Search results
Results From The WOW.Com Content Network
The device is a tuned filter connected to the antenna. In this example, consider a type of device called a band-pass duplexer. It allows, or passes, a band, (or a narrow range,) of frequencies. There are two legs to the duplexer filter, one is tuned to pass the input frequency, the other is tuned to pass the output frequency.
Note 2: A duplexer must provide adequate rejection of transmitter noise occurring at the receive frequency, and must be designed to operate at, or less than, the frequency separation between the transmitter and receiver. Note 3: A duplexer must provide sufficient isolation to prevent receiver desensitization. Source: from Federal Standard 1037C
Repeaters are found mainly in the VHF 6-meter (50–54 MHz), 2-meter (144–148 MHz), 1.25-meter band (1 1 ⁄ 4 meters) (220–225 MHz) and the UHF 70 centimeter (420–450 MHz) bands, but can be used on almost any frequency pair above 28 MHz. In some areas, 33 centimeters (902–928 MHz) and 23 centimeters (1.24–1.3 GHz) are also used for ...
The 2-meter amateur radio band is a portion of the VHF radio spectrum that comprises frequencies stretching from 144 MHz to 148 MHz [1] in International Telecommunication Union region (ITU) Regions 2 (North and South America plus Hawaii) and 3 (Asia and Oceania) [2] [3] and from 144 MHz to 146 MHz in ITU Region 1 (Europe, Africa, and Russia).
Transformers, autotransformers, and baluns are sometimes incorporated into the design of narrow band antenna tuners and antenna cabling connections. They will all usually have little effect on the resonant frequency of either the antenna or the narrow band transmitter circuits, but can widen the range of impedances that the antenna tuner can match, and/or convert between balanced and ...
The ports of a diplexer are frequency selective; the ports of a combiner are not. There is also a power "loss" difference - a combiner takes all the power delivered to the S port and equally divides it between the A and B ports. A diplexer does not. A diplexer frequency multiplexes two ports onto one port, but more than two ports may be ...
In a radio receiver, a bandspread control is a secondary tuning control that allows accurate tuning of closely spaced frequencies of a radio band. [1] With a main tuning control that covered a wide range of frequencies, for example 10-14 megahertz in a few turns of the tuning knob, a very small motion might change the tuning by tens of kilohertz and would make accurate tuning to any particular ...
A frequency synthesizer is an electronic circuit that generates a range of frequencies from a single reference frequency. Frequency synthesizers are used in devices such as radio receivers , televisions , mobile telephones , radiotelephones , walkie-talkies , CB radios , cable television converter boxes , satellite receivers, and GPS systems.