[time-nuts] DDS'ery

[lists at lazygranch.com]

You did a good job just finding the title. Socrates search?

I looked at it in the flesh in the Terman library. I suppose the dissertation can be purchased. 

I left out hyperbolic functions. I'm not sure if it can compute logs. I had need once to compute a log and found an old paper from IBM for a log algorithm. 

We did a DTMF with a coordic. This was all part of a DSP based modem, unique for its time, routine to the point of boredom today. The DTMF accuracy was of course spot on. Basically once you have the algorithm in the box, you might as well use it, even if the quality is overkill. 

I don't have Marvin's Frerking's book on DSP comms because I left that field before it was published, but I am told it covers cordic and similar algorithms. If you google Marvin Frerking cordic, some of his book is digitized in google books. 

------Original Message------
From: Attila Kinali
To: lists at lazygranch.com
To: Discussion of precise time and frequencymeasurement
Subject: Re: [time-nuts] DDS'ery
Sent: Jun 20, 2011 2:35 PM

On Mon, 20 Jun 2011 20:26:46 +0000
lists at lazygranch.com wrote:

> With the coordic (yeah, sometimes cordic), you need to build it
> a few more bits wider than the DAC. Then it closely matches the lookup 
> table. One of the best references for the coordic I found was a PhD 
> dissertation at Stanford. The author's last name was Ahmed IIRC.

This seems to be "Signal processing algorithms and architectures" by
Hassan Masud Ahmed, 1982.

Unfortunately, my google skills fail me to locate a digital copy
of this dissertation. I'm even unable to locate a paper version
in any of the university libraries.

Does anyone have this as PS or PDF? 


			Attila Kinali

-- 
Why does it take years to find the answers to
the questions one should have asked long ago?