[time-nuts] NTP/1-PPS/RS232 question

Chris Albertson albertson.chris at gmail.com
Sun Sep 8 23:17:05 UTC 2013


Yes, 100 mega seconds.  It works out to about three years.  So you
need even more gates for the delay

On Sun, Sep 8, 2013 at 3:45 PM, Mark C. Stephens <marks at non-stop.com.au> wrote:
> Don't forget Hal,
>
>> Flipping the PPS has the effect of moving the pulse by the length of
>> the pulse so one gate in this case will move the pulse by 100MS.
>
> That is a capital M.  We are talking Mega seconds here.
> So one hundred million seconds actually.
> Did I get that right?
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray
> Sent: Monday, 9 September 2013 7:13 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] NTP/1-PPS/RS232 question
>
>
> lists at rtty.us said:
>> Actually if it's 100 ms late, you need 900 ms of inverter gates. At
>> 4.5 ns per gate that would be 100,000 gates.
>
> If I did my math right, you are off by a factor of 2000.  900 ms is 900,000 uSec.  If the delay per gate was 4.5 uSec that would take 200,000 gates.  But the delay was nSec rather than uSec, so add 3 more zeros.
>
> My HC04 data sheet says 9 ns typical at 4.5 V, so I'll give you back the factor or 2.  That leaves 100,000,000 gates.  When I run out of things to do, I'll try to convert that to cubic meters, or houses/offices.
>
>
>> Much easier to simply mod the code in the driver.
> Especially since the mod has already been done, at least for ntpd.  All you have to do is add a line to the config file.
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
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-- 

Chris Albertson
Redondo Beach, California



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