Search results
Results from the WOW.Com Content Network
Bell Laboratories Layer Space-Time (BLAST) is a transceiver architecture for offering spatial multiplexing over multiple-antenna wireless communication systems. Such systems have multiple antennas at both the transmitter and the receiver in an effort to exploit the many different paths between the two in a highly-scattering wireless environment.
Circuit components such as amplifiers can be tested using the two-tone method with a test setup like that shown in the figure. Two signal generators, set to two different frequencies F1 and F2, are fed into a power combiner through circulators. The combiner needs to have good isolation to prevent the signal from one generator being sent to the ...
Mobile phone towers also often take advantage of diversity - each face (sector) of a tower will often have two antennas; one is transmitting and receiving, while the other is a receive only antenna. Two receivers are used to perform diversity reception. Cell antennas on an electricity pylon showing two antennas per sector. The use of multiple ...
At one time, in wireless the term "MIMO" referred to the use of multiple antennas at the transmitter and the receiver. In modern usage, "MIMO" specifically refers to a class of techniques for sending and receiving more than one data signal simultaneously over the same radio channel by exploiting the difference in signal propagation between ...
The television broadcast bands are too wide in frequency to be covered by a single antenna, so the two options are separate antennas used for the VHF and UHF bands or a combination (combo) VHF/UHF antenna. [6] A VHF/UHF antenna combines two antennas feeding the same feedline mounted on the same support boom.
Antenna directivity is the ratio of maximum radiation intensity (power per unit surface) radiated by the antenna in the maximum direction divided by the intensity radiated by a hypothetical isotropic antenna radiating the same total power as that antenna. For example, a hypothetical antenna which had a radiated pattern of a hemisphere (1/2 ...
Multiple-input, multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) is the dominant air interface for 4G and 5G broadband wireless communications. It combines multiple-input, multiple-output technology, which multiplies capacity by transmitting different signals over multiple antennas, and orthogonal frequency-division multiplexing (OFDM), which divides a radio channel into ...
However, some devices, especially wireless cameras, operate with (often unauthorized) high power levels, and have high-gain antennas. [ citation needed ] Amateur radio operators can transmit two-way amateur television (and voice) in the 2.4 GHz band—and all ISM frequencies above 902 MHz—with maximum power of 1500 watts in the US if the ...