Extending the National EMC Instrumentation Standard to Frequencies Below 10 kHz

The paper discusses the measurement standards and applications for an Audio Frequency EMI Analyzer and how these diverse needs may be met by a standard­ ized instrument. Some background is given on ANSI C63.2, which is THE U. S. national standard for EMC measurement instrumentation, and its role in providing manufacturers and users in divergent application areas with a common standard to assure highly economical and technically sound instrumentation. Summary For many years, the U. S. national standard on EMC measuring instrumentation has failed to cover the audio frequency range. Its lower boundary was origin­ ally 150 kHz, later this was lowered to 14 kHz, and it is currently 10 kHz in ANSI C63.2 [1]. However, more and more needs have surfaced for a standardized instru­ ment with coverage down to 10 Hz or 20 Hz. Defacto instrument standards have been implied from time—to— time by measurement methods used in various application TABLE I. SUMMARY OF STANDARD EMC MEASUREMENTS, A.F. TO L.F. Standard Method Freq. Range (Hz) Measurement MIL-STD-461B CE01 CS01 CS09 RE01/RE04 RS01 30 to 15k 30 to 50k 60 to 100k 30 to 50k 30 to 50k Cond. Emissions, NB & BB Cond. Suscep., NB3 Cond. Suscep., NB3 Rad. Emissions, NB,, H-Fld.1 Rad. Suscep., NB, H-Fld.3 SL-E-0002, Rev. A (Space S hu tt le )2 CE01 CS01 30 to 20k 30 to 50k Cond. Emissions, NB & BB Cond. Suscep., NB3 MIL-STD-1541 (USAF) 115.1.2.2.1 0.1 to »10k Cond. Emissions, Pwr & Sig. Lines MSFC-SPEC-521A 113.2.1.1.1 H3.2.1.2.3 113.2.2.1.1 113.2.2.2.2 30 to 20k 20 to 50k 30 to 50k 30 to 50k Cond. Emission, DC Pwr Bus Rad. Emissions, H-Fld Cond. Suscep., NB3 Rad. Suscep., NB, H-Fld3 MDS-201-0004 1979 (FDA) 113.2.2 H3.3.2 500 to 30M 100 to 50k Cond. Emission, NB Cond. Suscep., NB3 MIL-STD-285A (Draft '82) NSA 65-6, and IEEE-299A (Draft ‘84) — 900 to 16k Rad. Shielding Effec. Measurements (H-Fld) NACSIM-5100A1* — 100 to »10k Cond. & Rad. Emis., NB & BB CISPR Pub 16-1977 Section 6 10 to 20k Cond. & Rad. Emis. IEC 555-2 115.2.4 150 to 2.5k Cond. Emis., Pwr Cir Harm. CCITT Rec. & CCIR-468 — 16 to 16k Psophometric Voltmeter5 Notes: 'The requirement in MIL-STD-461B appears to be a combination of both RE01 and RE04 in MIL-STD-461A/462 2Used with MIL-STD-461A instrum ent used as tuned vo ltm eter /f ie ld strength meter to monitor Suscepti­ b i l i t y te s ts ‘'Needs special charac ter is t ics 5Needs special pass band shape CH2294-7/86/000-0008 $01 .00(c )l986 IEEE 8 SESSION 2A areas such as MIL-STD-462 [4] and CCIR Recommendation 468 [8]. Other test methods and applications have appeared over a period of time [1, 2, 3, 4, 5, 6, 7, 8, etc.]. It is clear that C63.2 must be extended to include these audio frequency measurements; in fact, such an extension is well past due! A task group has been working in Subcommittee 1, Techniques and Develop­ ments, of Accredited National Standards Committee C63 for about five years to develop an extension of C63.2 down to 20 Hz. However, up until about a year ago, the scope of the document, as the task group saw it, was too narrow to produce a widely useful standard in­ strument. This narrow scope problem has been remedied and the task group is well on its way towards produc­ ing practicable specifications for a widely usable standard instrument.