Message-ID: <4D41B0B8.9070205@freenet.de>
Date: Thu, 27 Jan 2011 18:51:52 +0100
From: wolf_dl4yhf <dl4yhf@freenet.de>
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References: <4D3FEDB4.25085.220078F8@jurgenb2.3sdesign.de> <4D404843.4060409@legal-medicine.de>
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Subject: Re: LF: Plot made in N.Germany until 0700z
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Hello Jurgen,

Just a thought... try to switch the various attenuator settings (in the 
Perseus sdr control panel) in and out, and watch the amplitudes 
(magnitudes) of all those peaks. When stepping the attenuator by 10 
(dB), but not all of those peaks change by *exactly* 10 dB, it's an 
overload / intermod problem somewhere. I don't know the inner workings 
of the Perseus FPGA, but if it uses integer values internally, the 
'overload' problem may even be a 16-bit integer overflow somewhere.
SL internally uses floating point numbers internally, which should have 
more than enough dynamic headroom.

Cheers,
    Wolf .


Am 26.01.2011 17:13, schrieb pws:
> Hi Jurgen,
>
> You wrote:
>> Last night I started SpecLab to plot 10-72 kHz
>>
>> Here is the result until 0800 local ( = 0700 ut)
>> http://dx.3sdesign.de/temp/Spectr-110126-0800_10-72kHz.jpg
>> ...
> Receiver kaputt?
>
> Please compare 16-26 by 36-46 kHz in that plot. Additionally there are some
> signals visible above 50 kHz never been observed by others.
>
> Gruss aus Kiel,
> Peter
>
>
>