Smart electronic products are related products based on electric energy, mainly including watches, smart phoness, telephoness, televisions, video recorders (VCDs, svcds, DVDs), video recorders, video recorders, radioses, tape recorders, combination speakers, CD players, computers, game players, mobiles communication products, etc. Because the early products were mainly based on electronic tubes, they were named electronic products.

Chinese name electronic product foreign name electronic product Pinyin di à N Z ǐ  ch ǎ n p ǐ The development status of n-class ceramic capacitors and sheet inductors is developing rapidly, and the renewal speed is fast. Special categories are consumption and production.

Development history

Electronic technology is an emerging technology developed in Europe, the United States and other western countries at the end of the 19th century and the beginning of the 20th century. It was first invented by American Morse in 1837, American Alexander Bell in 1875 and British physicist Fleming in 1902. Electronic products developed most rapidly and widely in the 20th century, and became an important symbol of the development of modern science and technology.

The first generation of electronic products took electronic tubes as the core. In the late 1940s, the first semiconductor triode was born in the world. It was quickly applied by various countries and replaced the electron tube in a large range because of its small size, light weight, power saving and long service life. In the late 1950s, the first integrated circuit appeared in the world. It integrated many electronic components such as transistors on a silicon chip, making electronic products smaller. Integrated circuits have developed rapidly from small-scale integrated circuits to large-scale integrated circuits and very large-scale integrated circuits, so that electronic products develop in the direction of high efficiency, low consumption, high precision, high stability and intelligence.

Since the four stages of the development of electronic computer can fully explain the characteristics of the four stages of the development of electronic technology, the following will explain the characteristics of the four stages of the development of electronic technology from the four times of the development of electronic computer.

computer

First computer

The world's first electronic computer was successfully developed by the United States in 1946, named ENIAC (Electronic Numerical Integrator and calculator). This computer uses 18800 electronic tubes, covers an area of 170 square meters, weighs 30 tons, consumes 140 kW of electricity and costs more than 400000 US dollars. It is an expensive "behemoth" that consumes electricity. Because it uses electronic circuits to perform arithmetic operation, logic operation and store information, the operation speed is greatly improved. ENIAC can perform 5000 addition and subtraction operations per second, reducing the time for calculating a trajectory to 30 seconds. At first, it was specially used for trajectory calculation, and then after many improvements, it became a general-purpose electronic computer that can carry out various scientific calculations. ENIAC has been in service for nine years since it was put into use in February 1946 and finally cut off the power supply in October 1955.

Although ENIAC has many weaknesses, it is still an immortal milestone in the development history of human computing tools. Its success opens up an extremely broad possibility to improve the operation speed. Its appearance indicates the arrival of the electronic computer age. Since then, computers have developed by leaps and bounds on the road of liberating human intelligence. Compared with the steam engine in the first industrial revolution, the role of electronic computers in human society is better.

In the short 40 years since ENIAC came out, the development of electronic computers has been extremely rapid. So far, it has developed into the following four generations:

The first generation (1946-1957) is an electronic computer. Its basic electronic component is an electronic tube. The internal memory adopts mercury delay line, and the external memory mainly adopts magnetic drum, paper tape, card, magnetic tape, etc. Due to the limitation of electronic technology at that time, the operation speed was only thousands to tens of thousands of basic operations per second, and the memory capacity was only thousands of words. The program language is at the lowest stage, which is mainly programmed by binary machine language, and the later stage is programmed by assembly language. Therefore, the first generation computer has the advantages of large volume, high power consumption, low speed, high cost and inconvenient use; It is mainly limited to scientific calculation by some military and scientific research departments.

The second generation (1958 ~ 1970) is transistor computer. In 1948, Bell Laboratories invented the transistor. Ten years later, the transistor replaced the electronic tube in the computer and gave birth to the transistor computer. The basic electronic component of a transistor computer is a transistor. The internal memory uses a magnetic core memory made of a large number of magnetic materials. Compared with the first generation of electronic tube computer, transistor computer has the advantages of small volume, less power consumption, low cost, strong logic function, convenient use and high reliability.

The third generation (1963 ~ 1970) is integrated circuit computer. With the development of semiconductor technology, Texas company made the first semiconductor integrated circuit in the summer of 1958. Integrated circuit is a logic circuit composed of dozens or hundreds of electronic components on a substrate of several square millimeters. The basic electronic components of the third generation integrated circuit computer are small-scale integrated circuits and medium-scale integrated circuits. The magnetic core memory has been further developed, and the semiconductor memory with better performance has been adopted, and the operation speed has been increased to hundreds of thousands of basic operations per second. Due to the use of integrated circuits, all aspects of the performance of the third generation computer have been greatly improved: the volume has been reduced, the price has been reduced, the function has been enhanced, and the reliability has been greatly improved.

The fourth generation (1971 ~ recently) is large-scale integrated circuit computer. With the emergence of large-scale integrated circuits and very large-scale integrated circuits that integrate thousands or even tens of thousands of electronic components, the development of electronic computers has entered the fourth generation. The basic components of the fourth generation computer are large-scale integrated circuits, or even very large-scale integrated circuits. The highly integrated semiconductor memory replaces the magnetic core memory, and the operation speed can reach millions or even hundreds of millions of basic operations per second.

Competitive situation

The market size and Prospect of educational electronics industry have always been the focus of attention in the industry. Over the past few years, educational electronic industries such as electronic dictionary and PDA, which are generally considered to have a market scale of only a few billion, have attracted more consumers with the renewal of technology and the advent of the digital age, and the market scale has expanded to about 20 billion. There are 500 million people in China who need to learn English. Taking the purchase rate of 5% as an example, the sales volume will reach 25 million units. Based on the average price of 800 yuan per unit (the average price of electronic dictionaries and digital learning machines), the market scale will reach 20 billion. The education electronics industry is developing rapidly. Take the sales of Noah's boat as an example. In 2004, the sales of Noah's boat soared from 110000 units in 2000 to 2 million units. From another perspective, the data show that in the large English industry, the sales of books, tapes, VCDs and other audio-visual products are about 35 billion a year, and English training can also create 12 billion "brilliant achievements" every year. Since 2004, educational electronic products have gradually replaced the functions of books, audio-visual materials and training through technological upgrading, and began to carve up the cake of traditional industries.

Consumer electronic products have different connotations in countries with different development levels, and have different connotations in different development stages of the same country. Consumer electronic products in China refer to audio and video products used for individuals and families related to radio, television and communication, mainly including television, video disc player (VCD, SVCD, DVD), video recorder, video recorder, radio Tape recorders, music centers, CD players, computers, game consoles, mobiles communication products, etc. In some developed countries, telephones, personal computer, home office equipment, home electronic health care equipment and automotive electronic products are also classified as consumer electronic products. With the development of technology and the emergence of new products and applications, digital cameras, mobiles phoness, PDAs and other products are also becoming emerging consumer electronic products. Since the late 1990s, the information appliance, which integrates the three fields of computer, information and communication and consumer electronics, has been widely used in family life. It has the functions of audio-visual, information processing and two-way network communication. It is composed of embedded processor, relevant supporting hardware (such as display card, storage medium, IC card or credit card reading equipment) Embedded operating system and application layer software package. Broadly speaking, information appliances include all home appliances that can exchange information through network systems, such as PC, set-top box, HPC, DVD, super VCD, wireless data communication equipment, video game equipment, WebTV, etc. Audio, video and communication equipment are the main components of information appliances. In the long run, refrigerators, washing machines and microwave ovens will also develop into information appliances and form an integral part of intelligent appliances.

Domestic status

The operation monitoring and Coordination Bureau of the Ministry of industry and information technology learned that from January to November 2012, the total import and export of China's electronic information products amounted to US $1068.5 billion, a year-on-year increase of 4.1%, 0.8 percentage points higher than that from January to October. Among them, the export was 627.3 billion US dollars, a year-on-year increase of 4.5%, 0.6 percentage points higher than that from January to October, accounting for 33.9% of China's foreign trade export; Imports reached US $441.2 billion, a year-on-year increase of 3.5%, 1.0 percentage points higher than that from January to October, accounting for 26.7% of China's foreign trade imports. In November, the export of electronic information products reached US $67.6 billion, and the monthly export volume reached a new high of the whole year, an increase of 9.2%; Imports reached 48.8 billion US dollars, an increase of 4.3%.

Shengkete's exports of communication equipment, radio and television equipment and electronic devices have increased significantly. From January to November 2012, the export volume of communication equipment, radio and television equipment and electronic devices reached US $133.1 billion, US $10.6 billion and US $78.3 billion respectively, with a year-on-year increase of 14.0%, 13.9% and 13.5%, which is the main force driving the export growth of electronic information products; The export growth of computers, electronic components and electronic instruments and equipment was flat, with the export volume of US $214.6 billion, US $82.4 billion and US $25.1 billion, an increase of 2.7%, 2.9% and 3.7%. The export of home appliances and electronic materials showed a downward trend. From January to November 2012, the export of home appliances was US $78.3 billion, a year-on-year decrease of 9.3%.

Educational Electronics

Educational electronic products are referred to as ELP (e-learning products). Educational electronic products are e-learning tools that use electronic and multimedia technology to change passive education into active learning. Broadly speaking, all electronic products related to education can be called educational electronic products. In China, educational electronic products mainly refer to repeaters, point readers, electronic dictionaries (student handheld computers), student computers, game consoles, etc. At present, people are mainly familiar with electronic dictionaries and student computers.

Development status

After mobiles phoness, dairy products and automotive lubricants, the education electronics industry will become another fast-growing industry in China to quickly build national brands and expand market capacity through communication. The rapid rise and development of this industry has attracted the attention of all sectors of society. As an emerging industry, how to jointly expand and do a good job in this market has become a hot topic of common concern and discussion in all sectors of society. However, it goes without saying that under the excessive speculation of some representative manufacturers, the industry has suffered from "dwarfism", which has not fully expanded, but has exposed signs of premature aging. In the marketing of Haojixing, e percent, Noah boat and other products, they all use the health care product method of "intimidation + inducement" to capture parents. Although they have made brilliant achievements in a short period of time, they also bury the hidden danger of market collapse. The sales volume of "Haojixing" has shown an obvious downward trend in some key cities, and the business risk is imminent. The learning machine industry is like the home appliance market a few years ago. It competes for advertising, compares concepts, kills prices and grabs terminals. It staged a vigorous hand-to-hand battle: old brands are crazy about advertising in order to seize the market, and new brands fish in troubled waters by low-cost and low-quality products. As consumers become more rational, it can be predicted that the focus of digital learning machine market competition will gradually return to more original product and service innovation. Therefore, all brands began to make more rational strategic adjustments, and first-line brands have set up entry barriers in order to clean up the market. When the learning machine industry develops to a certain extent, shuffling is a law and necessity. The whole industry is still in a mixed brand, good and bad, and there is an urgent need to clean up the portal. The learning machine industry will reshuffle. Those brands with weak strength and fishing in troubled waters are doomed to be eliminated.

Facing the rigid demand of students for learning aids, educational electronic products (ELP) have been constantly excavating and meeting the needs of students since its birth. It has gone through the "tape recorder era" (the first generation), "repeater era" (the second generation), "electronic dictionary era" (the third generation) and "video learning machine era" (the fourth generation). As tape recorders and low-capacity storage media gradually fade out of the public's sight, it is not difficult to find that every intergenerational change of audio-visual education products is deeply branded with the development of scientific and technological hardware. The student tablet computer represented by Taiqi, with its powerful human-computer interaction mode and multimedia learning mode, has both portability and practicability. It is favored by the consumer market. It has indisputably ended the era of traditional audio-visual education products, and educational electronic products have entered the fifth generation development period with tablet computer as the hardware carrier.

The first generation of educational electronic products

In the early 1980s, tape recorder, as a learning guidance tool, was widely used in educational learning, especially in language learning. It was called the first generation of educational electronic products.

The second generation of educational electronic products

In the early 1990s, the repeater was born. As a continuation of the first generation of educational electronic products, the repeater still has the main function of tutoring language learning.

The third generation of educational electronic products

In the mid-1990s, electronic dictionaries appeared on the market. The electronic dictionary was originally an electronic product with an independent display screen, which provides functions such as personal information management, Chinese-English dictionary, Chinese-English translation and so on. In the late 1990s, electronic dictionary was not only a counseling tool for language learning, but also included curriculum knowledge points and formulas at different learning stages, and increased extracurricular interesting knowledge. At the beginning of the 21st century, with the popularity of the Internet, the content of electronic dictionaries can be enriched and updated through network download.

The fourth generation of educational electronic products in the early 21st century, portable learning machines officially listed. In the era of the third generation of educational electronic products, the learning machine has taken shape, but at that time, it mainly used the TV screen for output and display, which has become a major trend. With the development of technology, the learning machine not only has the portable appearance of electronic dictionary, but also further enhances the product function and supports different learning forms and diversified subjects. Powerful, some have open operating system, support capacity expansion, player and other functions.

In 2005, learning machines paid more attention to the application of learning resources and teaching strategies than other mobiles terminals. The functions of classroom synchronous guidance, general subject auxiliary learning function, multi-national language learning, standard professional dictionary and free expansion of memory have begun to become the mainstream competitive means of learning machine. With the popularity of the network, more and more learning machine products are fully compatible with various modes such as network learning, situational learning, portable foreign teachers, word associative memory, online library, as well as the free expansion function of large memory and SD / MMC card memory.

The fifth generation of educational electronic products

In 2011, the fifth generation educational electronic product - student tablet computer was listed. The core of the fifth generation products

Technology 3D interactive incentive learning platform has epoch-making significance. As an exclusive 3D interactive incentive learning platform, Taiqi pad makes a strict distinction between the fifth generation e-education products and the products in the later fourth generation. Experts from all walks of life believe that the products in the later stage of the fourth generation are only an extension of the learning machine. In other words, it is a learning machine that can surf the Internet.

The epoch-making significance of the fifth generation lies in the 3D interactive incentive learning platform, so that children no longer use educational electronic products as a teaching aid tool.

Industry standard

The society has gradually changed from the original steam age and electrical age to the information age. Due to the needs of technology and product functions, some electronic information products contain toxic and harmful substances or elements such as lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls and polybrominated diphenyl ethers. The products of these substances have a serious impact on human health and the environment in the process of disassembly and disposal after use and waste. These impacts need to further standardize the identification of electronic information products, promote electronic information products to meet environmental protection requirements, and jointly safeguard the legitimate rights and interests of producers, operators and consumers!

USB flash disk industry standard

According to China information industry network, the draft for approval of the general specification for information technology mobiles storage flash disk formulated by China is finally finalized and can be released and implemented after being approved by the National Standardization Management Committee. At the same time, other general specifications in the standard system and the smart memory card technical standards still under discussion are still under further study. The introduction of the standard will help the USB flash disk industry develop healthily in the direction of standardization. The long-standing mixed situation of the USB flash disk industry may come to an end, which will make it possible to protect the interests of USB flash disk consumers. The discussion of USB flash disk industry standard began in early 2004. At that time, there were hundreds of brands in the domestic U-disk industry, among which many U-disk factories used low-quality electronic components and low-quality chips to manufacture U-disks, that is, the so-called "screwdriver factory". Due to the poor quality of the products produced by these USB flash disk factories, they have caused a very adverse impact on the market and further damaged the reputation of the USB flash disk industry. However, due to the lack of a unified industry standard, the relevant national departments can not punish it, and the "screwdriver U disk factory" continues to this day.

In this context, in March 2004, 21 units including China electronics chamber of Commerce, Longke Technology (holder of flash disk invention patent), Putian Information Technology Research Institute, Founder Technology, Silicon Valley "U disk flash memory manufacturer", Huaqi Information, TCL and others established a flash disk standard working group to begin research on mobiles memory related technologies Conduct research on quality and production standards and formulate revision plans to ensure the healthy development of the industry and protect the interests of consumers. The operation monitoring and Coordination Bureau of the Ministry of industry and information technology learned that from January to November 2012, the total import and export of China's electronic information products amounted to US $1068.5 billion, a year-on-year increase of 4.1%, 0.8 percentage points higher than that from January to October.

It is understood that the general specification for information technology mobiles storage flash disk, which has been submitted for approval, includes seven parts: scope, normative references, term definitions and test methods, and has made corresponding provisions on the basic functions, reading and writing speed and other performance requirements of USB flash disk.

Once the standard is implemented, those substandard USB flash disks using substandard electronic components, substandard chips and outdated low-speed control chips will be judged as substandard products, and these products will be prohibited from being sold on the market, which is also a fundamental elimination for those USB flash disk factories that manufacture substandard USB flash disks. This is a sign that the USB flash disk industry has moved from maturity to standardization. The promulgation and effective implementation of the standard is conducive to the sustainable, healthy and stable development of the USB flash disk market and a strong guarantee for the rights and interests of consumers.

It is reported that, according to the general process, the standard formulation process should go through several stages, such as draft, submission for approval, submission for approval and release. In November 2004, the working group began to draft the mobiles storage standard. On April 25, 2006, the working group sorted out the draft of the standard for review. The draft for approval has been finalized and entered the stage of submission for approval. At the same time, the working group has cooperated with China Institute of electronic technology standardization to complete the testing platform of this standard, so as to facilitate the third-party certification after the implementation of the standard and prepare for its implementation.

In addition, the USB flash disk general specification is a part of the whole storage standard system. The general specifications for memory cards, micro mobiles hard disks, MP3 and MP4 players have also been submitted for approval.

environment condition

In the process of storage, transportation and use, electronic products are often affected by various harmful effects of the surrounding environment, such as affecting the working performance, service reliability and service life of electronic products. Environmental factors affecting electronic products include: temperature, humidity, atmospheric pressure, solar radiation, rain, wind, ice and snow, dust and sand dust, salt fog, corrosive gas, mold, insects and other harmful animals, vibration, impact, earthquake, collision, centrifugal acceleration, sound vibration, swing, electromagnetic interference and lightning.

The research on environmental factors mainly solves two basic problems:

① How to obtain objective data of these environmental factors;

② How to process this data. The data of objective environmental factors can usually be obtained partly from meteorological and environmental protection departments, but more must be obtained through actual measurement. In order to make the measured data reliable and typical, in addition to a perfect investigation and test scheme, there must also be continuous, rapid and multi-point recording instruments. If the objective environmental data obtained has a long enough recording time, it can be statistically analyzed according to the occurrence frequency. For products requiring special reliability, the extreme value of objective environmental data or even the extreme value of statistical inference can be taken to ensure that the product is safe in use. For products requiring high reliability, the occurrence probability of objective environmental data can be taken as 1%. For products with general requirements, the occurrence probability of objective environment can be 5%, or even 10%. If the recording time of objective environmental data is not long enough, we should use the knowledge of mathematical statistics to process it. For example, the measured data of microclimate can be extended by correlation method to calculate the possible data in history; As another example, for the measured survey data of mechanical vibration, the envelope method, power spectrum analysis method or time series modeling method can be used to calculate the possibility of various probability values, and then the required data can be obtained according to the reliability requirements of the product.

The test severity levels commonly used for climatic and environmental conditions are:

① Temperature (℃): - 80, - 65, - 55, - 40, - 25, - 15, - 5, + 5, + 15, + 20, + 25, + 30, + 40, + 55, + 60, + 70, + 85, + 100, + 125, + 155, + 200;

② Temperature change rate (℃ / min): 0.1, 0.5, 1, 3, 5, temperature change rate (℃ / s): 1, 5;

③ Relative humidity (%): 10, 50, 75, 90;

④ Pressure (mbar): 300000, 50000, 10000, 5000, 2000, 1300, 1060, 840, 700, 530, 300, 200;

⑤ Pressure change rate (mbar / s): 1, 10;

⑥ Relative moving speed of surrounding medium (water, air, etc.) and product (M / s): 0.5, 1, 3, 5, 10, 30, 50;

⑦ Rainfall (mm / s): 0.3, 1, 2, 3, 6, 15.

Biological environmental conditions include molds, insects and animals.

① Mold: the most harmful strains to electronic products are Aspergillus flavus, Aspergillus niger, Aspergillus terreus, budding pullulans, Paecilomyces vannamei, Penicillium cordiformis, Penicillium ochraceus, Trichoderma viride, Aspergillus heterophyllus, Chaetomium globosum, etc. The optimum germination temperature of these fungi is 20 ~ 30 ℃, and the corresponding relative humidity is 80% ~ 90%.

② Insects: termites, bark beetles, wood bees, cockroaches, etc. are the most harmful insects to electronic products, especially in tropical areas.

③ Animals: the animals most harmful to electronic products are rats, snakes and birds, especially in tropical areas.

Under the environmental conditions of mechanically active substances, sand blowing will occur in hot desert area, sandy coastal area and arid inland area. Under normal circumstances, the diameter of sand particles is 0.01 ~ 0.1mm, and the average diameter of sand particles in sandy desert area is 0.18 ~ 0.30mm. Dust blowing mainly occurs in Industrial Soot area and arid wind area. The average diameter of dust is 0.0001 ~ 0.01 mm. In the extreme case of much dust, the concentration can reach 6 × 10-9 g / cm3. Sand blowing and dust blowing mostly occur under the weather conditions of high temperature and low relative humidity. The commonly used test severity level is:

① Sand (g / cm3): 0.01, 0.03, 0.1, 0.3, 1, 3, 10;

② Dust (mg / m2 · h): 1, 3, 10, 30.

Environmental conditions of chemically active substances

① Salt fog: chloride liquid particles suspended in the air are called salt fog. Salt fog can go deep from the sea to 30 ~ 50 kilometers along the coast with the wind. The sedimentation on ships and islands can reach more than 5 ml / cm2 per day. The commonly used severity levels for the test (ml / cm2 · h) are: 1, 3, 5 and 10.

② Ozone: ozone is harmful to electronic products. The commonly used test severity levels (mg / m3) are 0.01, 0.03, 0.1, 0.3, 1, 3, 10 and 30.

③ Sulfur dioxide, hydrogen sulfide, ammonia, nitrogen and oxides: in the chemical industry sector, including production sites such as mines, chemical fertilizers, medicine and rubber, the air contains many corrosive gases, the main components of which are sulfur dioxide, hydrogen sulfide, ammonia and nitrogen oxides. These substances can form acidic and alkaline gases under humid conditions and damage all kinds of electronic products. The commonly used severity levels (mg / m3) in the test are 0.01, 0.03, 0.1, 0.3, 1, 3, 10, 30, 100 and 300.

Mechanical environmental conditions

① Falling: electronic products will fall due to carelessness during use and transportation. Generally, the severity levels (m) used for the test are 0.025, 0.050, 0.1, 0.25, 0.5, 10, 2.5, 5.0 and 10.0.

② Rocking: electronic products should bear the rocking motion of the ship during loading, use and transportation. Generally, the severity level (degrees / 6 seconds) used for the test is ± 5, ± 10, ± 25 and 45.

③ Constant acceleration: electronic products will undergo constant acceleration force in use and transportation. The commonly used test severity levels (M / S2) are: 20, 50, 100, 200, 500, 1000.

④ Vibration: the actual vibration conditions are complex, which may be simple sinusoidal vibration, complex random vibration, or even sinusoidal vibration plus random vibration.

⑤ Impact and collision: electronic products are often damaged by collision during transportation and use.

⑥ Noise: in high noise places such as weaving workshop, large steam turbine generator workshop and ship main engine compartment, the noise can reach 90 ~ 100 dB. When the jet engine works and the rocket is launched, the noise can reach 140 ~ 160 dB. The commonly used test severity levels (DB) are 140 and 160.

Electrical environmental conditions

① Lightning: thunderstorms are frequent in hot and humid areas. For example, the annual thunderstorm day (i.e. the number of days when thunder or thunderstorm occurs) in Bogor City, Java, Indonesia is 322 days. The principle for determining the time of T1 and T2 in the lightning pulse waveform generated by lightning is: the electronic equipment connected with the open line should be tested with the waveform of T1 = 4 microseconds and T2 = 300 microseconds; For electronic equipment connected with cables, T1 = 10 microseconds and T2 = 700 microseconds should be used; For electronic equipment connected with steel rail or similar conductor, T1 = 10 microseconds and T2 = 200 microseconds should be used; T1 = 1.2 microseconds and T2 = 50 microseconds should be used to simulate the counterattack against direct lightning. During the test, the commonly used voltage levels (kV) are: 1.5, 4, 5 and 6.5.

② The electromagnetic field of electrical equipment and the electromagnetic field generated by the ignition system of motor vehicles are measured at a distance of 10m from the interference source, with a frequency range of 40 dB (microvolt / M). The interference voltage generated by electrical appliances with motors is 66 dB (microvolt) in the range of 0.15 ~ 30 MHz; 55 dB (microvolt) in the range of 30 ~ 300 MHz. When the motor power increases, the interference voltage will also increase. For the electromagnetic field generated by high-frequency equipment, the field strength in the range of 0.15 ~ 1000 MHz measured 100 meters away from the interference source is 34 ~ 54 dB (microvolt / M).

reliability

With the increasing expansion of the application field of electronic technology, the reliability of electronic products puzzles maintenance personnel more and more. There are many problems affecting the reliability of electronic products, among which noise is the most important aspect. The so-called noise is the general name of interference signals that cause adverse effects on people or equipment. For example, the sound and image signals that cause people's physical and mental unhappiness, and the signals of the wrong operation of the machine, etc.

The attitude towards noise is the same as that towards fire. Sufficient measures should be taken in advance, otherwise it will cost both money and time. In the design or trial production of electronic products, the working conditions to prevent noise should have a rich tolerance range, which is the premise to ensure the reliability of the equipment.

1. Working conditions for reliability of electronic products

As the insulation materials of electronic products are affected by moisture, the insulation degree will be reduced, resulting in leakage current and noise. Therefore, the place where electronic products are stored or placed must be dry, have sufficient moisture-proof measures, and avoid placing them at the foot of high humidity or concrete wall.

Due to the electrostatic effect of electronic products, it is easy to absorb dust, resulting in the reduction of the insulation of electronic components and the increase of temperature. Therefore, electronic products should be cleaned and dedusted frequently.

The metal part of electronic components will be oxidized, rusted and change the resistance in contact with air, resulting in poor contact and noise. The metal or welding parts that are afraid of rust shall be painted with enamel to protect them. In addition, the acidic flux used in welding will still corrode the metal part of electronic components and cause poor contact if it is not removed after use. Adequate anti-corrosion measures shall be taken in places with corrosive gas.

The environment where the equipment is located is easy to generate noise due to some vibration or impact. Anti vibration and impact measures shall be taken for equipment component installation or wiring fixation. Avoid careless and rough operation. Do not collide and handle with care during handling.

2. Maintenance of electronic product noise

For the maintenance of electronic product noise, first judge whether the fault is maintenance or improvement according to the noise or abnormal working state of electronic product, and then find out the cause according to the fault. Once the original normal electronic products produce noise, it is an obvious fault and needs to be repaired. However, the electronic products put into use have noise at the beginning, which is related to the environment, service conditions and equipment performance. This is not within the scope of maintenance, but an obvious improvement problem. Maintenance is to find out the cause of noise. Even if the task is completed, it is relatively simple. The improvement is to completely solve the family problem of noise from head to toe, which is the key problem. There are many reasons for the noise of electronic products. Some noise is caused by only one reason, while others are caused by a mixture of various reasons. According to the noise source of electronic products, the noise can be divided into internal noise and external noise.