Date: Fri, 16 Sep 2005 08:51:33 -0700 From: "Don" <[EMAIL PROTECTED]> Subject: Re: [Elecraft] Algorithm for Tuner To: "Bill Coleman" <[EMAIL PROTECTED]> Cc: elecraft@mailman.qth.net Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response
Bill, It's worse than that. Even with my reed relays (very fast compared to conventional relays) I have to allow 10 mS for them to settle and the A/D requires a millisecond or so to read the forward and reflected power. Don, Why not take an approach normal to the manual tuner. That is capacitance to mid scale and adjust L to best. Then adjust C up or down from midscale for min. ? Doing this with a possible repeat for missing the L value by +/- 1 has always yielded me good fast manual results on my old mfj tuners and doesn't require a tremendous number of iterations or complex programming. best regards, Charles wb5izd A reiterative multilevel slope-sensing algorithm using decreasing granularity* is the answer. I have been slowely creeping up on a satisfactory solution and, depending on distractions, hope to have a fairly fast autotuner in a week or so. Suggestions from the list have been very helpful. * my term ... don't try to look it up! ;) Don K7FJ > > On Sep 15, 2005, at 11:22 AM, Craig Rairdin wrote: > >> In this particular case, if you were to iterate over all possible >> combinations of L and C it's only necessary to store the best result so >> far >> and compare the current result to the best result. If the current result >> is >> better, it becomes the new best. Now you have no sorting at all and your >> time is order N instead of order N^2. > > The problem with the exhaustive search is there are 2^17 = 131,072 > combinations to try. (256 cap and inductor values, plus reversing the > whole L network) > > It takes a few ms for each relay to physically switch. If you can try 100 > combinations a second (10 ms), that's still about 20 minutes to try them > all. Even with 1 ms switching time, you're still looking at 2 minutes to > find a match. > > A tough problem. > > Bill Coleman, AA4LR, PP-ASEL Mail: [EMAIL PROTECTED] > Quote: "Not within a thousand years will man ever fly!" > -- Wilbur Wright, 1901 > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
