Electromagnetic compatibility EMC (Electro Magnetic Compatibility) refers to the ability of a device or system meets the requirements to run does not produce electromagnetic interference can not tolerate any of its equipment environment in its electromagnetic environment. Therefore, EMC requirements include two aspects: on the one hand refers to the environment where electromagnetic interference generated by the device during normal operation should not exceed a certain limit; on the other hand refers to electromagnetic interference present in the environment where the appliance to have a certain degree of immunity that electromagnetic sensitivity.
Interference between the various electronic devices running mainly in electric conductivity, electromagnetic induction and electromagnetic radiation in three ways associated with each other and affect each other, equipment and personnel under certain operating conditions will cause interference effects and hazards. EMC rectification on specific areas of the article is actually a lot. Terry detection (SKYLABS) also compiled a special six-step predecessors idea to do EMC rectification of reference for colleagues to learn.
EMC rectification six steps as follows: Step lookup confirmation radiation, a second step filter, absorbing the third step, the fourth step grounded shield fifth step, a sixth step an energy dispersion method. Specific ideas as shown below:
The first step : Find a radiation source confirmation has exclusion method, frequency search spectrum analyzer method, the natural frequency of the element analysis. With the exclusion pull line method of zoning exclusion, low voltage low current human touch method, the shield exclusion area. Element analysis refers to the natural frequency of the fixed frequency and its harmonic frequency analysis of the typology of some elements, such as the operating frequency of the crystal element and the like DDR are fixed.
Step Two : generally divided into filter capacitor filter, RC filter and LC filter and the like;
The third step : The method of absorbing electromagnetic waves with a series circuit beads method, magnetic method and worn around the absorbing material paste method. Pay special attention to the use of electromagnetic wave absorption methods: excessive radiation frequency electromagnetic waves must be absorbed by the absorber in the frequency range used, or cause the absorbing process will fail.
Step Four : ground method is generally divided into single-point ground method and multi-point ground method.
Step Five : Shielding shield generally applied method of shielding, the shielding housing and PCB trace layout method Shielding.
Step Six : an energy dispersion method refers to the control software of some analyte of energy concentration may show a wide frequency band of the bandwidth to achieve frequency hopping and band energy dispersion and the use of frequency hopping spread spectrum technology to a single point at the additional frequency the energy is reduced, that is, play a single point frequency electromagnetic wave radiation intensity decreases efficacy. Therefore the method of frequency shaped waveform spikes excessive radiation will play a significant effect on the shape of the envelope waveform frequency excessive radiation will not achieve significant effects.
The EMC rectification six-step method is more suitable for rectification common electronic devices. But six methods above, although in fact Terry Jun think they help to improve the rectification efficiency EMC radiation, saving cycle quickly through the EMC testing, but it is not a program to solve the fundamental problem of EMC, EMC problems or in the best design end to be considered, rather than to emergency afterwards with some "besieged" the program.