[CQ-Contest] SDR Mythbusters - ADC Overload myths debunked...

[Mark van Wijk, PA5MW]

The NPR test is flawed because of its reference MDS.



MDS is measured using a STEADY carrier.

As soon as you modulate a weak signal carrier, it  disappears in the band 
noise of most DSP based receivers where analog systems still offer a 
readable signal.

My measurements showed that analog receivers recover modulated signals at 
5 - 8 dB lower levels.

*****try measuring MDS with modulated testsignals for a change *****

(a simple dit-dit-dit-dit as used in a S/N test-mode will do already)



My conclusion:

the MDS reference as a static benchmark does not resemble any real-life 
situation.

The calculated NPR figure is thus flawed; it does not relate to any 
intelligent radio communication reception.

73 Mark, PA5MW




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K9YC wrote:

>The Noise Power Ratio Test is especially problematic --

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