03 Analog and Digital Information W2024 K

Analog vs. Digital Information

• Scope: Understanding the differences between analog and digital information is crucial in electrical engineering and computer science.

• Importance: Key concepts and representations of information are fundamental for various applications in engineering.

Information, Data, and Signal

• Information: Refers to knowledge that is recorded or transmitted. Examples include:

  • A person's weight.

  • Current time.

  • An image of a cat.

• Data: Representation of information:

  • Weight examples: 63 kg, 139 lb, or 9 st 13.

  • Time examples: 13:34:16, 1:34:16 PM, etc.

  • Other representations like 'one average goat' or 'seven watermelons'.

• Signal: A means to record or transmit data or information such as:

  • Voltage or current.

  • Handwritten notes or markings.

Types of Information

• Inherently Continuous: Infinite values in any range:

  • Mass, temperature, body temperature, blood pressure, sound, images, video.

• Inherently Discrete: Finite values in any range:

  • Days of the week, number of steps walked, names of cities, text and symbols.

Analog vs. Digital Representation

• Analog Data: Continuous representation, resembles actual information representation.

• Digital Data: Represents information discretely using finite digits or symbols.

• Question raised: Can continuous information be represented using digital data?

Examples of Representation

• Analog Example: A spirit thermometer shows continuous change in liquid level corresponding to temperature.

• Digital Example: Digital devices display information in a discrete manner.

Precision and Accuracy

• Current Temperature Measurement:

  • Example: Thermometers show infinite precision but accuracy can vary based on manufacturing quality.

• Time Measurement Limitation: Digital representations may lose precision (e.g., seconds).

Measuring Techniques

• Various instruments are used for measuring continuous properties:

  • Mercury Sphygmomanometer: Highly accurate, uses toxic mercury.

  • Aneroid Sphygmomanometers: Less accurate, non-toxic.

  • Digital Sphygmomanometers: Fairly accurate and user-friendly.

Representation of Speed

• Different formats to represent speed, such as numeric displays on vehicles.

Questionnaire Examples

• Use of discrete scales to quantify reading habits or performance:

  • Examples of discrete values for easy analysis.

Computer Limitations

• Finite Nature of Computers:

  • Computers can only handle fixed data amounts and types.

  • Representation is limited to what meets computational needs.

2-Step Analog to Digital Conversion

1. Sampling (Discretization):

   • Converts continuous signals into discrete snapshots (e.g., video frames).

   • Illustrates how analog signals can be represented in samples.

2. Quantization (Truncation):

   • Converts infinite values to finite (e.g., rounding numbers like π).

Information Loss in Digital Representation

• Acknowledgment that some information is lost during digitization:

  • Users decide what can be lost initially.

  • Mechanisms exist for precise digitization, such as Nyquist-Shannon sampling theorem.

Bits and Bytes

• Bit: Binary digit holding a value of 0 or 1.

  • Grouped into bytes (8 bits) for data representation.

• Metric Prefixes: Used for larger data magnitudes such as Mb (megabit) or MB (megabyte).

Binary vs. Decimal Multipliers

• Differential understanding of how data transfer and communication are interpreted in decimal vs. binary metrics.

Benefits of Digital Technology

• Why Digital?

  • Computers require discretization, quantization due to noise limitations.

  • Binary representation simplifies processes and increases reliability.

Digital Signal Transmission and Storage Benefits

• Signal Transmission: Digital signals are less prone to degradation compared to analog signals, enabling regeneration.

• Storage and Compression: Digital copies maintain fidelity to the original and facilitate easier error correction and data compression due to identifiable patterns in data.