On 4/13/2013 5:09 PM, Cady, Fred wrote:
The roofing filter is actually at AF ahead of AF amplification and A/D. So basically it is roofing for the DSP. Pretty amazing.
OK, makes sense. One thinks [well, at least I do] that roofing filters are at the 1st IF, if the 1st IF is baseband then it's there I guess.
The term "Roofing Filter" seems to have sprung [that could be "sprang", spellcheck is no help here] up in the 90's. I didn't realize it was originally for the up-conversion schemes of many of the Japanese radios to protect the mixer. Makes sense though.
I have the "stock" filters in my K3, I now have only one local who could overload the mixer, and it all just works fine.
73, Fred K6DGW - Northern California Contest Club - CU in the 2013 Cal QSO Party 5-6 Oct 2013 - www.cqp.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
