K3S Filter Shape Factor

[ab2cj]

All:

Where can one find filter shape factor specifications for Elecraft K3S
filters?

Thanks, Tony

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[Don Wilhelm]

Tony,

The filter shape factor is not stated, but there are filter plots on the
Elecraft website.

The filer shape factor for the roofing filters is not critical as it is
in an analog receiver.  In the K3/K3S, the final filter shape and shape
factor is determined by the DSP filters which follow - the DSP filters
have a very steep slope.

73,
Don W3FPR

On 3/20/2019 6:09 PM, ab2cj wrote:
> All:
>
> Where can one find filter shape factor specifications for Elecraft K3S
> filters?
>
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[Robert Sands]

I thought the shape factor of the 2.8kHz filter was 1.5 to 1 which is
impressive up front with good deep out of band pass rejection in excess of
70 dB. The DSP adds the final shaping to the signal that exceeds the
roofing filter spec and is therefore the most effective source of final
rejection. One observation I have made is that the DSP efficiency is better
when I use the 2.1 or 1.8 roofing filters which suggests that the
selectivity of the roofing filters is worth quite a bit in the mix. Is this
a fair analysis? MD here not EE.
Bob
K7VO

On Wed, Mar 20, 2019, 3:19 PM Don Wilhelm <[hidden email]> wrote:

> Tony,
>
> The filter shape factor is not stated, but there are filter plots on the
> Elecraft website.
>
> The filer shape factor for the roofing filters is not critical as it is
> in an analog receiver.  In the K3/K3S, the final filter shape and shape
> factor is determined by the DSP filters which follow - the DSP filters
> have a very steep slope.
>
> 73,
> Don W3FPR
>
> On 3/20/2019 6:09 PM, ab2cj wrote:
> > All:
> >
> > Where can one find filter shape factor specifications for Elecraft K3S
> > filters?
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
>

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[ab2cj]

All:

Thanks to everyone who responded to my question regarding crystal filter
shape factors for the K3S. The plots shown on the Elecraft website are a
bit fuzzy for my eyes, but I did find the list shown below from a post
in 2008.

I'm assuming the shape factors are the same for the current batch of
filters?

Tony

Filter  BW(-6dB)     Shape Factor
  200     224             4.0
  250     370             2.1
  400     435             2.1
  500     565             3.1
1000    1063             1.6
1800    1913             1.5
2700    2910             2.9
2800    2888             1.6
6000    6125             1.5



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[Nr4c]

Note that some of those filters are no longer available and new ones replace them.

Sent from my iPhone
...nr4c. bill

> On Mar 24, 2019, at 4:37 PM, ab2cj <[hidden email]> wrote:
>
> All:
>
> Thanks to everyone who responded to my question regarding crystal filter shape factors for the K3S. The plots shown on the Elecraft website are a bit fuzzy for my eyes, but I did find the list shown below from a post in 2008.
>
> I'm assuming the shape factors are the same for the current batch of filters?
>
> Tony
>
> Filter  BW(-6dB)     Shape Factor
> 200     224             4.0
> 250     370             2.1
> 400     435             2.1
> 500     565             3.1
> 1000    1063             1.6
> 1800    1913             1.5
> 2700    2910             2.9
> 2800    2888             1.6
> 6000    6125             1.5
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Please help support this email list: http://www.qsl.net/donate.html

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