Formula for the relationship between attenuation and distance of Wi-Fi wireless signal transmission [Indoor Location]
Calculation of wireless communication distance1. DBM dbmv dbuv Conversion RelationshipDBM = 10log (pout/1 MW), where pout is the power value in the unit of MWDbmv = 20log (Vout/1mV), where Vout is the voltage value in the unit of MVDbuv = 20log (Vout/1uv), where Vout is the voltage value in the unit of UVConversion Relationship:Pout = Vout × Vout/RDbmv = 10log (R/0.001) + dBm, r
article, we mentioned that a user installs a receiving and sending antenna on the office and home roof to communicate with the base station BTS through LOS. In recent years, FWA has made significant improvements in technical design, striving to achieve "Non-line-of-sight transmission" NLOS and Non-LOS ), it is no longer required that the user's receiving and sending antennas must be installed at the high point on the roof, but to allow the antennas t
subtraction between DB and DB in the project, without multiplication and division. The most commonly used method is subtraction: dBm minus D.In fact, BM is divided by two power sources. signal power and noise power are divided by signal-to-noise ratio (SNR ). DBM + dBmIt is a multiplication of two power values. This is rare (I only know that this is an Application in Power Spectral convolution ).What is dBm multiplied by DBM? 1 MW is the power of 1 MW? Except for the old classmates who wrote th
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EMI test Project-re radiation emission
In the re test, the height of the antenna, the polarization direction of the antenna and the angle of the turntable need to be constantly changed in order to find the maximum radiation point of the device.
The RE test can be carried out in a semi-electric dark room in an
. Consider forcing the network portal to require users to run antivirus software. Then set the allowed destinations, ports and URLs, optionally adding bandwidth throttling and wired/wireless properties. Finally, consider whether guest traffic needs to be bridged to a VLAN or routed to the Internet when local area network access is allowed or not allowed. The cloud controller can analyze traffic to see how the wireless guest network is being used. These features are typically used for unencrypt
mobile phone, when answering the phone can always feel the phone front shell shaking, this is the mobile phone structure design problems, because the cell phone's shell is too thin, the speaker vibration is easy to make the phone's fuselage resonance.3.HW (Hardware) Hardware designThe hardware mainly designs circuits as well as antennas, while HW is to maintain regular communication with MD. For example, the MD requires thin, so the circuit is also thin to make sense. At the same time HW will a
parameter in the GNSS-SDR.
GNSS-SDR.internal_fs_hz=corrected_valueInputFilter.sampling_frequency=corrected_valueResampler.sample_freq_in=corrected_valueResampler.sample_freq_out=corrected_value
0x05 GPS active antenna
The security researcher uses a Low Noise Amplifier (Low Noise Amplifier LNA) antenna with a ceramic patch day as an active GPS antenna to re
about 3 minutes to transmit MB of files. In the same environment, it takes about 30 seconds to transmit MB of files for 802.11g-supported products. Therefore, when purchasing a product, you should also consider floating Based on the transmission rate you need.
Wireless Router-signal coverage
That is, the "valid working distance" mentioned in the example router parameters is one of the important parameters of the wireless router. As the name suggests, it is only within the signal coverage of the
, and the dwpts length of 2nd half frames is 1 ms. Uppts and sub-frame 2 are used as the uplink, and sub-Frames 7 and 9 are used as the downlink.Physical resources
Basic time unit
Antenna Port
LTE uses antenna ports to differentiate space resources. The definition of an antenna port is defined from the receiver's perspective. That is, if the receiver needs to
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What is the effective omni-direction radiation power?
In fact, the directional transmitting antenna is often used, so that the transmitter power is concentrated in a particular direction and the energy is greatly enhanced in this particular direction.
assuming that the energy in a particular direction is greater than the non-directi
Conversion of wireless power mW and DBM and interpretation of common symbols
1. Conversion of power unit mW and DBM The RF signal output by the radio transmitter is transmitted to the antenna through a feeder (Cable), which emits electromagnetic waves. After the electromagnetic wave arrives at the receiving location, it is received by the antenna (only a small portion of the power is r
integrated design environment provides system and circuit simulator, as well as circuit diagram capture, layout and verification capabilities, including many modules. EMDs : Full 3D Of Em Simulation, which can be used RF Circuit, MMIC ,PCB Module and signal integrity analysis, suitable for connectors, structural components, connection lines, antennas and encapsulation analysis. Empro : RF and Microwave Components Electromagnetic Effect Analysis Platform IC Encapsulation,
points is in line with the communication distance of bridge equipment.
Can use the point to point Way direct transmission: a building to place a wireless network bridge, the top placement side directional antenna; B building also placed a bridge without a network, the top of a directional antenna. Wireless network bridge between the two places through the feeder and the local
the device has good compatibility and can improve the performance of the device. If there is a problem, it will not be caused by the product of different companies.
Ii. Typical Installation Problems of Wireless Networks
1. Because the installation location is not selected, you need to change the installation location afterwards.
Solution: when selecting the installation location, ensure that there should be sufficient visible space between the antennas, and then consider whether installation an
present, wireless routers in the indoor launch power generally does not exceed 20dBm. The higher the transmitting power of the wireless router, the higher the signal strength, but more than the specified range will cause large electromagnetic radiation and interference.
antenna gain: the greater the gain, the stronger the signal strength, at present, most of our routers antenna gain 3dBi.
interface, internal slots only PCMCIA interface length half, so the use of very easy to cause a miscarriage of error.
The Mini PCI interface is the most common built-in interface in the notebook, which is essentially a scaled-down version of the PCI interface, which is very rich in the type of network card. The main advantage is that the network card inside the notebook, easy to use and safe, not in need of use when not found. The disadvantage is that you need to reserve the
wireless route, it will also seriously affect the transmission of wireless signals.
6. Adjust the antenna Angle
During use, the antenna angle is also worth our attention. Through the adjustment of the antenna angle, we can think of the enhancement of the coverage intensity of wireless networks in some areas, enhances the stability and transmission rate of the sp
wireless network will also cause electromagnetic interference, so the placement of wireless routers should also try to stay away from these appliances.
Extended Antenna enhancement signal
Because the size of the antenna gain directly affects the signal emission intensity and the ability to receive, and some of the routers in the market are removable design, so the wireless router to replace a high gain
other signal channels more than two.
In addition, a lot of home appliances in the work of the wireless network will also cause electromagnetic interference, so the placement of wireless routers should also try to stay away from these appliances.
Third, extended antenna enhancement signal
Because the size of the antenna gain directly affects the signal emission intensity and the ability to receive, and
. Contactless IC Card In addition to the card contains IC card circuit, also contains the relevant RF transceiver circuit and antenna coil. IC card can receive the signal of reader and writer in a certain distance, and realize non-contact reading and writing.RF Identification Card
Radio Frequency identification card (RF card, RFID card), also known as contactless IC card (contactless Smart card) or contactless IC card, contactless card, inductio
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