[time-nuts] Need a schematic of Trimble 2003 era Thunderbolt RX
GandalfG8 at aol.com
GandalfG8 at aol.com
Wed Oct 23 04:42:11 EDT 2013
Hi Bob
As far as I'm aware there is no schematic available for the Thunderbolt,
I'm pretty sure it would have been shouted here with glee is anyone had found
one:-)
If your specific requirement though is to monitor for failure of the 10MHz
output then monitoring the DC conditions before any output capacitor
doesn't strike me as being adequate.
Whilst it's quite possible that a DC failure in the output circuit, or
perhaps a significant change in DC operating conditions, could indicate a loss
of the 10MHz signal, the reverse would not seem to be necessarilly
implied, oscillator failure, for example, or other component failure earlier in
the signal path, might leave any output section fully functional with DC
conditions unchanged but still with no output.
Are you sure there's no 1 PPS signal available?
Observing short pulses at relatively long PRFs is notoriously difficult and
has been commented on here on many occasions. A modern digital scope
generally has no problem but triggering an analogue scope requires a bit more
practice. Again though, even if you confirm that the 1 PPS signal is
available and healthy that in itself doesn't guarantee that the 10MHz output is the
same.
It really comes down to just how important this is to you, if you really
want to be sure whether or not there's a 10MHz output then that's what you
need to monitor.
It shouldn't be at all difficult, just a highish impedance pick off from
the circuit board should do it, or a coax coupler on the output to pick off
a small sample of the signal, plus a detector of some kind, perhaps even a
10MHz filter if you wanted a degree of confirmation that the frequency
hasn't jumped significantly, you could probably do it all with off the shelf
parts from Minicircuits without even opening the box, perhaps even on the
cheap via Ebay:-)
Regards
Nigel
GM8PZR
In a message dated 23/10/2013 07:12:50 GMT Daylight Time,
Bob.Burchett at EEonTheWeb.com writes:
Anyone have a link or PDF of the T-Bolt schematic? We are "never satisfied"
with how things that seem to be working fine might fail one day in our
critical environment SO:
The object of the game is so if the T-Bolt fails to provide the 10 MHz
signal that the loss of it will trigger a fail-over mechanism to a backup
source so we built up a monitor-keys-a-controller circuit that watches the
10 MHz and while we DO have the Trimble PDF manual it doesn't have a
schematic AND:
Issue 1 is: We are monitoring the 10 MHz output of the T-Bolt and it
appears
to be AC coupled so this isn't as easily detected and we want to tap-in
before the coupling capacitor to get a straight DC coupled signal for our
special signal monitor circuit; that is one reason for schematic need
PLUS:
Issue 2 is: We see NO signal coming from the 1 PPS BNC jack and we hear
that
this is a port that can be enabled/ disabled and we are hoping one of you
know how to enable it to output the 1 PPS which we might use to drive the
monitor circuit OR:
Optionally: how we might rewire it so we can get 10 MHz out of that
"unused"
jack to feed our monitor circuit.
Thanks!
Robert L. "Bob" Burchett WB6SLC
Certified Communications Engineer
Enterprise Electronics
22826 Mariposa Ave.
Torrance CA 90502
Direct line: 310.534.4456
FAX: 310.534.1233
Website: www.EEonTheWeb.com
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