If anyone is really interested in an SDR WWVB receiver project, TAPR has
a fairly large quantity of boards left over from a previous project that
use a very high performance 192ksample sound card chip (AK5394) in a
carefully laid-out design with no filtering (I believe the inputs are
also DC coupled). The board also has a CPLD which might be repurposed
(don't know if it's big enough to be useful).
The downside is that the board talked directly to the application
software, so there are no OS-level drivers available.
We would love to find a use for these boards, and could probably make a
nice deal if someone wanted to use them in a project.
Here's a link to some information:
http://openhpsdr.org/wiki/index.php?title=JANUS
Contact me off-line if you're interested or have further questions.
John
----
On 8/6/2015 9:41 PM, Bob Camp wrote:
Hi
Well, at least *some* of the chips out there do not make it to 96 KHz when
sampling at 192 KHz. It’s
been a few years since I dug into them. Back then a chip that had an internal
filter that went to 96K
was very much the exception rather than the rule. If the only point of 192K is
getting to a 96K bandwidth,
a lot of the chip guys missed out on it ….
Bob
On Aug 6, 2015, at 6:24 AM, David G. McGaw <david.g.mc...@dartmouth.edu> wrote:
That is not true. If the converter is set to 192kHz sampling, the bandwidth
will be nearly 96kHz, typically at least 80kHz, not limited to 20kHz. That is
the POINT of 192kHz sampling.
David N1HAC
On 8/5/15 10:03 PM, Graham / KE9H wrote:
Scott:
You won't be able to use an off-the-shelf audio card, because they will have
filters that cut off just above human hearing limits, somewhere in the
mid 20 kHz range. I was referring to the data converter chips they use
on those high end cards. The circuit for ~80 kHz (Nyquist) low pass
filters
and antenna interface would likely be a custom card.
For the guys talking about the Tayloe receivers, the Tayloe front end is
just
a down converter to get the HF or VHF signals down into the range that WWVB
is already in. So to receive WWVB, you only need the backend of the Tayloe
receiver, ie., no Tayloe mixer required. Just the (audio) data converter
and the
DSP.
--- Graham / KE9H
==
On Wed, Aug 5, 2015 at 5:47 PM, Scott Newell <newell+timen...@n5tnl.com>
wrote:
At 12:40 PM 8/5/2015, Graham / KE9H wrote:
Content-Transfer-Encoding: 8bit
There are several high end audio Analog to Digital Data converters that
will clock at 192 kHz, ~23 bits ENOB, which puts a 60 kHz signal sweetly
in
the first Nyquist zone. Typical NF of the front end of the data converter
Any specific recommendations? I've seen the Asus Xonar U7 (USB) and Asus
Xonar D1 (PCI) mentioned on some of the SDR sites. (I'm running XP and
linux.)
--
newell
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