[hpsdr] new DDS

[KD5NWA]

Some serious limitations on the technology;

1. The output frequency must not be any lower than 20% of the 
reference oscillator.
2. The compensation required is dependent on the chip, it varies from 
unit to unit so much that the values of one chip can not be used on 
another chip.

Sounds like it will be of limited use in a environment where the 
frequency varies all over creation.


At 02:03 PM 5/27/2006, Robert McGwier wrote:
>***** High Performance Software Defined Radio Discussion List *****
>
>Leon Heller wrote:
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> > http://www.analog.com/UploadedFiles/Data_Sheets/610141489AD9911_0.pdf
> >
> > Interesting feature is 'SpurKiller'technology.
> >
> > 73, Leon
> >
>This is bloody brilliant.  Many of us have proposed blind deconvolution
>and of course, this is insanity compared to this.  The location of these
>spurs has a mathematical, closed form description.  Given the phase in
>the accumulator and the frequency,  you can mathematically compute the
>frequency, phase, and amplitude of these spurs to high accuracy.  They
>have chosen to take N of them (it looks like up to 3), invert them and
>add them to the output effectively suppressing the 3 worst (if I read
>this correctly).  To capture that in the hardware itself is a very nice
>piece of work.   I have not taken the time to see if this part can be
>sync'd or if they are introducing a I/Q version.
>
>Bob
>
>
> > --
> > Leon Heller, G1HSM
> > leon.heller at bulldoghome.com
> > http://www.geocities.com/leon_heller
> >
>
>
>--
>AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats,
>NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman
>Laziness is the number one inspiration for ingenuity.  Guilty as charged!
>
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Cecil Bayona
KD5NWA
www.qrpradio.com

"Windows the worlds most successful software virus" 


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