ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...
Circuit breaker
1. CIRCUIT BREAKER
Prepared by: Mabel Espinosa
ELXT 2101
Submitted to: Mr. Oscar B. Barte
Instructor I – ELXT 211
Industrial Electrical Components, Control Devices, and
Test Instruments
3. HD TV
Prepared by: Mabel Espinosa
ELXT 2101
Submitted to: Mr. Oscar B. Barte
Instructor I – ELXT 211
Television Systems
4. HD TV Basics:
• Applications
• Operations
• Characteristics
A woman walks along the Matsushita's 150-inch
Advanced High-Definition Plasma Display.
5. Applications
• HDTV is a high-quality video standard developed to replace older
video formats often referred to as SDTV (standard definition
television).
• High-definition television (HDTV) provides a resolution that is
substantially higher than that of standard-definition television.
• It is a television display technology that provides picture quality
similar to 35 mm. movies with sound quality similar to that of
today's compact disc. Some television stations have begun
transmitting HDTV broadcasts to users on a limited number of
channels.
6. Operations
• HDTV generally uses digital rather than analog signal transmission.
• Standard TV broadcasts send the radio waves they consist of in an
analog fashion. They modulate the signal to provide changes that the
television can process into images.
• Digital signals use a changing pattern of 1's and 0's, just like computers.
The result is an image with much higher resolution, less fuzzy, fewer
sharp corners in parts of the picture and overall a better looking display
but in an HDTV The results are clearer pictures, sharper, more realistic
colors and a look that's much closer to the 35mm film resolution on
which most movies were originally shot.
• Most HDTV sets support 5.1 Dolby surround sound stereo.
• Different manufacturers offer different frame rates and techniques for
'painting' the screen.
7.
8. • A 'frame rate' is the number of times per second the gun moves
completely across the screen. Anywhere from 25 to 60 frames per
second.
• The 'painting' is done by moving the gun from top to bottom, in one
or two passes. When it is done in two passes, the gun skips every
other line, then comes back and does the skipped lines. That is
called interlacing whereas in 'progressive scan' systems all the lines
are illuminated in one pass.
• For example, 1080i50 is equivalent to 1920 x 1080 pixels, interlaced,
projecting 50 fields (25 frames) per second.
• The visual results of the different frame rates and of using 'i' vs 'p'
methods is often debated. In general a higher frame rate results in a
smoother looking image. Interlacing helps to reduce flicker under
certain conditions.
•
9. Characteristics
• Black Level
– Traditional LCD displays aren't very good at reproducing very dark
colors because there's always light behind every pixel. This can be mostly
eliminated by LED backlighting, although right now that's only available
on high end LCD HDTVs. DLP and plasma HDTVs don't generally have
any problems in this area.
• Brightness
– Just as a HDTV should produce dark blacks, it should also produce bright
whites. Even though LCDs are generally not as bright as DLP or plasma
HDTVs, they may seem brighter due to their high color saturation
• Contrast
– Due to the combination of factors that go into black level and brightness,
DLP HDTVs have varying contrast, largely determined by the quality of
their color wheel. This is where plasma excels due to its combination of
good black levels and brightness, generally resulting in the best contrast.
10. • Image Processing
– The picture displayed on a HDTV may be
processed in a number of ways before getting
being displayed. It can be sharpened, which can
make edges crisp but also create jagged lines in
place of smooth edges. Smoothing can reduce
jagged edges at the expense of a certain amount
of detail.
• Color Saturation
Just as with old fashioned analog TVs, color saturation in HDTVs varies widely
from model to model. As with other aspects of the picture, the display technology
can have an impact here as well. Plasma displays tend to have good, even
saturation, as do many high end LCDs.
11. • Screen Composition
– Screens made of different material obviously have different reflective
properties. Even a display that performs well in a well lit room can be affected
by glare, particularly from direct sunlight. The glass screens on plasma
displays are generally most prone to this problem. No display performs at its
peak with light shining directly on the screen, so this is mainly an issue in
rooms where you don't have much control over lighting conditions.
• Tuners and Cable Card
– Depending on how you'll be getting your HDTV broadcasts you may want to
consider a HDTV with multiple tuners or a CableCard interface. Multiple
tuners can be used to receive DVB-C cable television and DVB-T Over The Air
(OTA) signals on the same TV. In the U.S. a CableCard interface is used to
connect digital cable television directly to your TV (or DVR) without requiring
a set-top box.