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Spektrum is a brand of radio control systems designed for use with hobby radio-controlled cars and aircraft. Spektrum is a division of Horizon Hobby . The R/C hobby in the United States, Japan, and Europe typically used to employ FM radio control in HF and VHF bands such as 27 MHz, 35 MHz, 49 MHz, and 72 MHz.
Spektrum DX6i 6-channel spread spectrum computerized aircraft radio which may be used for both helicopters and fixed-wing models Starting with the Spektrum DX6 park flyer transmitter system in 2006, RC flying began the departure from various lower frequencies which were subject to interference and were less reliable than the new spread spectrum ...
The transmitter and receiver can use fixed tables of frequency-hopping patterns, so that once synchronized they can maintain communication by following the table. In the US, FCC part 15 on unlicensed spread spectrum systems in the 902–928 MHz and 2.4 GHz bands permits more power than is allowed for non-spread-spectrum systems.
This is commonly used in conjunction with a receiver and analog-to-digital converter. As above, the receiver reduces the center-frequency of a portion of the input signal spectrum, but the portion is not swept. The purpose of the receiver is to reduce the sampling rate that the analyzer must contend with.
For convenience, these figures may also be expressed as 1 nautical mile in 12.4 μs or 1 kilometre in 6.7 μs. (For simplicity, all further discussion will use metric figures.) If the radar pulse width is 1 μs, then there can be no detection of targets closer than about 150 m, because the receiver is blanked.
Graphs illustrating the problem of image response in a superheterodyne. The horizontal axes are frequency and the vertical axes are voltage. Without an adequate RF filter, any radio signal S2 (green) from the antenna at the image frequency is also heterodyned to the IF frequency along with the desired radio signal S1 (blue) at , so they both pass through the IF filter (red).
The AN/ARC-5 Command Radio Set is a series of radio receivers, transmitters, and accessories carried aboard U.S. Navy aircraft during World War II and for some years afterward. It is described as "a complete multi-channel radio transmitting and receiving set providing communication and navigation facilities for aircraft.
Transitions between modes and/or antenna connections are signaled by a change in the perceived quality of the link. In situations of low fading, the receiver can employ no diversity and use the signal presented by a single antenna. As conditions degrade, the receiver can then assume the more highly reliable but power-hungry modes described above.