Communication Systems Fundamentals and Modulation Techniques
1. Communication System Definition and Block Diagram
A communication system is a setup used to transmit information from a source to a destination. The general block diagram includes the following functional elements:
- Information Source: Produces the message to be transmitted (e.g., voice, text, video).
- Input Transducer: Converts the message (if non-electrical) into a time-varying electrical signal.
- Transmitter: Processes the electrical signal for transmission. Its main function is modulation, where
Fundamentals of Modulation Techniques in Communication Systems
1. Modulation and Its Necessity
Modulation
Modulation is the process of varying a high-frequency carrier signal according to the low-frequency message (baseband) signal.
Need for Modulation
To reduce the size of the antenna (Antenna height is proportional to $\lambda/4$; without modulation, the antenna height becomes hundreds of meters).
To avoid mixing of signals (different stations use different carrier frequencies).
To increase the range of communication (High-Frequency carriers travel longer distances)
Microwave Technology: Applications, Devices, and Transmission Lines
Applications of Microwaves||Common applications (any 5–6 can be written)||–
Radar (Radio Detection and Ranging)||– Satellite communication||– Terrestrial microwave links (point-to-point communication)||–
Microwave ovens (domestic and industrial heating)||– Remote sensing and radiometry||– Medical applications (diathermy, cancer treatment, imaging)||– Radio astronomy and deep-space communication||– Military EW (jamming, guidance, seekers)||Brief explanation of any two:||1.Radar (Radio Detection
Essential Components and Transmission Modes in Communication Systems
Fundamentals of Data Communication Systems
Data Transmission Modes
These modes define the directionality of data flow between devices:
- Simplex Communication: If the roles of transmitter and receiver are clearly defined, data transmission is always carried out in one direction from sender to receiver. Example: Television (TV) broadcasting.
- Half-Duplex Communication: Communication may be bidirectional, but it cannot be simultaneous. Example: Two-way radio.
- Full-Duplex Communication: Two-way simultaneous
Workshop
We say that there is a surge when the nominal voltage of 220VAC, a certain percentage goes up and stays there for a certain period of time say that there are tensions Low Low voltage when the nominal value of 220 VAC, low a percentage and maintained at that value over a period of time peaks, transients and electrical noise or transient spikes appear in the power line for example when switched on or off electric motors. It appears as a very sudden surge of very high value during a tiny period of
Read MoreDigital Modulation and Data Transmission Methods
Modulation is called the transaction by which certain characteristics of a wave called a carrier, be modified in light of another wave called modules, which contains information
The modulation process requires two signals, Modules and carriers, and as a result generates a third signal, called the modulated signal.
The carrier signal parameters that are affected by the information are: MODULATION
FSK
MODULATION DIGITAL-ANALOG
FSK (modulation frequency shift): It changes the carrier frequency depending
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