[Elecraft] KX3 roofing filters

[Jim Dunstan]

At 03:30 PM 5/26/2011 -0700, you wrote:

>Jim Dunstan-2 wrote:
> >
> > My interpretation is that the "narrow roofing filter option" is variable
> > with 500, 1500, 2700, and 3800 hz steps that follow the DSP filter as it's
> > bandwidth is changed.
> >
>
>These filters are ahead of the DSP at baseband.  They protect the ADC from
>overload and should result in better Blocking Dynamic Range (BDR), which has
>been a weakness of most SDRs.
>
>73,  Bill

Hi,

Yes, that is what I understand.  I didn't mean that the filter comes after 
the DSP ... it comes before the DSP filter ... but it's bandwidth is 
adjusted according to the DSP bandwidth .... as the DSP bandwidth is 
changed the roofing filter will follow. The filter is at a vy low frequency 
prior to the ADC ... I am wondering what kind of filter it is as it 
certainly can't be a xtal filter at this vy low frequency .... has to be 
some kind of software controlled filter.

Jim, VE3CI