A duplexer is an electronic device that allows bi-directional duplex communication over a single path. In radar and radio communications systems, it isolates the receiver from the transmitter while permitting them to share a common antenna. Most radio repeater systems include a duplexer. Duplexers can be based on frequency often a waveguide filter , polarization such as an orthomode transducer , or timing as is typical in radar. In the simplest arrangement, the switch consists of a gas-discharge tube across the input terminals of the receiver.
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A duplexer is an electronic device that allows bi-directional duplex communication over a single path. In radar and radio communications systems, it isolates the receiver from the transmitter while permitting them to share a common antenna. Most radio repeater systems include a duplexer.
Duplexers can be based on frequency often a waveguide filter , polarization such as an orthomode transducer , or timing as is typical in radar. In the simplest arrangement, the switch consists of a gas-discharge tube across the input terminals of the receiver. A hybrid , such as a magic T , may be used as a duplexer by terminating the fourth port in a matched load.
In radio communications as opposed to radar , the transmitted and received signals can occupy different frequency bands, and so may be separated by frequency-selective filters. With a duplexer the high- and low-frequency signals are traveling in opposite directions at the shared port of the duplexer. Modern duplexers often use nearby frequency bands, so the frequency separation between the two ports is also much less. Significant attenuation isolation is needed to prevent the transmitter's output from overloading the receiver's input, so such duplexers employ multi-pole filters.
There are two predominant types of duplexer in use - "notch duplexers", which exhibit sharp notches at the "unwanted" frequencies and only pass through a narrow band of wanted frequencies and "bandpass duplexers", which have wide-pass frequency ranges and high out-of-band attenuation.
On shared-antenna sites, the bandpass duplexer variety is greatly preferred because this virtually eliminates interference between transmitters and receivers by removing out-of-band transmit emissions and considerably improving the selectivity of receivers. Most professionally engineered sites ban the use of notch duplexers and insist on bandpass duplexers for this reason. Note 1: A duplexer must be designed for operation in the frequency band used by the receiver and transmitter, and must be capable of handling the output power of the transmitter.
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 C. The first duplexers were invented for use on the electric telegraph and were known as duplex rather than duplexer. They were an early form of the hybrid coil. The telegraph companies were keen to have such a device since the ability to have simultaneous traffic in both directions had the potential to save the cost of thousands of miles of telegraph wire.
Gintl's design was not very successful. The first really successful duplex was designed by Joseph Barker Stearns of Boston in This was further developed into the quadruplex telegraph by Thomas Edison. From Wikipedia, the free encyclopedia. Not to be confused with Diplexer.
For other uses, see Duplex disambiguation and Duplex printing. Main article: Circulator. Main article: Orthomode transducer. Radar for Meteorologists.
University of North Dakota. Radar engineers have added the automatic switch also called a duplexer in the As soon as the transmitter stops sending a signal, the duplexer switches so that the receiver is now connected to the antenna. New Delhi: New Age International. Categories : Broadcast engineering Radio electronics Electronic circuits Telegraphy Radio communications stubs.
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Cavity Duplexer Diplexer for Bts and RF Repeater System
Conversely, it can act as a splitter to enable the signal from one feeder to be connected to two receivers or antennas. Antenna diplexers are available in a variety of formats and within a range of different powers, so that they can meet the needs of a variety of different applications needs. Antenna diplexers find many uses. Diplexers can be used in a variety of different ways, so there is no method or way in which they must be used. Accordingly they can be used for a number of different applications. It should also be noted that a diplexer is different to the traditional form of power divider or splitter.
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Duplexer unit perform duplex operation of TX and RX signals through a common antenna and filters and amplifies main and diversity received signals before they pass through the Multi coupler unit to the TRx unit. It contains a variable-gain LNA for optimal amplification of the received signal. Duplexer is used for both transmission and reception of microwave frequencies in microwave. That means one information is transmit and one information is received by the antenna. Its more useful to communication field. Duplexer is a microwave device which is mainly used in radar system when same antenna act as both transmitter and receiver. Due to duplexer in bts it can communicate in both up link and down link.
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Transceiver consists of transmitter and receiver chain radio chain. Transmitter chain converts digital data to analog data, upconvert to radio frequency, and support other functions such as filtering and amplification etc. Receiver chain takes data from antenna, amplifies it, downconvert and finally it converts analog data to digital data. A duplexer typically consists of two band pass filters connected in parallel. One filter provides a path between the transmitter and the antenna, the other provides a path between the antenna and the receiver.
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