Digital Transmission Lecture Review

These flashcards cover key concepts and terminology related to digital transmission, focusing on line coding, encoding schemes, transmission modes, and essential principles such as sampling and synchronization.

What is line coding?

The process of converting sequences of binary data (i.e., bits) into digital signals.

What are the key characteristics of line coding?

Signal level vs. Data level, Pulse rate vs. Bit rate, DC components, Self-synchronization.

What is the difference between signal levels and data levels?

Signal levels refer to the number of values used to represent a signal, while data levels refer to the number of values used to represent the data.

How is the pulse rate defined?

Pulse rate (Baud) is the number of pulses transmitted per second.

What is the relation between Bit Rate and Pulse Rate?

Bit Rate = Pulse Rate x Log2 (L), where L is the number of data levels.

What does the DC component in line coding refer to?

Excess energy in the line caused by unbalanced data levels that does not carry information and may cause distortion.

What is self-synchronization in digital signals?

A method where timing information is embedded in the transmitted signal for the receiver to identify signal transitions.

What are the types of line coding schemes?

Unipolar, Polar (NRZ-L, NRZ-I, RZ, Manchester, Differential Manchester), Bipolar (AMI, BnZS).

What is the advantage of Return to Zero (RZ) encoding?

Synchronization is guaranteed by every bit.

What is Pulse Amplitude Modulation (PAM)?

A technique that samples an analog signal and generates pulses, but is not useful for data communications on its own.

What does the Nyquist Theorem state about sampling rate?

The sampling rate should be at least twice the highest frequency component in the original analog signal.

What are the two types of data transmission?

Parallel transmission (multiple bits at once) and Serial transmission (one bit at a time).

How does asynchronous transmission work?

It sends a start bit at the beginning and one or more stop bits at the end of each byte, allowing for gaps between bytes.

What is the difference between synchronous and asynchronous transmission?

In synchronous transmission, bits are sent continuously without start/stop bits, while asynchronous transmission includes start and stop bits.

What is block encoding?

A process of stuffing a bit stream with redundant bits to ensure synchronization and detect errors.

What does 4B/5B code do?

It substitutes every 4-bit block of data with a 5-bit code to limit the number of consecutive 0's.