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

Storage Area Networks | SCSI | Internet Security | Security Measures

Storage Area Networks Storage area networks (SANs) are one of the faster-growing segments of data communications. SANs and similar storage systems provide a way to meet the Internet’s nearly insatiable need for data storage. Besides the need for mass storage of data for websites and e-mail, there is a growing demand for storage at large … Read more

Microwave Concepts | Communication Systems | Size and Frequency

Microwave Concepts Microwave are the ultrahigh, super high, and extremely high frequencies directly above the lower frequency ranges where most radio communication now takes place and below the optical frequencies that cover infrared, visible, and ultraviolet light. The outstanding benefits for radio communication of these extremely high frequencies and accompanying short wavelengths more than offset … Read more