Search results
Results from the WOW.Com Content Network
A radio-frequency power amplifier (RF power amplifier) is a type of electronic amplifier that converts a low-power radio-frequency (RF) signal into a higher-power signal. [1] Typically, RF power amplifiers are used in the final stage of a radio transmitter , their output driving the antenna .
Stubs are commonly used in antenna impedance matching circuits, frequency selective filters, and resonant circuits for UHF electronic oscillators and RF amplifiers. Stubs can be constructed with any type of transmission line: parallel conductor line (where they are called Lecher lines), coaxial cable, stripline, waveguide, and dielectric waveguide.
These "Hi-Z" or "instrument" inputs generally have higher gain than a line input. They are designed to be used with, for example, electric guitar pickups and " direct injection " boxes. Some of these sources can provide only minimal voltage and current and the high impedance input is designed to not load them excessively.
The AT&T receiving Beverage antenna (left) and radio receiver (right) at Houlton, Maine, used for transatlantic telephone calls, from a 1920s magazine. The Beverage antenna or "wave antenna" is a long-wire receiving antenna mainly used in the low frequency and medium frequency radio bands, invented by Harold H. Beverage in 1921. [1]
Those RTs with power settings can vary transmission range from approximately 200 meters (660 feet) to 10 kilometers (km) (6.2 miles). Adding a power amplifier increases the line of sight (LOS) range to approximately 40 km (25 miles). (These ranges are for planning purposes only; terrain, weather, and antenna height can affect transmission range.)
Characteristic modes (CM) form a set of functions which, under specific boundary conditions, diagonalizes operator relating field and induced sources.Under certain conditions, the set of the CM is unique and complete (at least theoretically) and thereby capable of describing the behavior of a studied object in full.
An antenna creates sufficiently strong electromagnetic fields at large distances. Reciprocally, it is sensitive to the electromagnetic fields impressed upon it externally. The actual coupling between a transmitting and receiving antenna is so small that amplifier circuits are required at both the transmitting and receiving stations.
A bias tee is a three-port network used for setting the DC bias point of some electronic components without disturbing other components. The bias tee is a diplexer.The low-frequency port is used to set the bias; the high-frequency port passes the radio-frequency signals but blocks the biasing levels; the combined port connects to the device, which sees both the bias and RF.