RE: Difference between Receivers and Spectrum Analyzers
Muriel: The biggest difference is the first stage of the spectrum analyzer. The typical SA presents the signal (possibly through a bandpass filter and attenuators) to the first stage mixer. A receiver typically has a tuned RF section, which improves selectivity. A SA thus has a higher noise figure, and it is more vulnerable to overload and mixer burn-out. Now, if your SA has a tunable pre-selector, it starts to look a lot like a receiver. And, if your receiver can be swept in frequency, it begins to look like a SA. Modern SA's and receivers are not all that different in performance. More importance is being given to processing beyond the RF/IF signal chain, and BOTH now look more like computers than anything else. 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: Muriel Bittencourt de Liz [mailto:mur...@eel.ufsc.br] Sent: Wednesday, September 25, 2002 11:51 AM To: Lista de EMC da IEEE Subject: Difference between Receivers and Spectrum Analyzers Hello Group, For EMC measurements (conducted and radiated emissions), electromagnetic fields measurements (via antennas), what is the difference between using a EMI Receiver or a Spectrum Analyzer?? Some guesses that I've been thinking are: - The Receiver is more accurate than the Spectrum Analyzer, so it is more suitable for EMC measurements that aim to respect the EMC standards. - For measuring electromagnetic fields (eg electric field) for safety (human safety standards for man-made electromagnetic fields, like ICNIRP) the Receiver is suitable because it can give an accurate value to a particular frequency that is being studied. - The spectrum analyzer is qualitative, i.e. it gives an idea of how the spectra measured is distributed in the frequency range. The receiver is quantitative, i.e. it gives accurate amplitude for each frequency swept. Well, I think this subject is very controversial, and it will generate a lot of discussions, that will be good for us all. Best Regards, Muriel B. de Liz --- 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: Difference between Receivers and Spectrum Analyzers
The lines between spectrum analyzers and receivers have grown very fuzzy, but in the old days the biggest difference was that a receiver had a narrow band tuned front end and an S.A. had a broadband one. This makes the S.A. more susceptible to out of band interference. I certainly wouldn't say that an S.A. is only a qualitative device. Regards, Brent DeWitt --- 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: Difference between Receivers and Spectrum Analyzers
One needs to distinguish between general purpose spectrum analyzers and those which have been designed for EMC measurements. A general purpose spectrum analyzer will probably not have the impulse bandwidths of the IF filters characterized, may not have the correct IF bandwidths, will not have a quasi-peak adapter, and may have problems correctly displaying impulsive noise. Inexpensive spectrum analyzers can have accuracy problems in both frequency and amplitude. I have not worked with measuring receivers, so I cannot compare them to spectrum analyzers designed for EMC work. Presumably, the accuracy of EMC spectrum analyzers is comparable to measuring receivers, or else they would not be competitive in the market. They must be accurate enough to be quantitative along with their qualitative abilities. Modern EMC spectrum analyzers can be tuned as quickly and accurately as a measuring receiver. But I do like having an EMC spectrum analyzer. One can watch it sweep and display emissions as a function of frequency. And if there is an emissions problem, one can use it as a (surprise!) spectrum analyzer to help solve it. Don Borowski Schweitzer Engineering Labs Pullman, WA Muriel Bittencourt de Liz mur...@eel.ufsc.br on 09/25/2002 11:51:00 AM Please respond to Muriel Bittencourt de Liz mur...@eel.ufsc.br To: Lista de EMC da IEEE emc-p...@ieee.org cc:(bcc: Don Borowski/SEL) Subject: Difference between Receivers and Spectrum Analyzers Hello Group, For EMC measurements (conducted and radiated emissions), electromagnetic fields measurements (via antennas), what is the difference between using a EMI Receiver or a Spectrum Analyzer?? Some guesses that I've been thinking are: - The Receiver is more accurate than the Spectrum Analyzer, so it is more suitable for EMC measurements that aim to respect the EMC standards. - For measuring electromagnetic fields (eg electric field) for safety (human safety standards for man-made electromagnetic fields, like ICNIRP) the Receiver is suitable because it can give an accurate value to a particular frequency that is being studied. - The spectrum analyzer is qualitative, i.e. it gives an idea of how the spectra measured is distributed in the frequency range. The receiver is quantitative, i.e. it gives accurate amplitude for each frequency swept. Well, I think this subject is very controversial, and it will generate a lot of discussions, that will be good for us all. Best Regards, Muriel B. de Liz --- 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 e-mail may contain SEL confidential information. The opinions expressed are not necessarily those of SEL. Any unauthorized disclosure, distribution or other use is prohibited. If you received this e-mail in error, please notify the sender, permanently delete it, and destroy any printout. Thank you. --- 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: Difference between Receivers and Spectrum Analyzers
Receivers have better dynamic range in the presence of strong signals because they have a tuned front end. A receiver can get better frequency accuracy on a wide sweep because there is no quantization error (the frequency resolution is NOT limited by the span divided by some number of bins per sweep). A receiver is normally calibrated over its entire frequency range (often using an impulse generator). That technique is unavailable with a wide-open spectrum analyzer. Often a spectrum analyzer is calibrated at a single frequency. Having said these things does not mean an expensive receiver is always better than a spectrum analyzer. If I am making measurements in a shield room and I need 1% frequency accuracy a spectrum analyzer will do just fine. I think that both a spectrum analyzer and an EMI receiver are way more instrument than you need to measure safety-related field intensities. The levels you are trying to measure are such that you would not need the sensitivity of either of these instruments, and the frequency resolution of even the spectrum analyzer is much better than needed. I realize that you will use these devices because they are around, but if I were interested in safety-related field intensities from an emitter such as a microwave oven or a cell phone a frequency counter and a power density probe would work just fine. is NOT on 9/25/02 2:51 PM, Muriel Bittencourt de Liz at mur...@eel.ufsc.br wrote: Hello Group, For EMC measurements (conducted and radiated emissions), electromagnetic fields measurements (via antennas), what is the difference between using a EMI Receiver or a Spectrum Analyzer?? Some guesses that I've been thinking are: - The Receiver is more accurate than the Spectrum Analyzer, so it is more suitable for EMC measurements that aim to respect the EMC standards. - For measuring electromagnetic fields (eg electric field) for safety (human safety standards for man-made electromagnetic fields, like ICNIRP) the Receiver is suitable because it can give an accurate value to a particular frequency that is being studied. - The spectrum analyzer is qualitative, i.e. it gives an idea of how the spectra measured is distributed in the frequency range. The receiver is quantitative, i.e. it gives accurate amplitude for each frequency swept. Well, I think this subject is very controversial, and it will generate a lot of discussions, that will be good for us all. Best Regards, Muriel B. de Liz --- 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 -- Ken Javor EMC Compliance Huntsville, Alabama 256/650-5261 --- 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
