[Elecraft] Measuring power output of an SSB transmitter

[Alan Bloom]

Actually, for a narrow-band signal, you only have to sample at twice the
BANDWIDTH, not twice the frequency.  So long as there are no interfering
signals around (reasonably accurate when measuring a transmitter),
so-called "undersampling" works fine so long as:

1.  The sample rate is more than twice the bandwidth.
2.  None of the harmonics (sample_rate/2) fall close to the signal.

Al N1AL


On Tue, 2008-04-29 at 11:05, Romanchik Dan wrote:
> Sampling at twice the bandwidth will allow you to accurately extract  
> frequency information about a signal, or if all you were viewing were  
> sine waves. To view the actual waveform, however, you really want to  
> sample at at least 4x or 5x the bandwidth, or, even better, 10x the  
> bandwidth.
> 
> 73!
> 
> Dan KB6NU
> ----------------------------------------------------------
> CW Geek and MI Affiliated Club Coordinator
> Read my ham radio blog at http://www.kb6nu.com
> LET'S GET MORE KIDS INTO HAM RADIO!
> 
> 
> 
> On Apr 29, 2008, at Apr 29, 1:32 PM, Stephen Prior wrote:
> 
> > On a related topic, does anyone have any experience of using the  
> > usb types
> > of 'oscilloscopes' which appear on eBay- dual channel 60MHz  
> > bandwidth and
> > 150Mb/s sampling rate?  It's a neat and cost-effective way of  
> > displaying the
> > transmitted waveform for those of us without desk/bench room for a  
> > 'proper'
> > scope.
> >
> > I've always been led to believe that sampling at twice the  
> > bandwidth is a
> > decent decent rule of thumb and this one is better than that.
> >
> > I'd be grateful for any advice from someone who has one.
> >
> > Thanks
> >
> > Stephen G4SJP
> >
> > KX-1, K2, K3 almost!
> >
> >
> >
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