DCS/WCDMA/GSM Multiplexer (MX-825-2170-06)

Cavity Filter

Features
Diplexer is the main accessory of hetero-frequency diplexer station and relay station. Its function is to isolate the transmitting and receiving signals, so as to ensure the receiving and transmitting can work normally at the same time.The Cavity Duplexer is composed of two bands of band-stop filters of different frequencies to prevent the local transmission of signals to the receiver. The general diplexer consists of six band-stop filters (notch filters), each resonating at the transmitting and receiving frequencies. The filter at the receiving end resonates the transmitting frequency and prevents the transmitting power from being strung into the receiver, while the filter at the transmitting end resonates at the receiving frequency. Some duplexer don't mark the launch and the receiving end and the only LOW and HIGH, such as a duplexer LOW = 450, HIGH = 460, said the LOW end can join 450 million 460 million transmitter, receiver HIGH end connection can also be will join 450 million transmitter LOW end, HIGH end connection 460 million receiver, sending and receiving frequency can be used upside down, but cannot meet the set will launch frequency 460 machine duplexer 450 million end so as not to damage the radio and duplexer. The diplexer is a special bidirectional three terminal filter. It not only needs to couple the weak receiving signal in, but also needs to feed the large transmitting power to the antenna, and requires the two to complete their respective functions without affecting each other. General duplexer consists of spiral cavity body, due to its high working frequency, distribution parameters influence often make it a gland body, all the signal feeder with good shielding effect of the coaxial cable of the cavity shape material also requires a certain degree of finish, is good for heat dissipation, appearance is often black, three commonly used standard high frequency signal end connectors Q9 or L16 type high frequency wireless communication requirement for duplexer socket. The operating frequency range of the diplexer shall not be narrower than that of the radio telephone itself. In general, the bandwidth refers to the input bandwidth of the receiver and the output bandwidth of the transmitter after the wireless telephone is equipped with a duplex. For a diplexer, it is the stopband bandwidth of two equivalent band-stop filters, rather than the passband bandwidth. As can be seen from its frequency response curve, it is the frequency range of the two stopbands at a certain attenuation. As is known to all, for today's VHF and UHF wireless telephones, the high-frequency input bandwidth of the receiver is generally above 5MHz, while the high-frequency output bandwidth of the transmitter is above 10MHz. That is to say, the high frequency input and output bandwidth of the wireless telephone itself is relatively wide, so the bandwidth of the duplexer is required to have a certain width, in order to overcome the trouble caused by the bandwidth problem when the user declares the frequency. However, according to the regulations of the radio frequency management departments in China and other countries in the world, a duplex wireless telephone set used as a dual-frequency duplex network has a transmitter-receiver frequency difference of 5.7mhz at 150MHz and 10MHz at 450MHz at 150MHz. Therefore, the ideal diplexer can only be half of the transceiver frequency difference specified by the corresponding frequency band of wireless telephone, that is, 150MHz is 2.85mhz and 450MHz is 5MHz.

Application Field
Our Cavity Duplexer has many advantages such as various size, wide frequency and low insertion loss.In the meantime,  it can also prevent impact and has excellent temperature stability. Due to its small size and light weight, it is used for mobile communication and as an unattended turntable in the field. However, the space provided by vehicle-mounted wireless telephone and automobile is limited, and the wiring and heat dissipation of the wireless telephone need to be considered. Therefore, the miniaturization of the duplexer is very necessary on the premise of meeting other technical indexes. Secondly, diplexers must be easy to install, especially for some diplexers and wireless phones. And should be solid, reliable, compact structure, should be able to withstand a certain impact and vibration, especially for some poor geographical environment of the local radio telephone. As we know, most current diplexers are required by distributed parameters to determine their working frequency and other indexes. If the structure of the diplexer cannot be adjusted, it may lead to the deterioration of the whole machine index of the wireless telephone, or even burn out the receiver. This is particularly important. Moreover, as a medium turntable sometimes use environment is quite harsh, which requires that the duplexer can also ensure the quality of communication within the corresponding operating temperature range. Generally speaking, the diplexer should have a clear operating temperature range and a stability index of temperature change, so as to meet the requirements of the whole machine. The debugging of the duplex refers to that the duplex should confirm whether the working frequency is consistent with the working frequency of the wireless telephone before the whole machine is tuned. If there is a big difference, it should be adjusted and adjusted again to avoid burning out the input high-amplifier circuit. In the debugging stage of the whole machine, after the circuit board of transceiver is adjusted, the duplexer should be carefully fine-tuned to maximize the transmission power and minimize the deterioration of transmission and reception sensitivity. Watch out for small, slow adjustments to prevent satellite TV from burning out. Because the diplexer operates at a high frequency and is a component whose characteristics are determined by distributed parameters, it is very sensitive to adjustment. And to prevent the adjustment after the lock, in the process of the original adjustment of the best point to run. Some duplicators use self-locking screws, do not have to use additional nuts to lock, so that debugging is very convenient, and save the man-hour cost. The purpose of adjusting the diplexer is to delete the transmitting signals between the antenna and the receiving circuit, and at the same time to achieve the minimum pass-band signal decay between the antenna and the receiving circuit. The steps of adjustment and test are as follows: first, the high-frequency signal generator outputs the high-frequency point, and the low-pass screw of the diplex is adjusted to slowly weaken the signal received by the receiver, so that the output of the signal generator will not lead to the saturation of the receiver. If necessary, the output of the high frequency signal generator can be gradually enhanced. Meanwhile, the receiver can be adjusted to the critical noise-quiet receiving state. Then, the position of the load and the receiver is exchanged, the signal generator outputs low-frequency points, while the receiver receives low frequency points. The high-pass screw of the diplexer is adjusted to weaken the signal received by the receiver slowly, so that the signal generator output will not lead to receiver saturation. If necessary, the output of high frequency signal generator can be enhanced. The process can be repeated several times to achieve the best isolation of the diplexer. Its function is to isolate the transmitting and receiving signals, so that both can work normally at the same time. The diplexer not only needs to couple the weak receiving signal in, but also needs to feed the large transmitting power to the antenna, and requires the two to complete their respective functions without affecting each other. Therefore, debugging is very important. The duplexer belongs to the filter for communication equipment, and belongs to the class of sound meter filter. The main function is to isolate the transmitting and receiving signals, so as to ensure that the frequency of the transmitting signal and the frequency of the receiving signal do not interfere with each other. Internally, there are two groups of band-stop filters, and the frequencies of the two groups of filters are different from each other, so as to realize the non-interference between the sending frequency and the receiving frequency. Because it works in both directions, it is called a duplexer.

Specifications

It is a component for frequency selecting with both frequency transmitting and receiving updated from design of cavity filter.