Communication Engineering - Types of Noise in Communication

Summary

This video on communication engineering discusses the concept of noise in communication systems. Noise, defined as an unwanted signal that interferes with the original signal, can degrade the quality and performance of communication. The video explains the two main types of noise: external and internal, detailing their sources, effects, and classifications. External noise comes from outside the system, such as atmospheric and industrial noise, while internal noise is generated within the system components. The video also elaborates on various noise types, including thermal, flicker, and partition noise, and their impact on communication systems.

Takeaways

• 📢 Noise is an unwanted signal that interferes with the original message signal, corrupting its parameters.
• 🌐 Noise can enter a communication system either through the channel or the receiver.
• 📉 Noise is random, unpredictable, and lacks a specific pattern, frequency, or amplitude, making it difficult to fully eliminate.
• 📻 Common effects of noise include hiss in radio receivers, snow in TV receivers, and buzz in telephonic conversations.
• 📊 Noise affects the performance of communication systems by limiting operating range, reducing sensitivity, and impacting overall system performance.
• 🔍 Noise is classified into two broad groups: external noise (from sources outside the communication system) and internal noise (from within the system).
• 🌩️ External noise includes atmospheric noise (e.g., lightning and thunderstorms), industrial noise (e.g., electrical equipment), and extraterrestrial noise (e.g., solar and cosmic radiation).
• ⚙️ Internal noise originates from the components within the communication system and includes shot noise, partition noise, flicker noise, transit time noise, and thermal noise.
• 🔥 Atmospheric noise occurs mainly in low and medium frequency bands, while industrial noise is prevalent in urban and industrial areas.
• 🔧 Internal noise can be reduced through proper receiver design, and types like thermal noise are caused by the random motion of molecules and electrons.

Q & A

What is noise in communication systems?

Noise is an unwanted signal that interferes with the original message signal, corrupting its parameters. It can enter either through the communication channel or at the receiver, making it difficult to predict or eliminate completely.

How does noise affect the quality of a communication signal?

Noise causes fluctuations in the signal, making it unpredictable and random. It limits the operating range, sensitivity, and overall performance of the communication system, impacting signal quality.

What are the two broad categories of noise in communication systems?

Noise is broadly categorized into two types: external noise and internal noise. External noise originates outside the communication system, while internal noise is generated within the system or receiver components.

What is external noise and how is it classified?

External noise is generated outside the communication system and cannot be controlled or eliminated. It is classified into atmospheric noise, extraterrestrial noise, and industrial noise, all of which impact signal quality.

What causes atmospheric noise, and how does it affect communication?

Atmospheric noise, also known as static noise, is caused by natural phenomena such as lightning and thunderstorms. It spreads across a wide frequency spectrum, especially affecting low and medium frequencies.

What is industrial noise and how can it be reduced?

Industrial noise, also called man-made noise, is produced by electrical devices such as motors, switch gears, and transmission lines. It is prevalent in industrial areas and can be statistically analyzed, but reducing it requires shifting the communication system to less populated areas.

What is solar and cosmic noise, and how do they impact communication?

Solar noise comes from the sun, which radiates electrical energy due to its high temperature. Cosmic noise originates from distant stars, which also emit thermal noise. Both contribute to external noise in space-based communication.

What is internal noise and how does it differ from external noise?

Internal noise is generated by components within the communication system or receiver. Unlike external noise, it can be quantified, and its effects can be reduced through careful receiver design.

What is thermal noise, and why is it called 'white noise' or 'Johnson noise'?

Thermal noise, also known as white noise or Johnson noise, is a random noise generated in resistive components due to the random motion of electrons. It is constant across a wide frequency spectrum and affects signal quality.

How can internal noise, such as partition or flicker noise, be minimized in communication systems?

Partition noise occurs when current divides between two paths, and flicker noise increases as frequency decreases. Using less noisy components, such as MOSFETs, and optimizing circuit design can help reduce these types of internal noise.