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

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Subject: Re: [CQ-Contest] SDR Mythbusters - ADC Overload myths debunked...
From: "Mark van Wijk, PA5MW" <pa5mw@home.nl>
Date: Mon, 9 Nov 2015 18:41:25 +0100
List-post: <cq-contest@contesting.com">mailto:cq-contest@contesting.com>
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




<snip>


K9YC wrote:

The Noise Power Ratio Test is especially problematic --

<snip>


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