The working principle of mobile phone signal amplifier

　　Downlink: Outdoor Yagi receives useful signals that can be used for calls (generally mobile phones display 4 grids), input them to the host, and the host sends it to the indoor ceiling antenna after amplification, and then

　　Radiation through the antenna to the user's mobile phone, this is the downlink. Uplink: The user's mobile phone transmits signals, which are absorbed by the ceiling antenna and input to the host, and then amplified by the host, and then

　　Send it to the outdoor Yagi or plate antenna to transmit to the base station, which is the uplink.

　　Mobile phone signal amplifier installation and use rules

　　(GSM900MHZ communication system needs to use GSM mobile phone signal amplifier, GSM mobile phone signal amplifier general frequency uplink 890MHZ-915MHZ, downlink 925

　　-935MHZ. DCS1800MHZ communication system needs to use DCS mobile phone signal amplifier, DCS mobile phone signal amplifier general frequency: Uplink 1710-1785M

　　HZ, the downlink frequency is 1805-1880MHZ. Of course there are 3G communication systems, CDMA communication systems, TD-SCDM communication systems, W-CDMA communication systems, etc.

　　These must choose the corresponding mobile phone signal amplifier. Make sure to install the signal (-60DBM) above the outdoor antenna end of the mobile phone signal amplifier, and ensure the outdoor antenna

　　The distance between the terminal and the communication company (transmitting station, cellular station, base station) is within 5 kilometers. The high-frequency signal transmission cable from the outdoor antenna to the amplifier needs to be 50 ohm-7G

　　The above coaxial cable, and ensure that the line shall not exceed 50 meters. (The outdoor antenna must be consistent with the output frequency of the mobile phone signal amplifier, generally a Yagi directional antenna)

　　The high-frequency signal transmission cable from the amplifier to the indoor antenna should be a 50 ohm-7 coaxial cable, and the farthest line must not exceed 80 meters. (The indoor antenna must be connected to the mobile phone

　　The output frequency of the signal amplifier is consistent, generally using ceiling mushroom antenna) The frequency of the power splitter selected for indoor coverage needs to be greater than the frequency of the installed amplifier

　　(Generally choose 800-2500MHZ distributor, because this kind of distributor almost contains the frequency of all current communication networks).

　　1. The installation position of the outdoor antenna must be able to make calls clearly, and the installation of Yagi is generally horizontal.

　　2. The distance between Yagi and the ceiling antenna should be as wide as possible, greater than 8 meters, and not within the same line of sight to avoid self-excitation. Typically, walls are used for isolation.

　　The effect is good.

　　3. For 50-5 coaxial cable, the F head is usually transferred to the host. It should be absolutely ensured that the F head is fastened and fully grounded. This effect will be more obvious.

　　4. The F head must be a 50-5 inch cable. It should also be matched with a 50-5 coaxial cable, otherwise there will be problems that cannot be installed. The main performance indicators of mobile phone signal amplifier

　　The signal amplifier is used to amplify mobile phone signals, and its performance is measured by its technical indicators. There are many technical indicators of mobile phone signal amplifiers, and there are five main performance indicators.

　　Output power, gain, automatic gain control Rated (maximum) output power, rated (maximum) gain (and gain adjustment range, automatic gain control range) and input

　　Level. This is a set of interrelated indicators and should be considered comprehensively. Usually the maximum output power does not exceed the maximum limit specified by the Radio Regulatory Bureau of the Ministry of Information Industry

　　, Should be divided into several levels for users to choose, the downlink mainly considers coverage, and the uplink ensures satisfactory reception by the base station. Therefore, the downlink is generally greater than the uplink. Gain is the amount of information received

　　The signal is amplified to the rated output power. Taking into account the difference in signal strength at the installation site of the repeater, the gain should be adjustable. The maximum gain can consider the signal received by the repeater

　　The level is amplified to the maximum output power to calculate. In order to ensure stable output power and avoid output nonlinearity, automatic gain control (AGC) with ≮20dB seems to be necessary

　　need. Regarding the tolerance, rated output power and rated gain, it is sufficient to specify one. It is generally appropriate to specify the gain tolerance. Because the gain is adjusted to

　　Maximum, change the input level to make the output reach the rated value. In this case, of course, the rated power does not have to specify the tolerance, and at this time, the input level is also affected by the difference in gain.

　　different. (Yagi standing wave: about 1.8-2.0. Panel standing wave: within 1.4. Panel gain is about 7dB, Yagi is about 10dB. The gain of the host is generally about 50-70dB.

　　. ) Working frequency band The working frequency bands of mobile phone signal amplifiers of different systems are different. For example, the working frequency bands of China Unicom, China Telecom, and China Mobile are all independent. (Yagiten

　　Line frequency: The frequency is relatively narrow, such as: 800-1000MHz Yagi antenna is different from 1800-2000MHz antenna. What kind of antenna can only be used for what frequency

　　. The frequency of the panel antenna: 800-2500MHz, suitable for all mobile phone signals. ) Bandwidth, in-band fluctuation This is a set of indicators that are related to each other, especially with

　　Wide and in-band fluctuations. Generally, the bandwidth refers to the -3dB bandwidth, and the in-band fluctuation refers to the unevenness in the band. If the in-band fluctuation is required to be smaller than 3dB, the -3dB bandwidth must

　　However, it is wider than the bandwidth allocated to it, so that it is bound to invade other channels. Therefore, the maximum in-band fluctuation can only be 3dBp-p. Out-of-band suppression Out-of-band suppression is mainly for

　　Requirements of filter shape. In order not to cause interference to others, it is desirable that the shape of the filter is as close to a rectangle as possible. Usually the ratio of -60 (or -40) dB bandwidth to -3dB bandwidth

　　Some people call it the shape coefficient of the filter). Intermodulation and spurious emission harmonics, intermodulation and spurs are undesirable and useless signals, and the same requirements can be put forward.

　　For GSM mobile phone signal enhancer, it is suitable according to the requirements of YD/T 883-1999 and ETS 300 609. For CDMA mobile phone signal enhancer, only according to YD/T 1047-

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