Question 2: What do you mean by signal strength? Cell phone signal strength is the strength of cell phone signal, which is expressed as follows:
The unit of the number displayed on the mobile phone is dBm (you can use ALT+NMLL to let the mobile phone display the currently received signal value). This value is negative, indicating that the mobile phone will display, for example, -67(dBm), indicating that the signal is very strong.
China Mobile's specifications stipulate that the receiving level of mobile phones is >: = (-90dbm in the city; When the country takes -94dBm), it meets the coverage requirements, that is, the wireless signal strength here meets the coverage requirements. -67dBm is more than 20 dB stronger than -90dBm, so its call success rate and voice quality during the call will be much better (including the Internet access speed of EDGE/GPRS, of course).
So the bigger the value, the better the signal, because it is negative, and you will always be negative when you hold it. If you are interested, there is an antenna of a wireless base station nearby, and you can also put your mobile phone as close as possible to the antenna panel, which will be more and more valuable; If the mobile phone is next to the antenna panel, it may be close to 0 (0 can't be reached, and the 0 here doesn't mean that the mobile phone has no signal).
DB and dBm are units of power gain, and the differences are as follows:
DB is a numerical value representing a relative value, and it is a pure ratio, which only represents the relative size relationship between two quantities, and there is no unit. When considering how much dB the power of A is larger or smaller than that of B, according to this calculation formula: 10log (A power /B power), if the voltage ratio between them is used to calculate, 20log (A voltage /B voltage) will be taken.
[Example] The power of A is twice that of B, so 10lg (A power /B power) = 10lg2=3dB. In other words, the power of A is 3 dB greater than that of B. On the contrary, if the power of A is half that of B, the power of A is 3 dB less than that of B. ..
DBm is a numerical value representing the absolute value of power (which can also be considered as the ratio of 1mW power), and the calculation formula is: 10log (power value/1mw).
[Example] If the power p is 1mw, it will be 0 dBm after conversion to DBM.
[Example] For the power of 40W, the conversion value expressed in dBm should be:10log (40w/1MW) =10log (40000) =10log4+10log/kloc-.
In a word, dB is the ratio between two quantities, indicating the relative size between the two quantities, and dBm is the numerical value indicating the absolute size of power. In the calculation of dB and dBm, we should pay attention to the basic concepts. When one dBm is subtracted from another, the result is dB, for example, 30 dBm-0 DBM = 30 dB.
The relationship between signal strength and signal grid number display;
Engineers divide the number of signal units according to the value of acceptance level, and express more complex data intuitively in front of our eyes. Having said that, I can't help mentioning that many netizens say that some mobile phones have two signals in the same place, and some mobile phones have no signal. I believe everyone understands now. Of course, there are small differences in the classification of signal grids according to grade values, and there are also individual differences and grade acceptance differences between mobile phones.
Question 3: What do signal letters mean? The signal itself has the meaning of data and news. In ancient times, letters were transmitted by flying pigeons and books. Modern times give signals more data meaning.
Question 4: What does signal quality mean? The stronger the strength of digital signal, the stronger its anti-interference ability, such as snow and electromagnetic interference. Weak signals are easily interrupted, and the phenomenon is mosaic. As long as the signal reaches a certain intensity, the quality of video and audio signals will remain unchanged.
Your point of view is still in the analog age, and we have all digitized it.
Question 5: What do the Vpk and vrms of the signal source mean? Vpk: peak voltage
Vrms: Effective value of voltage
Question 6: What is the definition of signal source 1?
14 grounding body is defined as strong current, weak current, lighting, lightning protection, process, standby grounding, etc. And they are insulated from each other. In this case, no matter where the signal comes from, we define the signal source as: signal strength is 16dBmV(76dBuV), CTB is 65dB, and carrier-to-noise ratio is 50dB (according to national standards).
Source: Nanjing TV Studio Center, Radio and Television Technology, 2002, Wang Changsheng and Shen Baogen.
Abstract: Based on the positioning of TV technology design of Nanjing TV Station's studio center, this paper expounds the general requirements of TV technology for the studio center building and the construction of the studio center building according to the TV technology requirements, and emphatically introduces the 15 0 0 m2 multifunctional TV theater in the building, its professional characteristics and the construction of digital system engineering.
Definition 2:
Signal source refers to radio head, tuner, recording card holder, display card holder and other equipment. Microcomputer and auxiliary equipment complete signal extraction, digital-to-analog conversion, digital signal processing, digital-to-analog conversion and other functions.
Origin:' 98, entries of the first Tsinghua University Entrepreneurial Plan Grand Prix ... China Science and Technology Information 1998.
Name of business philosophy: ESR description of shopping mall service robot: ESR organically combines mobile robot with partial self-weight control and intelligent upper limb with shopping mall/hotel service function with communication and voice system to meet the advertising needs of shopping malls/hotels to attract customers with novelty. ESR is mainly aimed at large shopping malls and high-end hotels with purchasing power and demand, with broad market prospects. At the same time, ESR has competitive advantages such as low cost, high performance-to-price ratio, quick investment recovery, patent and technical and human resources advantages. The investment is 5-65.438+million yuan, and it is predicted that the product sales will exceed 65.438+0 billion yuan and the profit will exceed 20 million yuan in five years.
Definition 3:
The events that send out signals are called signal sources, which mainly include processes, kernels, interrupts and exceptions. Signal processing must be completed by the process that receives the signal, which is allowed to ignore the signal, block the signal, give the signal to the kernel for default processing, and process the signal by itself after receiving the signal.
From: Linux and ... Computer Engineering and Application, 2005, Wang, Wu Hua.
Abstract: For a multi-user and multi-task operating system, inter-process communication is very important, which is the basis of the orderly work of the whole system. Linux operating system provides a variety of IPC mechanisms, such as signals, pipes, semaphores, message queues, * * shared memory and sockets. Among them, signal is an indispensable IPC mechanism of the system and an inseparable part of the kernel, and other mechanisms are optional. Therefore, in-depth analysis and research on the signal communication mechanism of Linux system will be of great help to the development of application system. Starting with RedhatLinux9.0 (kernel 2.4.20-8), this paper focuses on analyzing the data structure and several key system functions, and gives an application example in combination with the whole signal communication process.
Definition 4:
The method of judging the fault of sensor and weighing instrument: unplug the signal line from the weighing instrument and connect it with special analog sensor (some are also called signal source). If the weighing instrument is stable at this time, it means that the instrument is good and the fault lies in the sensor.
From: the installation of electronic truck scale and the judgment of common faults 《 Shanghai Metrology Test 》 1997 Feng Wei.
Abstract: 1. Several problems that should be paid attention to when installing electronic truck scale With the development of electronic technology, the use of electronic truck scale is becoming more and more common. Due to improper installation of electronic truck scale, it often breaks down, which affects the use effect. In order to make good products have good performance, corresponding effective measures should be taken during installation. The following are several problems that must be paid attention to during the installation of electronic truck scale.
Definition 5:
Therefore, all instruments related to measurement >>
Question 7: What does it mean that the computer has no signal input? There are several possibilities:
1, the monitor is not plugged in, just plug it in.
2. If there is a problem with the signal connection between the monitor and the chassis, check whether the signal line is loose. If not, check whether the signal line is intact. If it is intact, check whether the video card output is normal.
3. The input signals of the monitor do not match. Some graphics cards can only output DVI format. If your monitor is set to VGA input gaze, there is no signal. Try to modify the input signal type in the monitor settings.
4. If the monitor itself fails, check whether the monitor is in good condition and whether there are internal problems.
Question 8: What do you mean when the signal changes to H+? H+ is a data signal pattern.
Also known as HSPA+, this is a 3G signal.
Question 9: What is signal H? Mobile phone network speed from slow to blocked is G. Question 10: What does the movie signal mean?
Signal (20 14)
Director: William? Eurobank
Screenwriter: Carlisle? Eubank/William? Eubank/David? Frigerio
Starring: Patrick Davidson/brenton? Thwaites/Olivia? Cook/Bo? Nap/Jeffrey? Grover/Lawrence? Fishburn/Lin? Ye Sha
Type: science fiction/thriller
Country of manufacture: USA
Language: English
Release date: 20 14-06- 13
Duration: 97 minutes
Also known as: paradox? Different? News (Taiwan Province)/Strange News
Brief introduction to the plot of the signal
Nick with a broken leg (brenton? Thwaites brenton thwaites) and his girlfriend Harry (Olivia? Cook olivia cooke and his good friend Jonah (Wu Bo? Neptune beau knapp is a long and bittersweet journey. Before that, he and Jonah, who is studying at MIT, have been tracking down a talented hacker who invaded the school website. After a period of hard work, they finally caught the trace of the hacker. The two men threatened to expose each other, but the other side seemed to be watching them. The journey continued, and as night fell, the three of them were going to live in an abandoned hut. Just then, there was a cry for help from Haley outside the house, and Nick was knocked down by someone else.
When he woke up again, he saw a strange man in a radiation suit (Lawrence? Fishburn laurence fishburne is talking to him. At this moment, he seems to be caught in a huge conspiracy about alien creatures, and this nightmare will never end. ...