Good Evening Steve, I cannot remember reading anything about the use of a noise generator for "tuning" filters, but back in the early '50s we used to use a noise generator plus spectrum analyser to align 30MHz IF strips used in radar receivers. Also during the design of filters etc. We simply cranked up the noise generator that was used for noise figure measurements, and the technique was very useful also when designing antenna systems. But I have no idea from whence the concept came.
But KM4DT and Tom ARE to be applauded for letting us know about Spectrogram in this day of the PC, which as I see it gives us all a low (zero) cost LF spectrum analyser. The mind boggles at the number of possible applications! 73, Geoff GM4ESD ----- Original Message ----- From: "Steven Gibbs" <[EMAIL PROTECTED]> To: <elecraft@mailman.qth.net> Sent: Sunday, January 16, 2005 4:35 PM Subject: Re: [Elecraft] Noise gen / Spectrogram--who invented? > Tom Hammond wrote: > > I was NOT the one to find and > > suggest the use of Spectrogram... > > > In September of 1999, Alan Childress, KM4DT, first brought our > > attention to the freeware program Spectrogram, and he first > > mentioned its use in aligning the K2's CW filters. Because it > > was such a radical concept, > > Yes, thanks Tom for setting out the facts, and our thanks to KM4DT. > > Do Elecraft listers know of earlier mention of this technique in > the amateur or professional literature? > > If not, then KM4DT deserves an even BIGGER accolade. In any case, > many will acknowledge that making filter & BFO adjustent so > straightforward has contributed greatly to the K2's success. > > 73, Steve GU3MBS. > _______________________________________________ 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
