> It turns out you need a high end sound card for SDR.
High end in reality being only in the $150-200 range. And for
undoubtedly less $'s in the future.
> That other company found out one they were suggesting be
> used had one second
> TR time! No fast breakin possible! For most public sound
> card uses, the
> issues of turn around time are not an issue. But, for
> radio use, they can be killers.
Yepp that was kind of a bummer. But not really a big deal
though, give that Audigy 2 ZS card to the kids or grandkids
to use in their PC's for games. In any case it was only $100
or so poor choice, not all that big of a mistake $ wise. You
just swap it out and move on. And to put it into perspective
that card was less expensive than the typical Xtal filter
that you aren't as likely to be able to give your kids or
grandkids. FWIW that card does work quite well for the more
mundane ham radio "sound card" program use. I even used it
initially for my Corsair II DSP IF experiments with good
results.
And yes fast break-in CW does continue to be a challenge.
> The same could be true for the external computer. Windows
> after all, is not
> a real time operating system. Ie, it is not good for
> interrupt driven
> program needs such as Analog to Digital data conversion, in
> our some 35 years of working with such data.
I always had concerns about this too. Based on what I see
here it isn't the raw CPU speed that is the limiting issue,
it is the mathematically realities of the number of sample
bits taken together and processed as a group; and the
sampling rate for those samples that ultimately defines the
overall latency. This value of latency sets the max possible
speed limits for fast break-in CW as well.
I'm also quite pleased with how well even programmatically
bloated Windows XP works for this kind of task, just need to
throw enough CPU horsepower at it (only a $500 PC - new). By
doing so I can't say that I have ever seen any issues related
to HW/SW interrupts. That said a real-time OS would be a
better way to go for this kind of task.
Duane
N9DG
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