[hpsdr] "Taylor Corrected DDS"

[Robert McGwier]

John:

Your way will be faster,  smaller, and will have much poorer 
performance.    The 2^12 * 2^8  will be "secants"  connecting the 2^20 
points on the circle as defined by the trig identities and the two 
tables.  The 2^12 linear interpolation will simple yield secants between 
the 2^12 points in the first table.   The 2^12 * 2^8 will be an exact 
match to the correct complex numbers on all 2^20 points.  The linear 
interpolation way will NEVER be on the correct value between the 2^12 
original points.   This will have significantly higher total harmonic 
distortion, spurs, etc.

73's
Bob
N4HY



John B. Stephensen wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> A simpler and smaller mechanism is to do linear interpolation between the
> points in a sine table.
>
> 73,
>
> John
> KD6OZH
>
> ----- Original Message ----- 
> From: "Bob McGwier" <n4hy at idaccr.org>
> To: <hpsdr at hpsdr.org>
> Sent: Wednesday, June 14, 2006 18:04 UTC
> Subject: [hpsdr] "Taylor Corrected DDS"
>
>
>   

-- 
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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