Re: antenna port conducted emissions
Do you need to look at non-fundamental, non-harmonic emissions as well? There will be such emissions as well. Some will be visible with the source in CW mode, but there will be others that appear only during frequency hopping. These latter emissions are harder to find since their frequencies are not known well. They can appear in band or out of the band of operation. The techniques described in other postings still apply. Don Borowski Schweitzer Engineering Labs Pullman, WA "Low, Aaron S" @majordomo.ieee.org on 03/19/2003 07:43:49 AM Please respond to "Low, Aaron S" Sent by:owner-emc-p...@majordomo.ieee.org To:emc-p...@majordomo.ieee.org cc: Subject:antenna port conducted emissions Folks, I am interested in your opinions regarding antenna port conducted emissions (MIL-STD-461D CE106) on a spread spectrum/frequency hopping device. Is it practical to automatically measure (using a swept scan EMI receiver) emissions from such a device? I would think that when using spread spectrum and a swept scan receiver, the receiver has some large probability of missing the emissions caused by a particular harmonic when using swept scanning systems. The limit for CE106 (transmitters) is derived from the power of the fundamental (there is no fundamental, only a band of operation), how do you measure that power on the EMI receiver? Does anyone have any experience/advice they would be willing to part with? Thanks Aaron Low ps. I am relatively new to this field, so my question may seem very basic to many of you; please excuse me. 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: davehe...@attbi.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: davehe...@attbi.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: antenna port conducted emissions
Aaron, I believe you use the standard receiver RBW and use the peak hold mode. Depending on how the spread spectrum operates (I.E. wideband "noise", or frequency hopping, etc.) the receiver and the transmitter will eventually line up. Dave Cuthbert From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Wednesday, March 19, 2003 11:10 AM To: 'Low, Aaron S'; emc-p...@majordomo.ieee.org Subject: RE: antenna port conducted emissions >-Original Message- >From: Low, Aaron S [mailto:aaron.s@lmco.com] >Sent: Wednesday, March 19, 2003 7:44 AM >To: emc-p...@majordomo.ieee.org >Subject: antenna port conducted emissions > > > >Folks, > >I am interested in your opinions regarding antenna port >conducted emissions >(MIL-STD-461D CE106) on a spread spectrum/frequency hopping device. > >Is it practical to automatically measure (using a swept scan >EMI receiver) >emissions from such a device? I would think that when using >spread spectrum >and a swept scan receiver, the receiver has some large probability of >missing the emissions caused by a particular harmonic when using swept >scanning systems. > >The limit for CE106 (transmitters) is derived from the power of the >fundamental (there is no fundamental, only a band of >operation), how do you >measure that power on the EMI receiver? > >Does anyone have any experience/advice they would be willing >to part with? > >Thanks >Aaron Low > >ps. I am relatively new to this field, so my question may >seem very basic >to many of you; please excuse me. > > Aaron: First question is are you sure you should be working to 461D? 461E came out 20 August 1999. Now, to address your technical situation. Yes, you do have a fundamental. Just because it's hopping doesn't mean it's not there. Granted, 461 CE06 (later CE106) originated in the era of non-hopping systems, and may address them better in a future revision, but it does say that your reference will be the peak power level of the fundamental. You can measure the peak power by using a spectrum analyzer in peak hold, using sufficient bandwidth to ensure the detector actually charges to the peak during the time that the fundament dwells in the SA resolution bandwidth. Sometimes you can sweep a small portion of spectrum, or you can go to zero span width and just sit at some frequency waiting for the fundamental to hop there. You may find that the fundamental amplitude varies across the hopping range, so you might need to disable the hopping and fix the fundamental to one or more specific frequencies. Remember when looking for harmonic content, the hop sizes will be n x the fundamental hop size. Probabability of intercept is a problem, and I usually scan very slowly and do several overlaid sweeps of the spectrum. Many of the transmitters that I see have a short duty cycle (like 7 uS on and 993 uS in standby), so this makes the signal acquisition even more "challenging". Sometimes I set automated scans to run 16 hours overnight, or over a weekend. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis 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: davehe...@attbi.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: davehe...@attbi.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: antenna port conducted emissions
>-Original Message- >From: Low, Aaron S [mailto:aaron.s@lmco.com] >Sent: Wednesday, March 19, 2003 11:49 AM >To: emc-p...@majordomo.ieee.org >Subject: RE: antenna port conducted emissions > > > >I'd like to thank all those who replied so far. > >According to MIL-STD-462D: > >4.9.2 Operating frequencies for spread spectrum equipment. >Operating frequency requirements for two major types of spread spectrum >equipment shall be as > follows: > a. Frequency hopping. Measurements shall be performed >with the EUT >utilizing a hop set > which contains a minimum of 30% of the total possible >frequencies. This hop set shall > be divided equally into three segments at the >low, mid, and >high end of the EUT's > operational frequency range. > b. Direct sequence. Measurements shall be performed with the EUT >processing data at the > highest possible data transfer rate. > >Can I interpret this section to mean that when scanning for emissions, >standard MIL-STD scanning methods apply? > >Aaron > > Aaron S. Low > Systems Engineer >Naval Electronics and Surveillance Systems >EP5 D5 MD45 Syracuse, NY 13221-4840 >Phone: (315) 456-1203Fax: (315) 456-0509 >L I interpret 4.9.2.a as trying to ensure that you are not playing tricks with the selection of frequencies. For instance, at the low end of your hop range, your circuit might generate higher harmonic content, so you decide to choose a hop set that's all in the upper 1/3 of the range. No, uh-uh, not prudent, shouldn't do that. If by "methods", you mean scanning speed, in MHz per second, then remember that Paragraph 4.3.10.3.1, Table II is only a set of maximum speed limits. Notice that 4.3.10.3.3 says "For equipment that operates such that the potential emissions are produced at only infrequent intervals, times for frequency scanning shall be increased as necessary to capture any emissions." As I said earlier, you may have to scan much slower than the speed limit. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis 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: davehe...@attbi.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: antenna port conducted emissions
I'd like to thank all those who replied so far. According to MIL-STD-462D: 4.9.2 Operating frequencies for spread spectrum equipment. Operating frequency requirements for two major types of spread spectrum equipment shall be as follows: a. Frequency hopping. Measurements shall be performed with the EUT utilizing a hop set which contains a minimum of 30% of the total possible frequencies. This hop set shall be divided equally into three segments at the low, mid, and high end of the EUT's operational frequency range. b. Direct sequence. Measurements shall be performed with the EUT processing data at the highest possible data transfer rate. Can I interpret this section to mean that when scanning for emissions, standard MIL-STD scanning methods apply? Aaron Aaron S. Low Systems Engineer Naval Electronics and Surveillance Systems EP5 D5 MD45 Syracuse, NY 13221-4840 Phone: (315) 456-1203Fax: (315) 456-0509 L From: Low, Aaron S [mailto:aaron.s@lmco.com] Sent: Wednesday, March 19, 2003 10:44 AM To: emc-p...@majordomo.ieee.org Subject: antenna port conducted emissions Folks, I am interested in your opinions regarding antenna port conducted emissions (MIL-STD-461D CE106) on a spread spectrum/frequency hopping device. Is it practical to automatically measure (using a swept scan EMI receiver) emissions from such a device? I would think that when using spread spectrum and a swept scan receiver, the receiver has some large probability of missing the emissions caused by a particular harmonic when using swept scanning systems. The limit for CE106 (transmitters) is derived from the power of the fundamental (there is no fundamental, only a band of operation), how do you measure that power on the EMI receiver? Does anyone have any experience/advice they would be willing to part with? Thanks Aaron Low ps. I am relatively new to this field, so my question may seem very basic to many of you; please excuse me. 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: davehe...@attbi.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: davehe...@attbi.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: antenna port conducted emissions
>-Original Message- >From: Low, Aaron S [mailto:aaron.s@lmco.com] >Sent: Wednesday, March 19, 2003 7:44 AM >To: emc-p...@majordomo.ieee.org >Subject: antenna port conducted emissions > > > >Folks, > >I am interested in your opinions regarding antenna port >conducted emissions >(MIL-STD-461D CE106) on a spread spectrum/frequency hopping device. > >Is it practical to automatically measure (using a swept scan >EMI receiver) >emissions from such a device? I would think that when using >spread spectrum >and a swept scan receiver, the receiver has some large probability of >missing the emissions caused by a particular harmonic when using swept >scanning systems. > >The limit for CE106 (transmitters) is derived from the power of the >fundamental (there is no fundamental, only a band of >operation), how do you >measure that power on the EMI receiver? > >Does anyone have any experience/advice they would be willing >to part with? > >Thanks >Aaron Low > >ps. I am relatively new to this field, so my question may >seem very basic >to many of you; please excuse me. > > Aaron: First question is are you sure you should be working to 461D? 461E came out 20 August 1999. Now, to address your technical situation. Yes, you do have a fundamental. Just because it's hopping doesn't mean it's not there. Granted, 461 CE06 (later CE106) originated in the era of non-hopping systems, and may address them better in a future revision, but it does say that your reference will be the peak power level of the fundamental. You can measure the peak power by using a spectrum analyzer in peak hold, using sufficient bandwidth to ensure the detector actually charges to the peak during the time that the fundament dwells in the SA resolution bandwidth. Sometimes you can sweep a small portion of spectrum, or you can go to zero span width and just sit at some frequency waiting for the fundamental to hop there. You may find that the fundamental amplitude varies across the hopping range, so you might need to disable the hopping and fix the fundamental to one or more specific frequencies. Remember when looking for harmonic content, the hop sizes will be n x the fundamental hop size. Probabability of intercept is a problem, and I usually scan very slowly and do several overlaid sweeps of the spectrum. Many of the transmitters that I see have a short duty cycle (like 7 uS on and 993 uS in standby), so this makes the signal acquisition even more "challenging". Sometimes I set automated scans to run 16 hours overnight, or over a weekend. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis 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: davehe...@attbi.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
