[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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