jimlux at earthlink.net
Tue Jun 21 00:14:44 UTC 2011
On 6/20/11 12:17 PM, lists at lazygranch.com wrote:
> Just a FYI, you don't have to use sine lookup tables. You can generate sine and cosine on the fly with a coordic. Perhaps not easy at RF speed, but very common in audio DSP.
It's a tradeoff.. To do CORDIC you need four multiplies and 2 adds,
which might be a lot of gates, if you have a fair number of bits,
compared to an adder and some lookup tables.
If you have a fast multiply instruction on a processor, then CORDIC gets
The other problem with CORDIC is that roundoff errors accumulate, the
longer you run the generator for, because it's basically a difference
equation/numerical integration sort of scheme.
That said, some of AD's latest DDSes use a monolithic CORDIC generator.
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