Mobile phone wireless communication test technology uses spectrum analyzer
The vibration of the object produces sound → sound waves are transmitted in the air, → Soundproof Insulation Fiber Glass Wool,Heat Resistant Rubber Insulation Cotton → sound waves are reflected, superimposed and collided by countless fibers when passing through cotton, and sound energy is converted into heat energy → sound intensity is weakened → sound disappears. The transmitted sound energy is attenuated to 3 / 10 ~ 4 / 10 or less of the incident sound energy.
Soundproof Insulation Fiber Glass Wool,Heat Resistant Rubber Insulation Cotton,Water-Proofing Sound Insulation Cotton,Energy Saving Sound Insulation Cotton Zhengzhou Ou Nuo Building Materials Co., Ltd. , https://www.jcyuounuo.com
Question 1: Each communication carrier has to control its own communication band
ITU has a strict definition of the frequency bands of communications, and communication methods such as industrial and scientific communications, fixed and mobile services, and satellite communications must be carried out in their respective frequency bands, even in the same frequency band. Definition. If the bandwidth of the communication band exceeds the range allocated by itself, it will not only interfere with other communication but also affect its own communication energy. Therefore, it is necessary to test the bandwidth of communication and the concentration of signal energy.
Question 2: Need to ensure the quality of communication signals
When the mobile phone wirelessly communicates, various noises are mixed in the channel, and the noise causes the quality of the communication signal to deteriorate, so the signal-to-noise ratio of the communication channel needs to be measured.
Question 3: There will be respiratory effects and near-far effects in mobile wireless communication systems.
In a wireless communication system, when the interference signal in one cell is strong, the actual effective coverage area of ​​the base station is reduced; when the interference signal of one cell is weak, the actual effective coverage area of ​​the base station becomes larger, which is Breathing effect. In short, the respiratory effect is manifested by a contraction radius that increases as the number of users increases. Since mobile phone users are randomly distributed in a cell and are constantly changing, the same mobile phone user may sometimes be at the edge of the cell, sometimes close to the base station. If the transmission power of the mobile phone is designed according to the maximum communication distance, when the mobile phone is close to the base station, the power must be excessive, and harmful electromagnetic radiation is formed, which is the near-far effect. The solution to this problem is to adjust the transmission power of the mobile phone, that is, the power control, in real time according to the communication distance. This requires real-time monitoring of the size of the communication signal.
The spectrum analyzer can solve the above three problems well. The following is an example of how to perform the test by taking the DSA1030A spectrum analyzer introduced by RIGOL. The DSA1030A spectrum analyzer has a frequency range of 9 kHz to 3 GHz, a display average noise level of -148 dBm, a typical phase noise of -88 dBc/Hz @ (offset 10 kHz), and a full-amplitude accuracy of less than 1.0 dB, which can help solve mobile phone applications. The problem. At the same time, the DSA1030A spectrum analyzer also has a rich one-button measurement function to meet a variety of complex needs. The following is an example of testing a TD-SCDMA signal to illustrate the role of the spectrum analyzer.
For problem one and problem two, the ACP adjacent channel power measurement and OBW occupied bandwidth measurement in the DSA1030A spectrum analyzer can be used to solve. The lead power measurement can measure the main channel power, the power of the previous channel and the latter channel, and the signal-to-noise ratio measurement between the main channel and the upper and lower adjacent channels. The measurement result is shown at the lower left in FIG. The user flexibly sets the bandwidth of the main channel, the adjacent channel bandwidth, and the spacing between the main channel and the adjacent channel according to specific needs. The lower right side of Fig. 1 is the measurement setting value. By using the function of the lead power measurement, the energy of the channel communication and the signal-to-noise ratio of the communication can be clearly measured. From Fig. 1, it can be concluded that the main channel energy is -10.69 dBm and is basically concentrated in the bandwidth of 1.6 MHz, which is consistent with the requirement that the bandwidth of each carrier of the TD-SCDMA signal is 1.6 MHz. Adjacent channel suppression is -51.32dB and -51.66dB, which can meet the general needs.
The OBW Occupied Bandwidth feature can detect if the energy of the part of interest is within a certain bandwidth. By setting the power ratio to 99%, the signal is measured to contain 99% of the energy in the bandwidth of 1.396666 MHz.
For Problem 3, the Pass/Fail function in the DSA1030A spectrum analyzer can be used to solve this problem. The user edits the two standard traces, that is, the upper and lower limits of the measurement, in advance according to actual needs. When the function is enabled, the measurement result will be statistically passed. When the measurement fails, the measurement will stop automatically and the frequency and amplitude of the measurement failure will be checked. As shown in Figure 3, the signal is monitored using the Pass/Fail function.
For the above measurements, the DSA1030A also provides the loading of humanized operational measurements and the loading of measurement settings. The user can save the measured settings to the local and wait for the next measurement to load directly. This can reduce operating time, reduce the chance of operating errors, and improve measurement efficiency. It is also possible to save the measurement settings to a USB flash drive and load them into other spectrum analyzers to facilitate the migration of the measurement. The user can edit the measurement settings in the laboratory and save them to the U disk in advance and then directly transplant them to the instrument at the measurement site. The measured results can also be saved from the instrument to the computer via a USB flash drive for later analysis or as report data.