[GPS_Standard] Re: GPS_Standard Digest, Vol 6, Issue 2

Thu Apr 19 10:04:19 EDT 2007

Andreas,
I tested tu use the 10 kHz dived down to 1 Hz and compared with the 1 pps 
output in ZAZ's rx. No difference in my case. In fact the intrinsic 
possibilities of the GPS signal are determined by the 1pps signal and you 
cannot invent "in between" sync impulses.
73
Arie

----- Original Message ----- 
From: <gps_standard-request at mailman.qth.net>
To: <gps_standard at mailman.qth.net>
Sent: Tuesday 17 April 2007 10:00
Subject: GPS_Standard Digest, Vol 6, Issue 2

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> Today's Topics:
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>   1. PIC Software (Andreas Stefan)
>   2. PIC Software (Andreas Stefan)
>   3. Re: PIC Software (Bert, VE2ZAZ)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 16 Apr 2007 11:38:15 +0200
> From: Andreas Stefan <andreas.stefan at web.de>
> Subject: [GPS_Standard] PIC Software
> To: gps_standard at mailman.qth.net
> Message-ID: <1186915179 at web.de>
> Content-Type: text/plain; charset=iso-8859-15
>
> Hello List, hello Bertrand,
> my name is Andreas, DL5MGD.
> First let me say thanks for a very fine piece of hard- and software dear 
> Bertrand.
> I have one question. My gps receiver delivers not only the 1pps sig, but 
> also a 10kHz sig which is locked to the 1pps sig. Is it possible to 
> convert the software for the pic so that the user can decide if he wants 
> to use the 1pps or the 10kHz sig as reference for the fll? So the locking 
> time can be increased (i think, hi)
> 73
> Andreas, DL5MGD
> _______________________________________________________________
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> ------------------------------
>
> Message: 2
> Date: Mon, 16 Apr 2007 11:42:04 +0200
> From: Andreas Stefan <andreas.stefan at web.de>
> Subject: [GPS_Standard] PIC Software
> To: gps_standard at mailman.qth.net
> Message-ID: <1186919193 at web.de>
> Content-Type: text/plain; charset=iso-8859-15
>
> Hello List, hello Bert,
> my name is Andreas, DL5MGD.
> First let me say thanks for a very fine piece of hard- and software dear 
> Bertrand.
> I have one question. My gps receiver delivers not only the 1pps sig, but 
> also a 10kHz sig which is locked to the 1pps sig. Is it possible to 
> convert the software for the pic so that the user can decide if he wants 
> to use the 1pps or the 10kHz sig as reference for the fll? So the locking 
> time can be increased (i think, hi)
> 73
> Andreas, DL5MGD
> _______________________________________________________________
> SMS schreiben mit WEB.DE FreeMail - einfach, schnell und
> kostenguenstig. Jetzt gleich testen! http://f.web.de/?mc=021192
>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 16 Apr 2007 08:33:51 -0400
> From: "Bert, VE2ZAZ" <ve2zaz at sympatico.ca>
> Subject: Re: [GPS_Standard] PIC Software
> To: "Andreas Stefan" <andreas.stefan at web.de>,
> <gps_standard at mailman.qth.net>
> Message-ID: <27059BAB592E43E2A86A7C2E438C9325 at zaub2>
> Content-Type: text/plain; charset="ISO-8859-15"
>
> Hello Andreas,
>
>
> The way the firmware is built relies on 1-second (actually, 16-second)
> windows to compute the frequency offset. This provides the ability to use
> 8-bit and 16-bit registers to count for almost everything, which is easily
> manageable with an 8-bit PIC. Using a 10KHz as the window gate would force
> the firmware to count much larger numbers. It would require a complete
> re-design of the front end firmware and would not really decrease the
> initial acquisition time, and would offer no improvement on accuracy.
>
> A 100us (1/10KHz) sampling window for a 10MHz signal would give a 
> resolution
> of one Hz in 1000 10MHz cycles. This resolution would provide the ability 
> to
> detect only 10KHz off frequency on the 10MHz signal. Your oscillator
> normally has a 1Hz end-to-end tuning range! So we would have to take 
> orders
> of magniture more of these samples to get a decent resolution....which
> brings us back to the current 16-second window! It provides a one Hz in
> 160,000,000 cycles resolution, or 1/16 of Hz of the 10MHz... 
> Unfortunately,
> we are dealing with high accuracy here! No way out... And besides, the 
> vast
> majority of GPS receivers on the market provide only a 1 PPS output.
>
> I hope that I have answered your question. If not, let me know.
>
> Regards,
>
> Bert, VE2ZAZ
>
> ----- Original Message -----
> From: "Andreas Stefan" <andreas.stefan at web.de>
> To: <gps_standard at mailman.qth.net>
> Sent: Monday, April 16, 2007 5:42 AM
> Subject: [GPS_Standard] PIC Software
>
>
> Hello List, hello Bert,
> my name is Andreas, DL5MGD.
> First let me say thanks for a very fine piece of hard- and software dear
> Bertrand.
> I have one question. My gps receiver delivers not only the 1pps sig, but
> also a 10kHz sig which is locked to the 1pps sig. Is it possible to 
> convert
> the software for the pic so that the user can decide if he wants to use 
> the
> 1pps or the 10kHz sig as reference for the fll? So the locking time can be
> increased (i think, hi)
> 73
> Andreas, DL5MGD
> _______________________________________________________________
> SMS schreiben mit WEB.DE FreeMail - einfach, schnell und
> kostenguenstig. Jetzt gleich testen! http://f.web.de/?mc=021192
>
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> End of GPS_Standard Digest, Vol 6, Issue 2
> ******************************************
> 