, when
all 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 ability of the
array to concentrate its acoustic energy in different directions,
depending on the different “phasing” of the signals applied or
received by each element. Depending on the signal phasing of
the array, acoustic beams can be directed in an almost
unlimited number of directions. For example, using a 16
element phased array transducer, the
Twinscope is capable of
steering the acoustic beam in any of 90 different directions in
either the horizontal or vertical direction. Conventional fixed-
beam technology would require the use of 180 different
elements to duplicate this capability. The resulting transducer
would be much too large and costly to be of any practical use.
Since the acoustic beam in the phased array is steered
electronically, requiring no moving parts, it can be quickly and
reliably scanned and re-scanned over a large area. When
displayed, the changing information between subsequent scans
takes on an almost animated quality - for example, showing
movement of underwater targets such as fish or rapidly
changing bottom conditions.
Award Winning
Technology
For its pioneering work in developing
Phased Array Scanning Sonar,
Interphase Technologies won the
prestigious IMTEC INNOVATION
AWARD .
The Twinscope Forward Looking
Scanning Sonar is based on this same
award-winning technology.