Re: Question on Receiver EMI testing..
I read in !emc-pstc that Hans Mellberg emcconsult...@yahoo.com wrote (in 20021030165345.86510.qm...@web40911.mail.yahoo.com) about 'Question on Receiver EMI testing..' on Wed, 30 Oct 2002: That reminds me of a set-top b-b receiver I was testing long ago. While it met all the class B specs both rad and susc., when placed on top of a TV there were interference issues because of the close proximity! (both from the TV and from the set-top!) Depending on your application, you may often have to test beyond the limits if your clientel is to remain satisfied! Indeed; we had this problem with some early VHS VCRs. Remember that the emission limits relate to 3 m or 10 m separation, not 2 cm! -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- 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 All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Question on Receiver EMI testing..
The real world lives in the near field. Bob Heller 3M Product Safety, 76-1-01 St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252 = Hans Mellberg emcconsultant@yahoo.c To: Cortland Richmond 72146@compuserve.com omGrasso, Charles charles.gra...@echostar.com Sent by: ieee pstc list emc-p...@ieee.org owner-emc-pstc@majordo cc: mo.ieee.org Subject: Re: Question on Receiver EMI testing.. 10/30/2002 10:53 AM Please respond to Hans Mellberg That reminds me of a set-top b-b receiver I was testing long ago. While it met all the class B specs both rad and susc., when placed on top of a TV there were interference issues because of the close proximity! (both from the TV and from the set-top!) Depending on your application, you may often have to test beyond the limits if your clientel is to remain satisfied! = Best Regards Hans Mellberg Regulatory Compliance EMC Design Services Consultant By the Pacific Coast next to Silicon Valley, Santa Cruz, CA, USA office:831-454-9450, cell:408-507-9694, fax:831-454-0755 __ Do you Yahoo!? HotJobs - Search new jobs daily now http://hotjobs.yahoo.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: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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 All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Question on Receiver EMI testing..
That reminds me of a set-top b-b receiver I was testing long ago. While it met all the class B specs both rad and susc., when placed on top of a TV there were interference issues because of the close proximity! (both from the TV and from the set-top!) Depending on your application, you may often have to test beyond the limits if your clientel is to remain satisfied! = Best Regards Hans Mellberg Regulatory Compliance EMC Design Services Consultant By the Pacific Coast next to Silicon Valley, Santa Cruz, CA, USA office:831-454-9450, cell:408-507-9694, fax:831-454-0755 __ Do you Yahoo!? HotJobs - Search new jobs daily now http://hotjobs.yahoo.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: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
FW: Question on Receiver EMI testing..
Charles, I have seen this before during an immunity test. It happened on a commercial product (not ours) on the IF and LO circuitry during a CE Mark test. Specifically, it happened with the feedback trace of an LO PLL used for the IF. The PLL circuitry was unshielded and a small band of frequencies caused a mixing product which totally confused the receiver. The fix was to shield the PLL to prevent the susceptibility. The trace was later buried in the PWB to shield it. Philip Ross Wellington Mgr. Signal Integrity EMI L-3 Communications CSW -Original Message- From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: Tuesday, October 29, 2002 4:48 PM To: emc-p...@majordomo.ieee.org Subject: Question on Receiver EMI testing.. Group, A hypothetical question for you... Should a receiver mounted on an antenna be lit up during an emissions test? The receiver down-converts the received signal?? Thanking you all in advance.. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; mailto:charles.gra...@echostar.com; %20 Email Alternate: chasgra...@ieee.org mailto:chasgra...@ieee.org
RE: Question on Receiver EMI testing..
Hi Charles, I have seen some other replies but I understood your question differently. Are you trying to test the receiver or is it simply a remote front end for your measurement set? I don't know anything significant about the first, but if it is the latter then the receive head should be place very close to the antenna but not so close that it intereferes with the antenna behavior. This is most commonly used at microwave frequencies where cable losses are high, the receive head is located behind the dish (or somewhere equivalnet) where is does not interact with the antenna and then the down feed is at an IF where cable losses are much lower. If this is what you have then the receiver does not have to be illuminated, though it can be, the main concern is that it does not affect the calibration of the antenna in any way. Last time I worried about this I was measuring radiation patterns from 40GHz systems close to 24 years ago. I haven't used this type of receiver for EMC work (yet!). cheers, Colin.. -Original Message- From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: Tuesday, October 29, 2002 6:48 PM To: emc-p...@majordomo.ieee.org Subject: Question on Receiver EMI testing.. Group, A hypothetical question for you... Should a receiver mounted on an antenna be lit up during an emissions test? The receiver down-converts the received signal?? Thanking you all in advance.. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; mailto:charles.gra...@echostar.com; %20 Email Alternate: chasgra...@ieee.org
Re: Question on Receiver EMI testing..
Hypothetical: Should a receiver mounted on an antenna be lit up during an emissions test? The receiver down-converts the received signal?? Sure. It has oscillators whose emissions might cause interference. Even if not required by law (Part 15 and receiver above 960 MHz not a radar detector) it's smart to at least LOOK so you know what it does before selling the thing. If it knocks out (say) the local WLAN's, you'll hear a LOT about it! Cortland --- 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 All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question on Receiver EMI testing..
Adding a bit to Ken's comments. I agree, but I have seen many times when surprise emissions have been created by equipment that was never supposed to do that. Even a simple receiver can have a spurious problem, and I have encountered complicated receivers where T/R switches or electronic clamping circuits have created noise of their own (and very far out-of-band). I would need a good reason to NOT exercise the receiver. 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 -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Tuesday, October 29, 2002 5:36 PM To: Grasso, Charles; emc-p...@majordomo.ieee.org Subject: Re: Question on Receiver EMI testing.. I'm not going to claim to be an expert on this one, but this is my two cent's worth. From the point of view of what rf might leak from the EUT, it seems that an LO or IF would be the main concerns. I don't see how the absence/presence of a receivable signal would affect LO emissions. The amplitude of the IF signal would be proportional to received signal strength, so if the IF were in the band controlled by your emissions limit, that might be important. -- From: Grasso, Charles charles.gra...@echostar.com To: emc-p...@majordomo.ieee.org Subject: Question on Receiver EMI testing.. List-Post: emc-pstc@listserv.ieee.org Date: Tue, Oct 29, 2002, 5:47 PM Group, A hypothetical question for you... Should a receiver mounted on an antenna be lit up during an emissions test? The receiver down-converts the received signal?? Thanking you all in advance.. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; mailto:charles.gra...@echostar.com;nbsp;%20 Email Alternate: chasgra...@ieee.org mailto:chasgra...@ieee.org --- 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 All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Question on Receiver EMI testing..
I'm not going to claim to be an expert on this one, but this is my two cent's worth. From the point of view of what rf might leak from the EUT, it seems that an LO or IF would be the main concerns. I don't see how the absence/presence of a receivable signal would affect LO emissions. The amplitude of the IF signal would be proportional to received signal strength, so if the IF were in the band controlled by your emissions limit, that might be important. -- From: Grasso, Charles charles.gra...@echostar.com To: emc-p...@majordomo.ieee.org Subject: Question on Receiver EMI testing.. List-Post: emc-pstc@listserv.ieee.org Date: Tue, Oct 29, 2002, 5:47 PM Group, A hypothetical question for you... Should a receiver mounted on an antenna be lit up during an emissions test? The receiver down-converts the received signal?? Thanking you all in advance.. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; mailto:charles.gra...@echostar.com;nbsp;%20 Email Alternate: chasgra...@ieee.org mailto:chasgra...@ieee.org
Question on Receiver EMI testing..
Group, A hypothetical question for you... Should a receiver mounted on an antenna be lit up during an emissions test? The receiver down-converts the received signal?? Thanking you all in advance.. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; mailto:charles.gra...@echostar.com; %20 Email Alternate: chasgra...@ieee.org mailto:chasgra...@ieee.org
