From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f43.google.com (mail-yw0-f43.google.com [209.85.213.43]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id DD1C120069D for ; Wed, 14 Mar 2012 05:44:01 -0700 (PDT) Received: by yhkk6 with SMTP id k6so2778809yhk.16 for ; Wed, 14 Mar 2012 05:44:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=vRUxzl0DvFvALB7S086pM+r/Rt05CzMNyenzRVFc83g=; b=V6q/IdV7Iha53shJ2SmIzA0TpLfT6WZahWX2/RUkIrq7lt6OWoGM5N4GGPrK49ul8q ptjSRkyYBKddRTAwCBdLgOWS/wCuotuqshUa5HS/9GnklfUdXqWxlmKb4G3zzGQxTuAn m56reivTshi3JAWnlw4vqPHDkGmo6XRDbjp9H6jrsuJ0LeTsMlrVpN0I9M3elDVl0vmi //CA4YdL3hyOOKzzcJgzorRmUpJdly8sFlqN1bC+CqBRUN+8filz/TRFIFn2i59BJhx9 Iw3Kd9gPT8ODjDka5tOM85lsMGc8MPaY0zw4devtmtpjmGa3RdGe9AZcIjjNCKLz8Dvt ChyQ== MIME-Version: 1.0 Received: by 10.60.4.105 with SMTP id j9mr3043537oej.29.1331729040791; Wed, 14 Mar 2012 05:44:00 -0700 (PDT) Received: by 10.182.68.164 with HTTP; Wed, 14 Mar 2012 05:44:00 -0700 (PDT) Received: by 10.182.68.164 with HTTP; Wed, 14 Mar 2012 05:44:00 -0700 (PDT) In-Reply-To: <20120314043258.GA26308@thyrsus.com> References: <20120313230612.GA24800@thyrsus.com> <4F5FF42B.9060900@c3energy.com> <20120314043258.GA26308@thyrsus.com> Date: Wed, 14 Mar 2012 08:44:00 -0400 Message-ID: From: tz To: esr@thyrsus.com Content-Type: multipart/alternative; boundary=e89a8fb1f97a69d88704bb335404 Cc: thumbgps-devel@lists.bufferbloat.net Subject: Re: [Thumbgps-devel] Project clarification X-BeenThere: thumbgps-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Mar 2012 12:44:02 -0000 --e89a8fb1f97a69d88704bb335404 Content-Type: text/plain; charset=ISO-8859-1 The FTDI using CTS is showing a 1mS at most jitter with my venus 638 pps signal in my userland tests. The start bit offset is worse but the jitter seems similar. On Mar 14, 2012 12:32 AM, "Eric S. Raymond" wrote: > Dave Taht : > > So < 5ms would be the outside goal, and anything less than that - so > > long as it can be thoroughly catagorized - is a bonus. > > Yeah, that's *exactly* how I figure it, too, Nyquist's Theorem and all. > I set 1ms as a goal because the ZTI dongle does that and I think I > know how (jacking USB polling frequency to max), but you're right - for the > delay tomography we can live with anything < 5ms. > -- > Eric S. Raymond > _______________________________________________ > Thumbgps-devel mailing list > Thumbgps-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/thumbgps-devel > --e89a8fb1f97a69d88704bb335404 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

The FTDI using CTS is showing a 1mS at most jitter with my venus 638 pps= signal in my userland tests.=A0 The start bit offset is worse but the jitt= er seems similar.

On Mar 14, 2012 12:32 AM, "Eric S. Raymond&= quot; <esr@thyrsus.com> wrote:=
Dave Taht <dave.taht@gmail.com>:
> So < 5ms would be the outside goal, and anything less than that - s= o
> long as it can be thoroughly catagorized - is a bonus.

Yeah, that's *exactly* how I figure it, too, Nyquist's Theorem and = all.
I set 1ms as a goal because the ZTI dongle does that and I think I
know how (jacking USB polling frequency to max), but you're right - for= the
delay tomography we can live with anything < 5ms.
--
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0<a href=3D"http://www.catb.org/~esr/">Eric= S. Raymond</a>
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