Re: LRPT Laboratory Bandwidth testing


Patrick Lindecker
 

Hello Fred,

 

>Question, In the I/Q mode is the Global Level relevant?   It did not go above 2% for this pass.  I did not correct
>the RSP gain at all.

In principle, weak signal can pose a problem if the digital noise is relatively high. For example, I remember that for old 16 bits sound cards, only 13 or 14 bits could really be used. So in that case very weak signals were mixed with a drop of noise.

 

I have not tested my RSP1A but Multipsk only uses the first 8 bits of the 10 or 12 bits possible, so I suppose that these 8 bits are surely “clean”. 2% of level means that you work with about 2 bits. It’s not ideal but it is not so bad, seeing your nice images.

 

Under DOS, there were decoders working with one bit and they worked well…

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Fred Albertson
Envoyé : mardi 22 décembre 2020 14:22
À : multipsk@groups.io
Objet : [multipsk] LRPT Laboratory Bandwidth testing

 

Hi Patrick,

This morning, on a medium quality pass, I used the RSP with no filters or amps. Again I used the 120kHz filter which
does not seem to affect the picture quality at all.  One thing I note is that the picture lines are more consistent
between the frames.

Question, In the I/Q mode is the Global Level relevant?   It did not go above 2% for this pass.  I did not correct
the RSP gain at all.

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Great day,

Fred

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