The optimal solution to ensure the excellent certification quality of EMI testing 1 The Optimal Solution to Ensure the Excellent Certification Quality of EMI Testing www.instek.com GOOD WILL INSTRUMENT CO., LTD. The optimal solution to ensure the excellent certification quality of EMI testing 2 3GHz Spectrum Analyzers have become an important With the advancement of high-tech development, the tool to characterize the EMI testing issues of EMI come out and diffuse over the broad In terms of propagating path, there classify into electronic applications. The increasing operating speed conducted EMI and radiated EMI. The conducted EMI and integrated density semiconductor devices are results from that the radiated signal adheres along the enlarging the higher noise level than before so that many power line and hard to detect and recognize. Therefore, it of the distortion sources of signal become hard to detect is necessary to build the causes and effects methodology and recognize. Therefore, it is necessary to build the by way of the correct measurement to maintain the causes and effects methodology by way of the correct electromagnetic compatibility, to target the measurement to maintain the electromagnetic electromagnetic interference, and to detect radio compatibility, to target the electromagnetic interference, frequency interference. With the state-of-art design and to detect radio frequency interference. among various testing devices, outstanding low noise floor level of -117dBm at 1 GHz of the 3GHz spectrum With the state-of-art design among various testing analyzer performs extreme sensitivity for picking up weak devices, outstanding low noise floor level of -117dBm at 1 signals. GHz of the 3GHz spectrum analyzer performs extreme sensitivity for picking up weak signals. Along with a 20dB-gain preamplifier, the 3GHz spectrum analyzer can further reach an equivalent noise floor level as low as -137dBm, widely extending the measurement range. The transient signal optimization on this spectrum analyzer enables measurement of the power in rapid grasping the EMI sources. These capabilities make the 3GHz spectrum analyzer uniquely suited to solving today’s EMI problems. The requirements of Electromagnetic compliance testing Fig. 1. Using GKT-006 Probes for EMI Emission has become the key indicator to forecast the market Diagnosis Systems that have been well adopted for potential for 3GHz Spectrum Analyzer EMC/EMI pre-test of electronic product before delivering Electromagnetic compliance (EMC) remains a hot topic to EMI certification Lab, for example. among regulatory groups and manufacturers. With the continued integration of electronics in consumer devices, Along with a transports along other electronic devices or there will be a significant increase in the number of component. And the radiated EMI caused by the possible electromagnetic sources present in any given unwanted signal of harmonics generated from the system environment. EMC testing, therefore, is necessary to case, antenna or electronic component transmits as a guarantee the safe and effective operation of such electromagnetic wave to distort other electronic systems. products. To combat the risks associated with www.instek.com GOOD WILL INSTRUMENT CO., LTD. The optimal solution to ensure the excellent certification quality of EMI testing 3 electromagnetic interference (EMI), product With their small footprints and portable nature, such manufacturers are adopting spectrum analyzers as products allow for utility both in the field and on the reliable tools for EMC testing. Typically lightweight and bench. Despite the increased use of handheld devices, feature-rich, spectrum analyzers can be used in spectrum-analyzer vendors must realize that their conjunction with antennas, line impedance stabilization revenues may be hindered by the availability of previously networks (LISNs), and near-field probes to find EMI used systems currently in the market, which are prime radiation sources. The use of spectrum analyzers often options for R&D engineers who wish to minimize saves time and money for engineers who do not wish to operating costs. Even with used systems available, the travel to an EMC lab for their compliance tests. Spectrum mature spectrum analyzer market will continue to analyzers that can handle an 3~20GHz frequency range experience modest growth, given its importance in EMC are well suited for examining satellite communications testing. There depicts market revenues from 2003 to 2007 systems’ operations, testing communications equipment, and expected revenues for 2008 in Fig.2. With a high and fulfilling wireless system commissioning and degree of market competition and price sensitivity, troubleshooting. The communications industry is vendors must understand the importance of developing perhaps the most important area of growth for spectrum products with enough features and capabilities to satisfy analyzers, as this sector continues to witness the the testing needs of end users. deployment of new wireless networks and standards that must be tested for EMI. As technologies such as WiMAX, EMI Measurement Overview 3G wireless, and WCDMA continue to evolve, they are With a compact spectrum analyzer, the manufacturers expected to contribute a significant proportion of making electronic products can easily build up the revenues to the overall spectrum-analyzer market. production line for EMI testing or electronic system Although spectrum analyzers have been known for their designer can have the technical capability to develop the somewhat hefty price tag in the past, the introduction of high the capacity have been adopted by way of radiated lower- cost testers has made such devices more EMI ad Conducted EMI. For a formal EMI certification affordable and desirable to many end users. This is test, in either an EMI chamber or an open field site, the largely attributed to vendors who have moved toward the receiving antenna will pick up the emissions with in a development of less-expensive handheld devices. distance of 8 or 10 meters. This means the emissions may come from anywhere within the DUT. The antenna will receive them all the emissions, they can come from the top, bottom, right or left hand side. Fig. 2. There is a wide range of human risk associated with electromagnetic interference Fig. 3. EMI testing in Open side. www.instek.com GOOD WILL INSTRUMENT CO., LTD. The optimal solution to ensure the excellent certification quality of EMI testing 4 In Fig.3, the DUT is placed on a rotatable table, the with plastic so that short circuits to the DUT are avoided. receiving antenna is located 10 meters from the DUT, and Different types of probes are chosen to fit different its stature is adjustable. The antenna output is connected frequencies and DUT shapes. The tip probe is a direct to a spectrum analyzer which is located in a shielded touch probe which allows the probe tip to directly test the room. A perfect Ground is needed to ensure an isolated circuits. Even though there is no ground connection to environment. During the measurement, the table will the probe the FR signal can still be measured for spot rotate 360 degrees, so that the antenna can receive the testing and location measuring. omni directional emissions. The antenna is also vertically adjustable to catch the upward emissions. However, the A Spectrum analyzer is the most widely used instrument EMI testing results can not distinguish where on the DUT for EMI emission measurements. A spectrum analyzer the emissions were generated. When the emissions are provides the frequency and strength information of too strong and fail to pass regulations, the source needs signals. With the use of a moving probe the source to be suppressed and thus have to be identified first. The location of emissions can be found rapidly. For diagnostic near field probe is used to find the source of emissions on purposes, it is recommended that our spectrum analyzer the DUT. is used in the “Peak Hold” trace mode to record emissions. If emissions are weak, an additional preamplifier can be used for amplifying emissions for measurement. Besides, the 3GHz spectrum analyzer can be an automatic test instrument instead of external computer control. Users can define their own macros through keypad on the front panel and store them into sequence sets at most. Each sequence including pause Fig. 4. Moving the probe around the DUT steps, which can be paused at the instant while observing the measurement result. The quick EMI pretest can be The GKT-006 is a near field probe set which is used to implemented on spectrum analyzer with EMI filter. connect to a spectrum analyzer (in most of cases) to detect the E or H field. The detection is done by holding the probe and moving it around the DUT as shown in Fig.4. When the probe is moved to the vicinity of the source, the E/H field will be inducted through the probe, showing the measured strength on the spectrum analyzer. The emission source can be located accordingly. During the operation, the probes (two loop and one stub probe) are used by means of “non-direct touch” so the probes will induct the E/H field. The probes are insulated www.instek.com Fig. 5. The typical 3GHz Spectrum Analyzer GOOD WILL INSTRUMENT CO., LTD. The optimal solution to ensure the excellent certification quality of EMI testing 5 the configuration as shown in Fig.9. This connection is well performed on spectrum analyzer instead of the oscilloscope that can’t activate the RF detection kit without 50Ω input impedance. Fig. 6. The main tool of EMI diagnostic package Fig. 8. BNC probe Connections is well-posed with RF cable and loop probes ANT-01, ANT-02 and ANT-03, which enable to measure the background noise of peripheral signal from TV or radio. Fig. 7. The EMI-specific software installed in EMI diagnostic package Interfaces and Connections of EMI Measurement The probes have different connector types due to their characteristics. When a probe is connected to a spectrum analyzer, a suitable adapter is needed. Possible connections are as follows. 1. When the loop probes ANT-01, ANT-02 and ANT-03 are connected to a spectrum analyzer, an N to BNC adapter (ADP-01) is needed because these probes Fig. 9. Correct connections is well-posed with SMA cable are BNC type connectors. The cable used in the and probe detector PR-03 to track the circuit conduction GKT-006 is a test lead with BNC connectors at both 2. ends. In terms of a spectrum analyzer set-up, we shall have the One can use probe detector PR-03 to point out and primary setting of frequency range by scanning two zones, track the conduction properties of electrical circuit by 30MHz~300MHz and 300MHz~1GHz under 120KHz of www.instek.com GOOD WILL INSTRUMENT CO., LTD. The optimal solution to ensure the excellent certification quality of EMI testing 6 RBW setting. At first, enter the function key ”Trace” and To attain the highly precision in robot movement along select “Peak” to pick out the main sources of largest the process chambers on equipment is significantly noise level by sequence as “Trace” then “More” then affected by the normal programmable operation. And the “Detection”. In terms of the further advanced test, we preventive maintenances of the equipment often spent can choose the major source of noise peak120MHz, for much time and efforts while going for the preliminary example. Assign the center frequency as this noise check with conducted EMI calibration as shown in peak120MHz and set the frequency span to 4MHz. Then Fig.11. select “Detection”, then enter ”Q Peak”, and use “AVG” to pick out the maximum and average value which will be the practical way. Example 1. Quickly checking the conduction properties of electrical circuit Fig. 11. It takes much time for certification connection for normal conducted EMI, which can cost-efficiently adopt the pre-test measurement by simple EMI emission detection. The profound influence Pre-test by Spectrum analyzer Measurement System on Conducted EMI certification Fig. 10. Optimal solution of EMI emission Measurement The noise sources can be decomposed into common mode noise and differential mode noise. These two As shown in Fig.10, applying kits of loop probes to components of noise sources are respectively caused by proceed in simple tracking the EMI characteristics will their associated current. The noise can be extracted from make it possible to save much more time in testing site the line impedance stabilization network (LISN), shown in of production line. There are kits including ANT-01, BNC Fig.12, the measured value after feed through noise cable, ADP-01 and a 10dB pre-amplifier GAP-802 to separator can be acquired by spectrum analyzer. With a capture the EMI emission source in this figure. EMI detection bundled on a 3GHz spectrum analyzer, Either involving the commitments of EMI detection or Example 2. The Pre-test Measurement for the Advanced simply build the easy connection may allow you to get rid Test on the Process Equipments in Semiconductor of most of the EMI troublesome. Manufacturing Sector www.instek.com GOOD WILL INSTRUMENT CO., LTD. The optimal solution to ensure the excellent certification quality of EMI testing 7 by rapidly identifying the issues. This can prevent the lengthy setbacks that can occur with outdated and inefficient test equipment. DUT References  A, Krusubthaworn, R. Sivaratana, V. Ungvichian, A. Siritaratiwat., Testing parameters of TMR heads affected by dynamic-tester induced EMI, Journal of Magnetism Spectrum Analyzer and Magnetic Materials 316(2007) e142-e144. Fig. 12. Measurement system for Conducted EMI. As an approach to killer application, 3GHz spectrum analyzer inherits the advantages if high performance, affordable cost, easy to use and light-weight portability. Moreover, its extremely low noise floor greatly increases the measurement range, advanced user interface brings users with significant visual enhancement, and versatile powerful functions make measurements simple and accurate. The 3GHz spectrum analyzers have been offers with the greatest performance-to-price ratio in the market. Using the 3GHz spectrum analyzer as a EMI/EMC pre-test measurement tool will likely eliminate the possibility of measurement algorithm errors after addressing the EMI testing in certification lab. The leadership of 3GHz spectrum analyzer in delivering the test industry’s first dedicated EMI measurement suite has given it rapid adoption by a wide range of EMI/EMC certification. There is a very good chance that one’s electronic product will successfully undergo EMI/EMC certification test with the 3GHz spectrum analyzer making many of the measurements. If an issue does arise during the EMI/EMC test, having the easily portable single box SA available provides a means to quickly troubleshoot circuits. The 3GHz spectrum analyzer can help the engineer rescue the EMI/EMC effort www.instek.com GOOD WILL INSTRUMENT CO., LTD. The optimal solution to ensure the excellent certification quality of EMI testing 8 www.instek.com GOOD WILL INSTRUMENT CO., LTD.
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