Biomedical Engineering Reference
In-Depth Information
(a)
(b)
Pixel
Pixel
Gates
Sensor
Node and
Amplifier
(d)
(c)
Figure 6.2-3 (a)-(d) Internal look at a CCD array and the charge transport.
scene. The area fill factor can be as low as 20%. Since the
detector is only 20% of the pixel area, the output voltage
is only 20% of a detector, which would fill the pixel area.
A fraction of the light can leak into vertical registers
but this can be minimized by using shielded storage array.
There are several types of transfer register architectures.
In
Figure 6.2-8
we can observe a four-phase transfer
register that carries charge under two gates. The 2:1 in-
terlace has both fields collected at the same time but are
read out alternately.
major telecommunications company spends millions of
dollars developing and utilizing an optical fiber commu-
nications system. Fiber-optic communication systems
can process information using either digital or analog
modulation schemes. In the most commonly used fiber-
optic communication system, voice, video, and data are
converted to a coded pulse stream of light using a suitable
light source. This pulse stream is carried by optical fibers
to a regenerating or receiving station. At the final re-
ceiving station the light pulses are converted into the
form of the original information. Optical fiber com-
munication systems are currently used in the fields of
telecommunications, data communications, and cable
television. These systems are also used for many military,
automotive, medical, and industrial applications.
Since the dawn of history, people have used light as
a vehicle to carry information. Lanterns on ships and
smoke signals or flashing mirrors on land are early ex-
amples of how light was used to communicate. It was
6.2.2 Optical fiber
Communications using light as a signal carrier and optical
fibers as the media are termed
optical fiber communica-
tions.
The applications of optical fiber communications
have increased very rapidly since the first commercial
installation of a fiber-optic system in 1977. Today every
