Study Notes
Data representation involves converting text, sound, and images into a format that computers can process. Character Sets — A collection of characters each assigned a unique code. Example: ASCII uses 7-bit codes for 128 characters. Extended ASCII — An 8-bit character set allowing for 256 characters. Example: Includes additional symbols beyond standard ASCII. Unicode — A character set that uses 16 or 32 bits to represent a vast number of characters. Example: Supports modern emojis. Sound Representation — Digital storage of sound wave properties like amplitude and frequency. Example: ADC converts analog sound to digital form. Sampling Rate — The number of samples taken per second in digital audio. Example: 44.1kHz is standard for CDs. Bitmap Images — Images made up of pixels stored in a 2D matrix. Example: Color depth determines the number of colors a pixel can display.
Exam Tips
Key Definitions to Remember
- Character Sets: A collection of characters each assigned a unique code.
- ASCII: A 7-bit character set with 128 characters.
- Unicode: A character set using 16 or 32 bits for a wide range of characters.
- Sampling Rate: The number of samples taken per second in digital audio.
- Bitmap Images: Images made up of pixels stored in a 2D matrix.
Common Confusions
- Confusing ASCII with Unicode in terms of character range.
- Mixing up sampling rate and sampling resolution.
Typical Exam Questions
- What is ASCII? ASCII is a 7-bit character set with 128 characters.
- How does sampling rate affect audio quality? Higher sampling rates provide better audio quality by closely resembling the original sound.
- What determines the color depth of an image? The number of bits allocated to each pixel.
What Examiners Usually Test
- Understanding of different character sets and their uses.
- The process of converting analog sound to digital.
- How bitmap images are represented and the impact of color depth.