[time-nuts] FS: Brandywine GPS-4 - Qty: 7 available - AdditionalSpecs

Didier Juges didier at cox.net
Sat Jun 28 22:45:00 UTC 2008


The GPS-4 manual is on my web site. Search for GPS-4

http://www.ko4bb.com/cgi-bin/manuals.pl

Didier KO4BB 

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Scott A Sybert
> Sent: Saturday, June 28, 2008 3:24 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] FS: Brandywine GPS-4 - Qty: 7 available 
> - AdditionalSpecs
> 
> Hi Guys...
>  
> A number of you have been inquiring about additional 
> specifications on these units.    Here's what I've found.  It 
> looks like it may address some of your questions.  I think 
> this is all I'm going to be able to turn up on these units.  
> Most of the data we had on them is long gone.
>  
> Scott
>  
> -------------------------------
>  
> 
> 1.  Section 2.2.1: could you spec the min/max VOH/VOL and IOH/IOL
> > >       of the PPS output.
> 
> Voh min 2.4V
> 
> Vol max 0.4V
> 
> 
> > >
> > >   2.  Section 2.2.2: the amplitude of the 10MHz is at least 1Vrms
> > >       in 50ohm: please also spec a maximum.
> 
>         
> 
> 1.5V RMS Max
> 
> 
> > >
> > >   3.  Section 2.2.3: could you spec the min/max VOH/VOL 
> and IOH/IOL
> > >       of the 19.6608MHz output.
> 
> 50pf load
> 
>    Voh 4.5V min
> 
>    Vol max 0.4V
> 
>    Iol/Ioh ±25mA
> 
>  Load 50 ohms
> 
>    Voh 2.4V min
> 
>    Vol 0.4V max
> > >
> > >   4.  Section 2.2.3: could you spec the jitter and the wander of
> > >       the 19.6608MHz output.  (I am concerned about the frequency
> > >       variation over a 1-second duration.)
> 
> Short term stability
> 
> Square root of Allan Varience: 1x10-10, tau = 1 second
> 
> Phase jitter:  100ps
> 
> 
> > >
> > >   5.  Section 2.3.1: could you spec the min/max VIH/VIL 
> and IIH/IIL
> > >       of the Reset input.
> 
> Voh min 4.5V
> 
> Vol max 0.4V
> 
> Iol<0.1ma
> 
> Ioh 1mA max
> 
> 
> > >
> > >   6.  Section 2.7: I do not understand the open-collector pulled
> > >       to ground, then the next line mentions a max 
> pull-up voltage.
> > >       Please clarify.
> 
> This is an output which is open collector, pull up through a 
> 1K resistor to 5 volts.  "open collector pulled to ground" 
> was an incorrecte statment.
> > >
> > >   7.  Section 2.7: there seems to be an inconsistency about the
> > >       active level of the "Fault" pin: it is active low here, but
> > >       active high in the table of section 2.9.
> > >
> > >   8.  Section 2.7: please define the criteria for the Fault output
> > >       to be active.
> > >
> > >   9   Section 3.4: also a discrepancy between the text and the
> > >       table about the active level of the Fault output.
> > >
> 
> >   6.  Section 2.7: I do not understand the open-collector pulled
> > >       to ground, then the next line mentions a max 
> pull-up voltage.
> > >       Please clarify. 
> 
> This is an output which is open collector, pull up through a 
> 1K resistor to 5 volts.  "open collector pulled to ground" 
> was an incorrect statement.
> > >
> > 
> 
> User connection is to COLLECTOR of transistor (via 100R 
> internal protection).  The user can connect this collector 
> through a resistive load to a positive voltage which has the 
> maximum specified (with reference to pin 5 GND at connector).
> 
>  
> 
> When the GPS4 output is asserted (ie NO FAULT or TIME LOCKED) 
> the transistor is turned ON sinking current from the user's 
> positive supply through the users load and the 100R resistor 
> inside the GPS4
> 
> 
> > >   7.  Section 2.7: there seems to be an inconsistency about the
> > >       active level of the "Fault" pin: it is active low here, but
> > >       active high in the table of section 2.9.
> > >
> 
> Pin 9 of the 9way Dtype socket is pulled LOW by the open 
> collector transistor for NO FAULT.
> 
> The transistor is OFF in the case of a fault (which includes 
> lack of power)
> 
> 
> > >   8.  Section 2.7: please define the criteria for the Fault output
> > >       to be active.
> > >
> 
>  
> 
> There are 4 fault sources:-
> 
>  
> 
> Processor cannot run (watchdog asserts fault output)
> 
>  
> 
> 8 hours of no reception of satellites (eg faulty antenna)
> 
>  
> 
> Frequency Error (GPS4 cannot control internal frequency 
> standard (OCXO) to track reference 1pps from GPS)
> 
>  
> 
> DAC is near the end of its adjustment range (MAX 61440 MIN 4096)
> 
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