Correct, CORDIC doesn't require a multiplier, only adds and shifts. That's the whole idea.
-- john, KE5FX > -----Original Message----- > From: [email protected] [mailto:time-nuts- > [email protected]] On Behalf Of [email protected] > Sent: Monday, June 20, 2011 5:24 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] DDS'ery > > I don't have the algorithm in front of me, but I don't recall any > multiplication, just addition and magnitude comparison. > -----Original Message----- > From: Jim Lux <[email protected]> > Sender: [email protected] > Date: Mon, 20 Jun 2011 17:14:44 > To: Discussion of precise time and frequency measurement<time- > [email protected]> > Reply-To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] DDS'ery > > On 6/20/11 12:17 PM, [email protected] 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 > very attractive. > > 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. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
