RE: Conducted immunity of a USB port
Thanks Ken, I do vaguely remember reading that normative section before but I've always had products where the cables have included an AC port (or connection to a power plant) and/or 'long' IO metallic interfaces which in essence mandates the 150kHz start frequency. Andy ___ From: ext Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Wednesday, November 19, 2003 8:59 AM To: White Andy (NMP/SanDiego); pa0...@mubo.nl; emc-p...@majordomo.ieee.org Subject: Re: Conducted immunity of a USB port My 1996 release of IEC 1000-4-6 has an informative Appendix B that states the start frequency is the speed of light divided by the sum of the cable length and EUT size. If people are not doing this for short cable runs, they are over-testing at low frequencies by orders of magnitude. From: andy.wh...@nokia.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Wed, 19 Nov 2003 08:20:50 -0800 To: , , Subject: RE: Conducted immunity of a USB port The EM clamp can be used but the preferred method would be using a CDN or direct injection to the screen. I could not find the reference to start the testing at higher than 150kHz within 61000-4-6. [Perhaps I missed that bit?] I am surprised that the CDN for the screen did not work as I have tested 100bT Ethernet screened cable and T1 screened cables using suitable CDNs to inject on to the screen. The functionality of the port was not degraded by the CDN. I would verify/re-check your 'home made' adapters. Andy ___ Andy White EMC Engineer Nokia, San Diego ___ From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of ext Ken Javor Sent: Tuesday, November 18, 2003 7:32 PM To: Ton Bouw; emc-p...@majordomo.ieee.org Subject: Re: Conducted immunity of a USB port I can only answer parts of this question. You should test for the maximum length the USB interface could attain, but since that length is 5 meters in this case, the limit lower frequency should be tailored upwards to account for that. There is no use testing at 150 kHz on such a short cable. This is right out of IEC 61000-4-6. If CDN design presents obstacles to testing high speed USB, I think an EM clamp is a better approach. In fact, I believe an EM clamp is a better approach for any shielded cable. The point of a CDN is to inject a signal into an equipment connector pin. When a cable is shielded, the mechanism for getting the rf signal on a pin is the transfer impedance of the shield. In order to test that, you need to get current flowing down the length of the shield. I think an EM clamp is a better mechanism for achieving that. From: Ton Bouw Reply-To: Ton Bouw List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tue, 18 Nov 2003 23:51:07 +0100 To: emc-p...@majordomo.ieee.org Subject: Conducted immunity of a USB port Dear group, I have the following questions on testing a USB port for conducted immunity 1) USB extension cables are available in the consumer market. The USB 1.0 spec limits the cable length to 5.0m. Therefor I believe that the conducted immunity test is required even if the cable length of the DUT is less than 3m, unles a restriction is made in the user manual.. Is that correct? 2) I tested conducted immunity using a CDN-S9 with home-made adaptors from DB9 to USB using 4 pins of the DB-9 and the screen connection. I assume that this should give a representative result? For information: this does not work for hi-speed USB because of the LPF in the CDN. 3) Are CDN's for USB available? Or is it better to use an EM clamp? kind regards, Ton Bouw
RE: Conducted immunity of a USB port
The EM clamp can be used but the preferred method would be using a CDN or direct injection to the screen. I could not find the reference to start the testing at higher than 150kHz within 61000-4-6. [Perhaps I missed that bit?] I am surprised that the CDN for the screen did not work as I have tested 100bT Ethernet screened cable and T1 screened cables using suitable CDNs to inject on to the screen. The functionality of the port was not degraded by the CDN. I would verify/re-check your 'home made' adapters. Andy ___ Andy White EMC Engineer Nokia, San Diego ___ From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of ext Ken Javor Sent: Tuesday, November 18, 2003 7:32 PM To: Ton Bouw; emc-p...@majordomo.ieee.org Subject: Re: Conducted immunity of a USB port I can only answer parts of this question. You should test for the maximum length the USB interface could attain, but since that length is 5 meters in this case, the limit lower frequency should be tailored upwards to account for that. There is no use testing at 150 kHz on such a short cable. This is right out of IEC 61000-4-6. If CDN design presents obstacles to testing high speed USB, I think an EM clamp is a better approach. In fact, I believe an EM clamp is a better approach for any shielded cable. The point of a CDN is to inject a signal into an equipment connector pin. When a cable is shielded, the mechanism for getting the rf signal on a pin is the transfer impedance of the shield. In order to test that, you need to get current flowing down the length of the shield. I think an EM clamp is a better mechanism for achieving that. From: Ton Bouw Reply-To: Ton Bouw List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tue, 18 Nov 2003 23:51:07 +0100 To: emc-p...@majordomo.ieee.org Subject: Conducted immunity of a USB port Dear group, I have the following questions on testing a USB port for conducted immunity 1) USB extension cables are available in the consumer market. The USB 1.0 spec limits the cable length to 5.0m. Therefor I believe that the conducted immunity test is required even if the cable length of the DUT is less than 3m, unles a restriction is made in the user manual.. Is that correct? 2) I tested conducted immunity using a CDN-S9 with home-made adaptors from DB9 to USB using 4 pins of the DB-9 and the screen connection. I assume that this should give a representative result? For information: this does not work for hi-speed USB because of the LPF in the CDN. 3) Are CDN's for USB available? Or is it better to use an EM clamp? kind regards, Ton Bouw
RE: GR-1089 Issue 3: 3.2.1 Radiated Emission Criteria
Hi Richard, I used to deal with GR1089 testing with my previous employer. The way I used to specify the test plans were to complete the emissions tests with 'doors open' and 'doors closed'. This would allow the GR1089 criteria to be met and also the FCC criteria to be met. I know that it means repeating certain test frequency ranges but the FCC tests must be met for almost all carriers. GR1089 is not a legal requirement, it is good to meet it (especially with Verizon or to co-locate with Verizon) but the FCC is a regulatory requirement and is good to have to sell in other market areas. An example of what I mean is shown below. [1] E-Field - Enc. (Doors Closed) GR-1089-CORE R3-1[8] 10k to 30M Class A E-Field - Enc. (Doors Closed) FCC part 15, EN55022, GR1089-CORE R3-1[8] 30M to 1G Class A E-Field - Enc. (Doors Closed) FCC part 15, GR-1089-CORE R3-1[8] 1G to 10G Class A E-Field - Enc. (Doors Open) GR-1089-CORE R3-3[10] 10k to 30M Class A E-Field - Enc. (Doors Open) GR-1089-CORE R3-3[10] 30M to 10G Class A H-Field - Enc. (Doors Open) GR-1089-CORE R3-4[11] 60hz to 30M Class A [1] H-Field - Enc. (Doors Closed) GR-1089-CORE R3-1[8] 60Hz to 30M Class A [1] perform doors closed only if doors open criteria is not met. Andy ___ Andy White EMC Engineer Nokia San Diego ___ From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of ext Georgerian, Richard Sent: Tuesday, November 18, 2003 8:31 AM To: IEEE emc-pstc Subject: GR-1089 Issue 3: 3.2.1 Radiated Emission Criteria Greetings All, Hopefully someone has some insight to the following- In GR-1089 Issue 3, Section 3.2.1, requirement R3-1 [8] uses the FCC Class A and B limits for equipment with no doors or covers for the range of 30MHz to 1GHz. It also has limits for below 30MHz and above 1GHz. This section I understand. What I don't understand clearly is requirement R3-3 [10]. It references emissions from Class A and B unit's not exceeding Table 3-2. Table 3-2 limits are higher than the FCC Class A and B limits. The doors or covers are to be opened during emission testing. However, if the doors and covers that are not intended to be opened during EUT operation, maintenance, and/or repair need not be opened, I can still test to those higher limits. If so, I can no longer can be considered FCC A or B equipment. Is requirement R3-3 [10] mainly for central office areas and not residential? Thanks. Richard = Richard Georgerian Compliance Engineer Carrier Access Corporation 5395 Pearl Parkway Boulder, CO 80301 USA Tele: 303-218-5748 Fax: 303-218-5503 mailto:rgeorger...@carrieraccess.com
RE: Window of Uncertainty
The FCC does not allow any units (sold on the marketplace) to be 'above' the FCC limits. It is therefore prudent to ensure that 'all' finished production units comply with the FCC limits taking in to account manufacturing build tolerance/variability, product design tolerance/variability and final laboratory measurement uncertainty. Which basically leads to ensuring that your product has a designed in emissions 'margin' that will provide compliance for units leaving the production floor. In my experience during initial product development EMC testing/qualification you have to pursue to attain as much 'margin' as possible. To let a product through certification with a minimalist margin at the beginning of marketing product launch will only make subsequent product design changes/updates much more difficult to certify. Andy _ Andy White EMC Engineer Nokia Mobile Phones San Diego, CA Tel 858 831 4534 andy.wh...@nokia.com _ From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of ext Dave Grant Sent: Thursday, October 30, 2003 5:02 PM To: emc-p...@majordomo.ieee.org Subject: Window of Uncertainty Hello all, We have been doing development of our product here and have been testing the conducted emissions with respect to CISPR 14.1. There is a window of uncertainty of +/- 3dBuV with respect to this test? The testing here that has taken place so far shows that the product fails by 0.5 dBuV at a certain frequency. My question is, is this an Assumed Pass as this fall within the Window of Uncertainty? or Is any measurement above the limit irrespective of the uncertainty error a fail? This is with for the European, Australasian and American markets. Cheers ... Dave This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: CISPR22 applicability for ITE
Alex, CISPR22 can be used but do not override the FCC requirements e.g. part 15.33 indicates for intentional radiators testing up to the 10th harmonic of the fundamental (if the fund. is below 10GHz) or test up to 40GHz which ever is lower. Also for unintentional radiators the highest frequency generated within the device also indicates the upper freq. of measurement e.g. for signals being generated within the EUT between 500MHz to 1000MHz, test up to 5GHz. CISPR22 does not mandate testing above 1GHz and most ITE (nowadays)will require testing above 1GHz to meet the requirements of FCC rules. Andy _ Andy White EMC Engineer Nokia Mobile Phones San Diego, CA Tel 858 831 4534 andy.wh...@nokia.com _ From: ext Alex McNeil [mailto:alex.mcn...@ingenicofortronic.com] Sent: Friday, October 10, 2003 1:22 AM To: emc-p...@majordomo.ieee.org Subject: CISPR22 applicability for ITE Hi Guys, Q1: Is it true that USA and Canada accept CISPR22:1997/A1:2000 instead of FCC Part 15 and ICES-003? and only if tested per ANSI C63-4:2002 methods? Q2: Is it true that Australia now accepts EN55022:1998 or CISPR22:1997+A1:2000 and/or CISPR22:2003 4th Edition? Kind Regards Alex McNeil Principal Engineer This email has been scanned for all known viruses and appropriate content by the Messagelabs mail service. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Q on FCC and CISPR data
Charles, As far as I am aware the FCC regs now use the CISPR22 conducted emissions limits for the AC mains port and the radiated emissions measured at 3m for a class B device. CISPR22 radiated emissions are measured at 10m (for Class A and Class B) and are not measured at 3m (as per the FCC set up for Class B devices). So it may be possible (and valid) to have a FCC Class B report with RE at 3m (using FCC RE set up) and CISPR22 AC mains port conducted emissions but not valid to have a FCC Class (A or B) report with RE at 3m using CISPR22 RE limits. Andy _ Andy White EMC Engineer Nokia Mobile Phones San Diego, CA Tel 858 831 4534 andy.wh...@nokia.com _ From: ext Charles Grasso [mailto:cgrassospri...@earthlink.net] Sent: Tuesday, August 12, 2003 9:38 PM To: Emc-Pstc Subject: Q on FCC and CISPR data All, In order to harmonize fully with the ROW, the FCC has amended Part15 to include the CISPR conducted limits with a transition period. Heres my question: Can one now mix and match limits? For example, I reviewed a Class B report only to discover that the radiated emissions were done to FCC (@3M) and the conducted to CISPRB. Is this OK and by that I mean legal. I don't like it:- I think one selects the desired limits FCC or CISPR and tests all FCC or all CISPR. Comments as always welcome (especially from test houses) Charles Grasso This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: GR1089 4.5.9 Intrabuilding Lightning Strike Telecom Ports
Jeffrey, In a previous life with a large multi-national manufacturer of base stations and base station controllers, I went through the same issue. Using the grounded cable shield (at both cable ends) to waiver the Intra-building surge requirement. The product requirement was changed to meet intrabuilding for ethernet, RS232 and then full 2nd level surge & AC power cross on T1. Performing Intra-building surge on Ethernet, T1 and RS232 ports is problematic and sometimes catastrophic. The cable shield made no difference to the test results. Applying the surge direct to the conductors as detailed in GR1089 with the surge applied to a single conductor in turn and the remaining 3 conductors grounded (for a 4 wire i/f) is severe and protection needs to be designed in at pcb level to protect the port. T1 ports are usually transformer coupled and the transformers are normally rated for 1500V common mode protection. Differential surges will probably be the issue. The same applies to ethernet ports. Protection can be designed at pcb level to protect the port and care must taken to select protection that does not load the lines with too much capacitance or the port will not function. The ethernet port is very sensitive to capacitive loading. RS232 ports are not transformer coupled and fast TVS diode arrays can be used to meet Intra-building surge. Intra-building surge can be met for these type of ports, 2nd level surges & AC power cross is also possible but careful designed in protection to match the interface circuitry is reqd. Andy _ Andy White EMC Engineer Nokia Mobile Phones San Diego, CA Tel 858 831 4534 andy.wh...@nokia.com _ From: ext Collins, Jeffrey [mailto:jcoll...@ciena.com] Sent: Friday, June 13, 2003 5:08 AM To: emc-p...@majordomo.ieee.org Subject: GR1089 4.5.9 Intrabuilding Lightning Strike Telecom Ports All, We have taken the waiver to this requirement by using shielded cables that were grounded on both ends. Since it is common for carriers to float one end of their grounds we are planning to perform this test on our telecom ports. Looking at the levels of the surge in table 4-4, I'm not confident that a grounded shielded telcom cable would make the difference in passing this test. ( Surges are at 800V and 1500V) ( Ports / Cables are T1, E1, Ethernet, and RS232) My plan is to run this test with both unshielded ungrounded cables and shielded grounded cables. Does anyone have any experience in passing this test where the shielded/grounded cable made the difference? Anyone have a theoretical opinion/prediction on this? Thanks in advance, Jeffrey Collins Sr. HW Engineering Manager EMC/ NEBS/ Reliability/ Safety CIENA Corporation 5965 Silver Creek Valley Rd. San Jose, CA. 95138 (408) 571-3002, Fax (408) 965-2705 jcoll...@ciena.com http://www.ciena.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
