Re: K3: course wanted: Panadaptor 101

Posted by N8LP on May 24, 2007; 3:56pm
URL: http://elecraft.85.s1.nabble.com/K3-course-wanted-Panadaptor-101-tp447983p447990.html

I didn't... and then I did... all in the course of a few minutes ;-)  It
pays to put all your reasoning in your posts, so that you can convince
yourself all over again that what you're saying makes sense. I forgot
that and paid the price. Please refer to my original post and ignore the
revision.

Bottom line is that if you don't mind being tied to a PC, and being
limited to BW in the 80-90 kHz range (or 160-180 kHz range, depending on
the sampling and filtering quality in the sound card), then a softrock
approach can be a reasonable alternative... although far from cheap if
you want top performance.

One advantage is that for casual listening, you have a second (or third)
receiver.

Larry N8LP



Jack Smith wrote:

> Yes, of course. I had forgotten it was an I/Q demodulator.
>
> Jack K8ZOA
>
>
> [hidden email] wrote:
>>> A 192 kb/s sample rate gives you a usable bandwidth (Nyquist =
>>> sample rate/2) of 96 KHz, assuming a brick-wall anti-alias filter.
>>> More likely, the usable bandwidth will be about 80 KHz with a
>>> practical anti-alias filter.
>>>    
>>
>> Make that 80 or so kHz lower side band and 80 or so kHz upper side
>> band, and then you have 160 or so kHz total, without breaking
>> Nyquist. This assumes that you have I & Q signals.
>>
>> This is what Flex-Radio does.
>>
>> See:
>> http://www.flex-radio.com/Data/Doc/qex1.pdf
>> http://www.flex-radio.com/Data/Doc/qex2.pdf
>> http://www.flex-radio.com/Data/Doc/qex3.pdf
>> http://www.flex-radio.com/Data/Doc/qex4.pdf
>> vy 73 de toby
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