[Elecraft] SDR filter improvement

[William Abernathy]

Thanks. Have not got the K4 yet. I may punt and go for a Icom 7610 as the K4 is not coming for a very long while. 

Regards,

William Abernathy
(513) 368-8276
wabernat at gmail.com


> On Jul 1, 2021, at 6:11 PM, Hal Massey <haljr.massey at gmail.com> wrote:
> 
> 
> Try the receive equalizer… kill the high frequencies…
> 
>>> On Jul 1, 2021, at 4:07 PM, William Abernathy <wabernat at gmail.com> wrote:
>>> 
>> Thanks Hal. 
>> 
>> Maybe the K4 will let me turn down the volume on the high pitch qrm. Thank that would work?
>> 
>> I am familiar with filtering but for light. I used to sell machine vision. Erode, dilate, clip and stretch were my favorite filters. 
>> 
>> Regards,
>> 
>> William Abernathy
>> (513) 368-8276
>> wabernat at gmail.com
>> 
>> 
>>>> On Jul 1, 2021, at 12:01 PM, Hal Massey <haljr.massey at gmail.com> wrote:
>>>> 
>>> You are welcome. There are some websites you can go to. They let you build your own digital filters and see what they are like. Meaning you can listen to what you build ton your computer speakers! 
>>> 
>>> They have things like digital audio generators so you can run test signals through your digital filter. You can push a 1,000 Hertz sine wave thru your filter and listen to the result, for example. 
>>> 
>>> They also have common filters pre-built that you can play with. When I say prebuilt I mean all the usual ham filters like low pass, high pass, bandpass, etc. These sites are a lot of fun if you want to learn and play around a bit at the same time. 
>>> 
>>> Also, YouTube has some great material at the introductory level these days. 
>>> 
>>> 
>>> 73
>>> -Hal
>>> 
>>> 
>>> 
>>>> On Jul 1, 2021, at 06:01, William Abernathy <wabernat at gmail.com> wrote:
>>>> 
>>>> Hal,
>>>> Thanks. I think the book is probably over my head. 
>>>> 
>>>> I do hope for more improvements. Still can hear the QRM ringing in my head after Field Day
>>>> 
>>>> 73
>>>> 
>>>> William Abernathy
>>>> 
>>>> 
>>>>>> On Jun 30, 2021, at 10:44 PM, Hal Massey <haljr.massey at gmail.com> wrote:
>>>>>> 
>>>>> Digital Signal Processing is a field all unto itself. They are definitely *not* emulating mechanical filters. If they were they would be ringing like a mechanical filter. A great text is, "Discrete-Time Signal Processing by A. V. Oppenheim and R. W. Schafer.
>>>>> 
>>>>> This is good news because we have not plumbed the depths of what can and can’t be done with DSP yet. 
>>>>> 
>>>>> 
>>>>>> On Jun 30, 2021, at 13:05, William Abernathy <wabernat at gmail.com> wrote:
>>>>>> 
>>>>>> Hi,
>>>>>> Seems that SDR radios have software emulation of mechanical filters like
>>>>>> noise reduction.  Do you think the future holds new filters written in
>>>>>> software?  I would like a subtraction filter that pulls out the guy 2 KC's
>>>>>> away.  Maybe the 2nd receiver could be tuned in on the station that needs
>>>>>> to be subtracted from the primary.
>>>>>> 
>>>>>> What do you think?
>>>>>> 
>>>>>> Wiliam
>>>>>> 
>>>>>> -- 
>>>>>> *William Abernathy*
>>>>>> *AA8XX at arrl.net <AA8XX at arrl.net>*
>>>>>> *AA8XX*
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>>>>> 
>>>