wwv audio testing - NTP

This is a discussion on wwv audio testing - NTP ; Hi Folks--- If you've been trying to get the ntp audio code working, its handy to have a known source of audio available. There's a tool in the ntp distribution that works on solaris (I've tried it under solaris x86) ...

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Thread: wwv audio testing

  1. wwv audio testing


    Hi Folks---

    If you've been trying to get the ntp audio code working, its handy to have a
    known source of audio available. There's a tool in the ntp distribution that
    works on solaris (I've tried it under solaris x86) to do this. No port for
    linux or freebsd, yet, though, that I've seen.

    This afternoon I managed to get Colin Plum's wwv hack working ok under linux.
    I fixed a few bugs, and now it seems to happily generate a wwv signal out the
    sound card of my linux alsa setup. Feeding this into another linux host that
    is running the ntp audio code works nicely. The sending computer is locked to
    GPS via ntp, and the little audio tool ticks along just swell.

    I've added a paragraph about this on my PC gnu/linux and freebsd ntp server page:

    http://www.wraith.sf.ca.us/ntp/index.html#test-tones

    There's a link to the patched code on the site.

    If your audio setup works with this, then you should be able to get the IRIG
    or CHU audio going as well. I've configured up IRIG here, but I don't have
    a radio that is CHU capable so I haven't done that yet.

    The sound card part is still a bit tricky. Audio input seems to not always be well
    tested in the drivers.

    .../Steven

  2. Re: wwv audio testing

    Steven,

    The tool works for IRIG, too. The problem with the WWV generator is that
    there is no feedback loop correcting for the audio codec intrinsic
    frequency error. The only way to do this is looping the soundcard output
    to input and disciplining the generator to the system clock as
    maintained by NTP. Not really hard, but intricate.

    Dave

    rtxo wrote:
    >
    > Hi Folks---
    >
    > If you've been trying to get the ntp audio code working, its handy to
    > have a
    > known source of audio available. There's a tool in the ntp distribution
    > that
    > works on solaris (I've tried it under solaris x86) to do this. No port for
    > linux or freebsd, yet, though, that I've seen.
    >
    > This afternoon I managed to get Colin Plum's wwv hack working ok under
    > linux.
    > I fixed a few bugs, and now it seems to happily generate a wwv signal
    > out the
    > sound card of my linux alsa setup. Feeding this into another linux host
    > that
    > is running the ntp audio code works nicely. The sending computer is
    > locked to
    > GPS via ntp, and the little audio tool ticks along just swell.
    >
    > I've added a paragraph about this on my PC gnu/linux and freebsd ntp
    > server page:
    >
    > http://www.wraith.sf.ca.us/ntp/index.html#test-tones
    >
    > There's a link to the patched code on the site.
    >
    > If your audio setup works with this, then you should be able to get the
    > IRIG
    > or CHU audio going as well. I've configured up IRIG here, but I don't have
    > a radio that is CHU capable so I haven't done that yet.
    >
    > The sound card part is still a bit tricky. Audio input seems to not
    > always be well
    > tested in the drivers.
    >
    > ../Steven


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