IOS exam - Optical discs
Test Your Knowledge on Optical Discs
Are you ready to dive deep into the world of optical discs? This quiz will challenge your understanding of various aspects related to CDs, DVDs, and Blu-ray technology. From data recording methods to playback formats, test your expertise!
- 12 engaging questions
- Multiple choice format with checkboxes
- Perfect for students and tech enthusiasts
At CDs:
- Bits are modulated in order to avoid very short runs of consecutive bits of 0, which have as result a high frequency of the signal generated at reading.
- One bit of 1 is represented by a pit and one bit of 0 by a land.
- Between two bits of 1 it can be recorded a run of bits of 0 of any length.
Which of the following methods is used to record data bits on CDs:
- A bit of 1 is recorded as a pit-to-land or land-to-pit transition, and a bit of 0 as no transition
- A bit of 1 is recorded as a land-to-pit transition, and a bit of 0 as a pit-to-land transition.
- A bit of 1 is recorded as a pit, and a bit of 0 as a land.
CD-R (CD Recordable):
- Contain a spiral groove that allows control of spin/rotation speed.
Contain sector addresses which are used by the unit for determining the current position on the disc.
- Uses an organic material with phase changing for the recording layer.
With a rewritable compact discs (CD-RW):
- Writing is performed with the highest laser power setting.
Rewriting is executed with the 2 settings of the laser for writing and deleting.
- Erasing is performed by heating the recording layer until it turns to an amorphous state.
- Erasing is executed by warming the layer over the crystallization point and quickly cooling this layer to maintain the state of the crystallization.
- An organic dye is used as a recording layer.
- A phase-change material is used for the recording layer.
The higher capacity of DVD discs compared to CDs has been obtained by:
- Using a more efficient modulation method.
- Reducing the wavelength of the laser beam.
- Reducing pit dimension (cavity dimensions).
- Reducing the numerical aperture AN.
Method for recording with constant angular velocity (CAV) used at different formats of DVD discs:
- Allows reducing energy/power consumption.
- Ensures a constant spin speed.
- Favors applications that need sequential access.
The constant linear velocity (CLV) recording method used for several DVD formats:
- Reduces the power consumption compared to the constant angular velocity (CAV) method.
- Ensures a constant rotational speed.
- Is advantageous for applications that require sequential access.
DVD+R Disks:
- Use an error management system that is more robust than that of DVD-R discs.
- Use a spiral groove with higher frequency of the sinusoid than that of DVD-R discs.
- Compared to DVD-R discs, they improve the linking accuracy between consecutive writing sessions.
- Stores addressing information by engraving pits in the area between the grooves.
At Blu-ray discs:
- Laser beam wavelength is reduced compared to the one of the DVDs.
- Numerical aperture of the objective lens is reduced compared to that of the DVDs.
- The coating layer thickness is reduced in order to compensate for the focalization of laser beam error.
BD-ROM AV format:
- Uses a transport stream that contains video and audio information and multiplexed graphics.
- Defined BD-Java mode, which allows interactive applications development.
- Defines HDMV mode, having a plan of presentation graphics/interface which allows displaying graphical menus.
BD-R and BD-RE Discs:
- Allows sinusoidal deviation, using Minimum-Shift keying Modulation, which reverse some phases deviation.
- Uses a spiral groove which is modulated through sinusoidal deviation for global intake of synchronization information.
- Uses a spiral groove with sinusoidal deviation which are modulated using two methods for a higher fiability.
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