Classification of radio frequency technology:
Automatic identification technology
Automatic equipment identification technology is a new technology that is developing rapidly in the international arena, the English name is Automatic Equipment Identification, or AEI for short. The basic idea of this technology is to use some advanced technical means to achieve the following The basic idea of this technology is to use some advanced technical means to realize the people of all kinds of objects or equipment (personnel, goods) in different states (mobile, static or harsh environment) under the automatic identification and management.
At present, the most widely used automatic identification technology can be roughly divided into two aspects: optical technology and radio technology. One of the optical technology in the general application of the products are: bar code and camera two categories. These two types of products have been widely used in people's daily life, and has been known to people. For example, barcode is used for commodity management, and camera is used to capture illegal vehicles.
Radio frequency recognition technology
Radio frequency recognition technology can be divided into two categories of low frequency system and high frequency system according to the frequency difference; according to the electronic label is equipped with a battery for its power supply, can be divided into two categories of active and passive systems; from the electronic label to save the information injected into the way can be divided into the integrated circuit curing type, on-site wired rewrite type and on-site wireless Rewrite type three categories; According to read the electronic label data technology realization means, can be divided into broadcasting emission type, frequency multiplication type and reflection modulation type three categories.
1. Low frequency system generally refers to its working frequency is less than 30MHz, the typical working frequency has: 125KHz, 225KHz, 13.56MHz, etc., these frequency points apply the radio frequency recognition system generally have the corresponding international standard to support. The basic characteristics of the electronic tag is the lower cost, the amount of data saved in the tag is less, reading distance is shorter (passive case, the typical reading distance of 10cm) electronic tag shape is diverse (card, ring, button, pen), reading antenna directionality is not strong, and so on.
2. High-frequency system generally refers to its operating frequency greater than 400MHz, the typical working frequency band: 915MHz, 2450MHz, 5800MHz and so on. High-frequency system in these frequency bands also have many international standards to support. The basic characteristics of the high-frequency system are electronic tags and reader costs are higher, the tag to save a larger amount of data, reading distance is farther (up to a few meters to a dozen meters), to adapt to high-speed movement of the object performance is good, the shape of the general card-like, read the antenna and the tag antenna have a strong directionality.
3. Active tags are equipped with batteries, generally have a longer reading distance, the shortcomings of the battery life is limited (3 ~ 10 years); passive tags without batteries, it receives the reader (readout device) issued by the microwave signals, part of the microwave energy into DC power for their own work, generally maintenance-free. Compared with the active system, the passive system in the reading distance and adapt to the object movement speed is slightly limited ......
Question 2: What is the meaning of radio frequency Radio waves need to be emitted, must be high frequency to a certain extent, such as the current GSM 900MHZ and 1800MHZ. The frequency of the sound is very low, only 20HZ-20KHZ, the frequency of the signal can not be directly emitted, it must be modulated to a high frequency is also that is the radio frequency to be able to emit, which is the meaning of the RF.
In order to achieve good communication between the cell phone and the base station, the radio frequency emitted by the cell phone must be strong enough to work, when the cell phone and the base station distance is close, you can use less power to maintain communication, when the cell phone and the base station distance is very far, the cell phone must increase its own transmit power in order to maintain a good level of communication. Therefore, the power of the RF in the cell phone is automatically adjustable.
As today's cell phones in order to look small, many of the antenna integrated inside the phone, which has a certain impact on the RF emission, in order to achieve good results, the phone had to further increase the RF power to maintain normal operation, sometimes, this power exceeds the value of the national standard, it will have a certain impact on the human body.
Receiver characteristics are also important for the entire cell phone system. Poor receiver characteristics can cause the user to hear very low quality sound signals, or even cause the user to lose base station information and cause termination of the call. Poor receiver sensitivity is often caused by internal noise and spurious signals emitted by the transmitter feeding back into the receiver. Therefore, the CTIA standard requires that receiver sensitivity be measured at the maximum transmitter power.
Question 3: What does RF mean? RF stands for Radio Frequency. In the theory of electronics, the current flows through the conductor, the conductor around the formation of a magnetic field; alternating current through the conductor, the conductor around the formation of alternating electromagnetic fields, known as electromagnetic waves. When the frequency of electromagnetic wave is lower than 100khz, the electromagnetic wave will be absorbed by the ground and can not form an effective transmission, but when the frequency of electromagnetic wave is higher than 100khz, the electromagnetic wave can be propagated in the air.RF refers to the high-frequency tactile magnetic wave which has the ability to be transmitted over long distances, and the RF technology has been widely used in the field of wireless communication.
Question 4: What is the radio frequency line Radio frequency, that is, can be directly through the transmitting device to become the frequency of radio waves. The so-called radio frequency line, is able to transmit this kind of communication signal cable! Generally have (soft, hard) coaxial bile cable, waveguide, etc.
Question 5: What is the RF service in the cell phone ah GSM Global System for Mobile Communications , the second generation of digital mobile communication systems.
GPRS established on the GSM network, can provide cell phone Internet, MMS and other new services of a network.
WIFI A technology that allows terminals such as personal computers and handheld devices (e.g., PDAs, cell phones) to connect to each other wirelessly.
RF Radio Frequency (RF) technology, a technology that allows interactive communication through inductive means.
Cell phone amplifier A functional module inside the main board of a cell phone circuit that is used to put the received wireless signals.
Question 6: What is the meaning of cosmetic RF? Cosmetic RF generally refers to radio frequency beauty.
Radiofrequency cosmetic positioning tissue heating, prompting subcutaneous collagen contraction and tightening, while the skin surface cooling measures, the dermis is heated while the epidermis to maintain a normal temperature, this time will produce two reactions: one is the dermis of the skin thicker, wrinkles with shallow or disappear; two is the form of subcutaneous collagen remodeling, the production of new collagen, the skin in the Lido after a treatment to become tighter.
Question 7: What is the difference between high-frequency and radio frequency "High-frequency" refers to a range of frequencies
"Radio Frequency" refers to the radio frequency circuitry generated by a specific frequency of the modulation wave.
Question 8: RF is high-frequency RF "shot" is what it means? Indicates that the electromagnetic frequency can be radiated into space, the frequency range from 300KHz to 300GHz. Radio frequency is short for RF radio frequency is radio frequency current, it is a high-frequency alternating electromagnetic waves. The alternating current that changes less than 1,000 times per second is called low-frequency current, and the one that changes more than 10,000 times per second is called high-frequency current, and radio frequency is such a high-frequency current. High frequency (greater than 10K); radio frequency (300K-300G) is the higher frequency band of high frequency; microwave band (300M-300G) is again the higher frequency band of radio frequency.
Question 9: What is the RF front-end equipment? RF front-end refers to the communication system, the antenna and the intermediate frequency (or baseband) between the part of the circuit. In this segment signals are transmitted in RF form. For wireless receivers, the RF front-end typically consists of: amplifiers, filters, inverters, and some RF connectivity and matching circuitry.
Question 10: What is a radio frequency card A radio frequency card (RF card for short) is a card that transmits data wirelessly on a set of terrier circuits, which has unique advantages such as data processing and security authentication features.