[Elecraft] CW filter and Roofing filter

[Fred Jensen]

On 6/24/2015 5:55 AM, Gee wrote:
> with any filter selected using the
> XFIL button on the K3, there is only ONE crystal IF filter in the
> signal path.

Correct

> In other words, there is no cascading or tail ending of
> the filters before and after the IF.

Semi-correct.  If by filter you mean crystal roofing filter, and if by 
IF you mean 1st IF [8 MHz], correct.  One roofing filter followed by 2nd 
IF filtering provided by the DSP.

  2) if I select a 400 Hz filter
> with the XFIL button then adjusting the DSP WIDTH control to any
> WIDER than 500 Hz is pointless.

Sort of.  The K3 will automatically select a roofing filter from 
whatever you have that is wider than what the DSP is set to ... if it can.

  3) can the DSP be bypassed to produce
> a purely analog demodulated audio to the speaker?

No.  Once the 15 KHz 2nd IF becomes number soup in the DSP, there are 
only two analog things left in the chain:  The AF amplifier and you. 
The DSP contains a lot more than just adjustable filtering, such as AGC 
and demodulation.

> It is interesting to note that
> there are new hams out there who have never listened to an analog
> receiver before.

True

 >It can be an eye opening experience!

Possibly, although I doubt most would find that.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015
- www.cqp.org