[Elecraft] [K3] APF and Pitch

[Pierfrancesco Caci]

thanks Ron, I guess this relates to Q=f/deltaf ? Didn't even think of
this, and it's interesting that the effect is noticeable at these
frequencies. 

Pf



>>>>> "Ron" == Ron D'Eau Claire <ron at cobi.biz> writes:


    Ron> I believe that you'll find that is true of any filter. By cutting the tone
    Ron> frequency almost in half (800 to 440 Hz), you almost double the effective
    Ron> width of the passband. That leaves more room for the keying sidebands which
    Ron> means less "ringing" or stretching of the keying transitions.

    Ron> (I like lower frequency tones too.) 

    Ron> 73 Ron AC7AC

    Ron> -----Original Message-----
    Ron> From: elecraft-bounces at mailman.qth.net
    Ron> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Pierfrancesco Caci
    Ron> Sent: Sunday, May 12, 2013 1:25 AM
    Ron> To: elecraft at mailman.qth.net
    Ron> Subject: [Elecraft] [K3] APF and Pitch


    Ron> Someone mentioned that APF rings less when pitch tone is set to 440 Hz
    Ron> instead of 800 Hz. So, I'm trying and it indeed seems to ring less. 
    Ron> Anyone else hearing this?
    Ron> Is this some DSP effect or a psychoacustic effect? 

    Ron> Condition of test: 
    Ron> 200Hz 5-pole filter
    Ron> DSP BW 50Hz
    Ron> RF gain backed so that signal is barely audible with no APF RX Audio EQ
    Ron> bands 4 and 5 set to 0, all rest down -6

    Ron> Pf

    Ron> --
    Ron> Pierfrancesco Caci, ik5pvx


-- 
Pierfrancesco Caci, ik5pvx