[hpsdr] GPS 1PPS board

[Graham / KE9H]

Henry:

The Motorola UT+ (8 satellite tracking) was replaced by the
M12+ (12 satellite plus improved jitter) and is now replaced
by the iLotus M12M.(3 volt power, and more improved jitter.)
The Motorola design was sold to iLotus in Singapore.  So new
12 channel GPS timing receivers with high accuracy timing
outputs are available, quoting 10 ns (1 sigma) jitter without
granularity (sawtooth) correction and 2 ns. jitter with the correction.

http://www.ilotus.com.sg

sold in US by

http://www.synergy-gps.com/

Trimble also makes a line of timing receivers called Trimble-Resolution
that have been out there for 5 years or so.

http://www.leapsecond.com/pages/res-t/

http://www.trimble.com/timing/resolution-t.aspx?dtID=overview

Development kits for the receivers in current production are available.

--- Graham / KE9H

==


Henry Vredegoor wrote:
> Hi John, All,
>
> Thank you John for your quick answer!
>
> So this unit is not particularly suited for high precision frequency
> control, even when used with the 10KHz output signal.
>
> Thinking of getting into precise frequency control for HPSDR, are there
> other surplus GPS's currently available, better suited for frequency control
> in the opinion of this forum, besides the Motorola Oncore UT+ mentioned by
> Graham?
>
> 73,
>
> Henry.
>
>
>
>
>   
>> -----Original Message-----
>> From: John Ackermann N8UR [mailto:jra at febo.com] 
>> Sent: maandag 6 april 2009 20:50
>> To: Henry Vredegoor
>> Cc: 'Graham / KE9H'; 'Chris Salinas'; 'HPSDR discussion list'
>> Subject: Re: [hpsdr] GPS 1PPS board
>>
>>
>> It's a bit of a mix.  The 10 kHz signal is derived from the 
>> GPS' onboard 
>> oscillator which free-runs.  Once per second, the 10 kHz is "jerked 
>> back" to alignment with the PPS signal (the receiver computes 
>> only one 
>> timing solution per second).  So, over time it gives the same 
>> performance as the PPS.
>>
>> John
>> ----
>>
>> Henry Vredegoor wrote:
>>     
>>> ***** High Performance Software Defined Radio Discussion List *****
>>>
>>>
>>> Hi Graham, All,
>>>
>>> Is the jitter spec specifically for the 1pps signal only or 
>>>       
>> does this also
>>     
>>> apply to the 10KHz output?
>>> (I could imagine these being "coupled", the 1pps signal 
>>>       
>> being derived from
>>     
>>> the 10 KHz, so it would apply for both)
>>>
>>>
>>> 73,
>>>
>>> Henry.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>       
>>>> -----Original Message-----
>>>> From: hpsdr-bounces at lists.hpsdr.org 
>>>> [mailto:hpsdr-bounces at lists.hpsdr.org] On Behalf Of Graham / KE9H
>>>> Sent: maandag 6 april 2009 18:12
>>>> To: Chris Salinas
>>>> Cc: HPSDR discussion list
>>>> Subject: Re: [hpsdr] GPS 1PPS board
>>>>
>>>>
>>>> ***** High Performance Software Defined Radio Discussion List *****
>>>>
>>>> Chris:
>>>>
>>>> Although a cheap way to get started, this is a navigation 
>>>> receiver, not 
>>>> a timing receiver,
>>>> and it will not be a good choice for frequency control.  This 
>>>> one's spec 
>>>> is that the 1 pps
>>>> signal has a jitter spec of +/- 1 microsecond.  Timing 
>>>> receivers, such 
>>>> as the Motorola
>>>> Oncore UT+ have a timing mode, that provides jitter around +/- 50 
>>>> nanoseconds,
>>>> without sawtooth correction, and sub 10 nanoseconds with sawtooth 
>>>> correction.
>>>>
>>>> You want a timing receiver, or a receiver with a timing mode 
>>>> option for 
>>>> frequency
>>>> control.
>>>>
>>>> --- Graham / KE9H
>>>>
>>>> ==
>>>>         

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