On Dec 3, 2010, at 12/3 6:44 AM, Jan Erik Holm wrote: > So now we have a 2 ms claim for the K3. I know I measured it to 5 ms > but this was something like 2 years ago. > > What is it? Can Elecraft please tell.
Quite possibly the waveshaping is done by an FIR window. So the design parameter may not be directly comparable to the risetime of a first order IIR. (I hope Elecraft didn't take a shortcut and used IIR waveshaping!) You can of course use the 10% to 90% points as the equivalent risetime even for an FIR waveshaping, but there are subtle difference from the "risetime" compared to a typical RC filter, especially when the "tail" of the impulse of the FIR is very different from a decaying exponential. What I'm trying to say is that "2 msec" for one waveshape can produce vastly different spectrum from "2 msec" of a different waveshape when the standard of measurement is 10% to 90%. The portions between 0% to 10% and between 90% to 100% of the leading and trailing edges of a pulse are probably more important that what it is doing between 10% and 90%, which is usually a smooth function. If hams apply a frequency domain criterion (like, say, -6 dB and -60 dB points in the spectrum envelope of a sequence of dits) instead of a single number such as "risetime," we probably can more easily decide which rigs are problematical in regards to keyclicks. 73 Chen, W7AY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
