Search results
Results From The WOW.Com Content Network
A radio transmitter design has to meet certain requirements. These include the frequency of operation, the type of modulation, the stability and purity of the resulting signal, the efficiency of power use, and the power level required to meet the system design objectives. [1]
In the box at the focus of the dish, called a low-noise block downconverter (LNB), each block of frequencies is converted to the IF range of 950–2150 MHz by two fixed frequency local oscillators at 9.75 and 10.6 GHz. One of the two blocks is selected by a control signal from the set top box inside, which switches on one of the local oscillators.
4×4 array of 2.4 GHz patch antenna elements Patch antenna gain pattern. A patch antenna is a type of antenna with a low profile, usually consisting of a printed circuit board. It consists of a planar rectangular or circular sheet or "patch" of metal, mounted over a larger sheet of metal called a ground plane.
In electronics, an antenna amplifier (also: aerial amplifier or booster) is a device that amplifies an antenna signal, usually into an output with the same impedance as the input impedance. Typically 75 ohm for coaxial cable and 300 ohm for twin-lead cable. An antenna amplifier boosts a radio signal considerably for devices that receive radio ...
Loops of any size between 10% and 30% of a wavelength in perimeter, up to almost exactly 50% in circumference, can be built and tuned with series capacitors to resonance, but their non-uniform current will reduce or eliminate the small loops' pattern null. A capacitor is required for a circumference less than a half wave, and an inductor is ...
Schematic of an AGC used in the analog telephone network; the feedback from output level to gain is effected via a Vactrol resistive opto-isolator.. Automatic gain control (AGC) is a closed-loop feedback regulating circuit in an amplifier or chain of amplifiers, the purpose of which is to maintain a suitable signal amplitude at its output, despite variation of the signal amplitude at the input.
The idea is to find how much the amplifier gain is changed because of the resistors in the feedback network by themselves, with the feedback turned off. This calculation is pretty easy because R 11, R B, and r π1 all are in parallel and v 1 = v π. Let R 1 = R 11 || R B || r π1. In addition, i 2 = −(β+1) i B. The result for the open-loop ...
The diamond buffer was used in commercial audio line-level and headphone preamplifiers (e.g. the Lehmann Cube series and its clones), but did not see much use in commercial audio power amplifiers. The Accuphase current-feedback power amplifiers of the 1990s employed the diamond buffer in the input stage, but not the output stage. [19]