Hi Pf, Most tone modes operate at an offset from carrier frequency, so that the audio frequencies of interest are more or less cenetered in the filter passband. I believe the JTx modes are already in the 1200 to 1500 Hz range so no offset is required.
The crystal filter being used only restricts the bandwidth of the RX chain (1st IF). The DSP imposes its own audio filtering on the baseband, and that's what you're seeing as rolloff below ~300 and above ~3500 Hz. 73, matt W6NIA On Sun, 23 Aug 2015 19:03:21 +0200, you wrote: > >Hello, >I'm dabbling with wsjtx, and I see that my rx audio has some definite roll >off at <300 Hz and >3500 Hz. Selected filter is the 12 kHz one, and >width is set to 4 kHz. Audio soundcard is the Numark studio-io, but I >also saw this with an el-cheapo adapter. >Also, I see the same roll-off in fldigi, so the final application should >not matter. >Am I doing something wrong? What should be the audio passband available >at line out connector? > >Thanks > >Pf Matt Zilmer, W6NIA -- "Always store beer in a dark place." -R. Heinlein ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
