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DL4YHF@aol.com wrote:
<blockquote TYPE=CITE><font face="arial,helvetica"><font size=-1>Hi Sandy,</font></font>
<p><font face="arial,helvetica"><font size=-1>from own experiments with
several soundcards I found only marginal differences as long as simple
waterfall display is concerned - so I confirm Alberto's comments.</font></font>
<br><font face="arial,helvetica"><font size=-1> (Instead of
a bit more dynamic range, I would love to have</font></font>
<br><font face="arial,helvetica"><font size=-1> a soundcard
with two DC-coupled inputs,</font></font>
<br><font face="arial,helvetica"><font size=-1> for I/Q
processing as last stage of a digital receiver</font></font>
<br><font face="arial,helvetica"><font size=-1> with
simple but good analog frontend).</font></font>
<p><font face="arial,helvetica"><font size=-1>A problem with audio cards
on the mainboard is that they often catch noise from the digital components
on the board. This can be very annoying, because sometimes the noise appears
like "interesting looking" noise on the waterfall (water on the mills of
the anti-soundcard fraction again ;-).</font></font>
<br><font face="arial,helvetica"><font size=-1>On the other hand, if the
soundcard "noise" is mostly random type, it is effectively reduced by the
narrow-band gain of the FFT. So, for high frequency resolution, the usable
dynamic range for a waterfall display often exceeds 120 dB (more than the
dynamic range of a 16 bit ADC !).</font></font>
<p><font face="arial,helvetica"><font size=-1>----</font></font>
<br><font face="arial,helvetica"><font size=-1>Related topic: I bought
some a low-cost PIC with 10-bit ADC (PIC16F870) recently, planning to connect
it to the serial interface as replacement for my laptop's audio device
(which only has a lousy *mono* MIC input). Has anyone on the group ever
tried to use this PIC for weak-signal work and check the ADC's performance,
compared to a soundcard ?</font></font>
<br>
<br>
<p><font face="arial,helvetica"><font size=-1>Regards,</font></font>
<br><font face="arial,helvetica"><font size=-1>Wolf DL4YHF</font></font>
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