[time-nuts] What's available in the way of DSP for new WWVB?

[paul swed]

Graham take a look earlier in the thread there are details about the
teensy. There is actually a lot of hardware out there today for little
money. Thats what makes the SDR DSP approach interesting and for me at
least the next thing to take a run at.
Regards
Paul
WB8TSL

On Tue, Oct 13, 2020 at 10:31 AM Graham / KE9H <ke9h.graham at gmail.com>
wrote:

> There are inexpensive CODECs or A-->D converters that are designed for
> audio, that can be clocked up to 192 ksps or 200 ksps with 24 bit
> resolution. (Typically 18 or 19 effective bits, 3.0 V p-to-p full scale)
> They have built in Nyquist filters that scale with the sampling frequency,
> so a Nyquist frequency of 100 kHz is very comfortable for receiving a 60
> kHz signal. They use standard I2S audio interface, although other
> interfaces are typically options.
>
> After that it is SMOP, as they say. (Simple Matter Of Programming).  :-)
>
> --- Graham
>
> ==
>
>
> On Fri, Oct 9, 2020 at 12:58 PM paul swed <paulswedb at gmail.com> wrote:
>
> > after the bpsk is removed true. I have done that. A simple RC filter and
> a
> > 100K over 50ohm divider to get the signal to a reasonable level. Add a
> > coupling cap because all of the old receivers output a preamp voltage.
> >
> > On Fri, Oct 9, 2020 at 11:35 AM Bob kb8tq <kb8tq at n1k.org> wrote:
> >
> > > Hi
> > >
> > > For a full setup, you could do it a lot of ways. A setup of:
> > >
> > > Antenna -> front end -> ADC -> MCU -> D/A would be one approach.
> Various
> > > bits like a local clock also would get into the design. There are
> *many*
> > > other
> > > approaches.
> > >
> > > ==========
> > >
> > > There are a lot of D/A’s that will clock in the 100’s of KHz range. If
> > you
> > > are only
> > > trying to come up with an analog of a WWVB signal the “10 bit” D/A’s
> > found
> > > in
> > > some MCU’s would do the trick. In the setup above, the ADC would likely
> > be
> > > harder to come up with than the DAC.
> > >
> > > Since you are only trying to come up with a carrier, the need for a D/A
> > is
> > > not
> > > an absolute one. Taking a square wave of some sort and filtering it a
> bit
> > > would
> > > be adequate to drive most of these old WWVB receivers.
> > >
> > > Bob
> > >
> > > > On Oct 8, 2020, at 11:42 PM, Hal Murray <hmurray at megapathdsl.net>
> > wrote:
> > > >
> > > >
> > > > I assume it needs an antenna, front end, and D/A.
> > > >
> > > > What's available in the way of D/A that's good for 60KHz?  Is the
> > > problem
> > > > easier if the D/A box has external clocking?
> > > >
> > > > --
> > > > These are my opinions.  I hate spam.
> > > >
> > > >
> > > >
> > > >
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