While you do mention the screen room, a word of caution for using pre-amps on OATS. When there are strong ambients such as nearby TV and Radio stations, there are quite a bit of intermodulation products as well as "bleeding". I see that often and I sometimes have to switch between amp and no-amp to determine if the signal seen with the pre-amp is real. Another caution is when measuring signals near the noise floor and amplifying them does not give accurate levels. I have seen as much as a 10 dB error when you amplify signals near the floor level. Some amplifiers are better than others!
--- "Greilich, Jeff" <[email protected]> wrote: > > John, > > You hit it on the head. The reason for the first preamp is to overcome > line losses and the second preamp would be used if a spectrum analyzer > is being used in lieu of a CISPR Receiver. > > Regards, > > Jeff > > > -----Original Message----- > From: John Woodgate [mailto:[email protected]] > Sent: Thursday, February 28, 2002 2:03 AM > To: [email protected] > Subject: Re: SV: Screened Room Ambient Scans > > > > I read in !emc-pstc that [email protected] wrote (in <DCFCB38F97E9CF46 > [email protected]>) about 'SV: Screened Room Ambient > Scans', on Wed, 27 Feb 2002: > >May be you should consider a pre-amplifier. > > Is there any reason to use a preamplifier apart from the possibility > that its noise figure may be better than that of the spectrum analyser? > It seems unlikely that it would be much better than that of a CISPR > receiver. > > Or do you mean a preamplifier at the antenna, to send a larger signal to > the antenna cable and thus to the analyser or receiver? > -- > 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: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > 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: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > 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" ===== Best Regards Hans Mellberg Regulatory Compliance & EMC Design Services Consultant By the Pacific Coast next to Silicon Valley, Santa Cruz, CA, USA 408-507-9694 __________________________________________________ Do You Yahoo!? Yahoo! Sports - sign up for Fantasy Baseball http://sports.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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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"
