[sdiy] Poor man's EMC testing?

[Jay Schwichtenberg]

I don't think that you'd have the bandwidth that you need unless you got a
lab scope. The high end scopes I work (not lab scopes but bench scopes) with
have 5X over sampling and go to 1 GHz. Even though they are suppose to work
at 1 GHz I find that after about 300 MHz signals aren't good enough (for me
at least) to do good measurements. Trouble shooting yes, detailed
measurements no.

The spectrum analyzers I've worked with do a down conversion and knock the
signal down to a reasonable freq for sampling. Then they sample both the I
and Q signals and do their stuff on that.

Jay S.

> -----Original Message-----
> From: cheater cheater [mailto:cheater00 at gmail.com]
> Sent: Wednesday, March 17, 2010 10:09 PM
> To: Jay Schwichtenberg
> Cc: synth diy
> Subject: Re: [sdiy] Poor man's EMC testing?
>
>
> Just a thought, but if you don't have a spectrum analyzer maybe you
> can use a digital oscilloscope with capture, and analyze the data in
> desktop software. I don't know how that would turn out, though.
>
> D.
>
> On Wed, Mar 17, 2010 at 04:19, Jay Schwichtenberg
> <jays at aracnet.com> wrote:
> > I had to do some of this stuff mid-90s. One thing we did was we
> went in and
> > got CE certification and not FCC. At the time CE was more
> stringent than FCC
> > so if you made it past that you got FCC for free. Might be
> something to look
> > into.
> >
> > We'd do our initial work in a chamber and once we passed that
> we'd do the
> > open field testing. It literally was open field testing. They
> had tents set
> > up in a gully in the mountains to avoid stray EMI. Still they'd
> have to run
> > a test multiple times if there was a cell phone operational on the main
> > road. The techs could tell real easy if it was a cell phone or
> our equipment
> > by the frequency of the signal.
> >
> > As mentioned finding someone that has the equipment and knows
> how to use it
> > would be the cheapest way of doing a preliminary test.
> >
> > Good luck
> > Jay S.
> >
> >
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>