this ppt will gives u the information of graphic terminal raster & random scan display principles

1. CAD/CAM
TOPIC: GRAPHIC TERMINAL (RASTER &
RANDOM SCAN)
By
J KUMAR CHANDRA,
ASST. PROF.,
DEPARTMENT OF ME,
NNRG-HYDERABAD

2. https://www.youtube.com/watch
?v=6BgcrRjqnKE
Working animation of CRT Monitor

3. Types of CRT display principles
1. RASTAR SCAN DISPLAY
2. RANDOM SCAN DISPLAY

4. CRT Display Principles
Electron beam swept across screen one row at a time from top to bottomin
raster-scan.

5. CRT Display Principles
Sample of Random-Scan displays principles.
Beam-penetration is used.

6. • Phosphor Persistence (PP)
- the light output decays exponentially with time.
- a phosphor’s persistence is defined as the time from the removal of
excitation to the moment of decaying the light to one-tenth of its
original intensity
• Refresh rate (RR)
- number of times per second the image is redrawn.
• Resolution
- the maximum number of points that can be displayed without overlapon
a CRT
- high-definition system, e.g. 1280 * 1024 pixels
- resolution depends on the type of phosphor, the intensity to be
displayed, focusing and deflection systems, size of videomemory
Properties of the CRT

7. Pros of CRT
The cathode rayed tube can easily increase the monitor’s brightnessby
reflecting the light.
They produce more colours
The Cathode Ray Tube monitors have lower price rate than theLCD
display or Plasma display.
The quality of the image displayed on a Cathode Ray Tube is superiorto
the LCD and Plasma monitors.
The contrast features of the cathode ray tube monitor areconsidered
highly excellent.

8. Cons of CRT
They have a big back and take up space on desk.
The electromagnetic fields emitted by CRT monitors constitute a health
hazard to the functioning of living cells.
CRTs emit a small amount of X-ray band radiation which can result in a
health hazard.
Constant refreshing of CRT monitors can result in headache.
CRTs operate at very high voltage which can overheat system or result in an
implosion.
Within a CRT a strong vacuum exists in it and can also result in a implosion
They are heavy to pick up and carry around

9. NEXT CLASS
CAD SOFTWARE DEFINITION AND
USES