Protocols | OSI Model | Error Detection | Redundancy | Convolutional

Protocols Protocols are rules and procedures used to ensure compatibility between the sender and receiver of serial digital data regardless of the hardware and software being used. They are used to identify the start and end of a message, identify the sender and the receiver, state the number of bytes to be transmitted, state a … Read more

Ethernet LANs| Coaxial Cable | Twisted-Pair Cable | Advance Ethernet

Ethernet LANs One of the oldest and by far the most widely used of all LANs is Ethernet. Ethernet, which was developed by Xerox Corporation at Palo Alto Research Center in the 1970s, was based on the Aloha wide-area satellite network implemented at the University of Hawaii in the late 1960s. In 1980, Xerox joined … Read more

Network | Topologies | connectors | LAN | WAN | MAN | STAR | RING, BUS

Network Fundamentals A network is a communication system with two or more stations that can communicate with one another. When it is desired to have each computer communicate with two or more additional computers, the interconnections can become complex. As Fig. 12-1 indicates, if four computers are to be interconnected, there must be three links … Read more

Transmission Line | Cable | Connectors | Velocity Factor | Time Delay

Transmission Line Basics The two primary requirements of a transmission line are that (1) the line introduces minimum attenuation to the signal and (2) the line not radiate any of the signals as radio energy. All transmission lines and connectors are designed with these requirements in mind. Types of Transmission Lines Parallel-Wire Lines A parallel-wire … Read more

Active Filters | Crystal Filters | Ceramic Filters | Surface Acoustic Wave

What Are Active Filters? Active filters are frequency selective circuits that incorporate RC networks and amplifiers with feedback to produce a low-pass, high-pass, bandpass, and bandstop performance. These filters can replace standard passive LC filters in many applications. They offer the following advantages over standard passive LC filters. Gain. Because active filters use amplifiers, they … Read more

Standing Waves | Matched Lines | Circuit Elements | Stripline | Microstrip

Standing Waves Standing Waves: When a signal is applied to a transmission line, it appears at the other end of the line sometime later because of the propagation delay. If a resistive load equal to the characteristic impedance of a line is connected at the end of the line, the signal is absorbed by the … Read more

Smith Chart | Wavelength Scales | SWR Circle | Plotting and Reading

The Smith Chart Smith Chart: The mathematics required to design and analyze transmission lines is complex, whether the line is a physical cable connecting a transceiver to an antenna or is being used as a filter or impedance-matching network. This is so because the impedances involved are complex ones, involving both resistive and reactive elements. … Read more

Antenna | Antenna Operation | Antenna Types | Radio Waves | Dipoles

Radio Waves A radio signal is called an electromagnetic wave because it is made up of both electric and magnetic fields. Whenever voltage is applied to the antenna, an electric field is set up. At the same time, this voltage causes current to flow in the antenna, producing a magnetic field. The electric and magnetic … Read more

Radio Wave | Reflection | Refraction | Diffraction | Ground, Sky Waves

Radio Wave Propagation Radio Wave : Once a radio signal has been radiated by an antenna, it travels or propagates through space and ultimately reaches the receiving antenna. The energy level of the signal decreases rapidly with distance from the transmitting antenna. The electromagnetic wave is also affected by objects that it encounters along the … Read more

Internet Working | SONET | TCP/IP | Internet Transmission Systems

Internet Applications The Internet is a communication system that accomplishes one of three broad uses: (1) share resources, (2) share files or data, and (3) communication. The primary applications of the Internet are e-mail, file transfer, the World Wide Web, e-commerce, searches, Voice over Internet Protocol, and video. E-Mail E-mail is the exchange of notes, … Read more