[hpsdr] GPS 1pps output

[Dick Faust]

Glen

The "white paper" that you are looking for is on QRP Labs site. Huff 
Puff Calibration

http://qrp-labs.com/ultimate3/u3info/u3hp.html

The GPS module puts out NEMA messages and 1pps.  There is NOT /usually/ 
a 10MHz output from a GPS part.  A GPSDO is a "GPS Disciplined 
Oscillator" which requires a PLL and other hardware.

The oscillator being controlled in the QRP Labs is a Silicon Labs part 
Si5351A

Analog Devices has a nice simple app note on PLLs

http://www.analog.com/en/landing-pages/001/glp2-pll-fundamentals-mt-086.html

References 2 & 3 are very good but I would prefer

Stevens, Donald R., PHASE-LOCKED LOOPS FOR WIRELESS COMMUNICATIONS 
Digital, Analog and Optical
Implementations, Second Edition, NEW YORK, KLUWER ACADEMIC PUBLISHERS, 2002

An easier to obtain paper is: Long. Prof Steve, PLL_intro_594a_s05.pdf, 
UCSB/ECE Department, April 27, 2005

https://www.ece.ucsb.edu/~long/ece594a/PLL_intro_594a_s05.pdf

Dick K9IVB


On 6/12/2018 5:50 PM, K4KV wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hello,
>
> I have just ordered a qrp labs beacon kit with a gps unit that has a 
> 1pps output.
>
> I have been told that they use software to 'read' the gps and then 
> automatically
>
> correct the Siliconix programmable oscillator.  Granted, this takes 
> quite a while to
>
> get it right.
>
> But still, I cannot see how it can be very accurate compared to a 
> 10Mhz GPS output
>
> reference.
>
> These 1pps output modules are quite inexpensive.
>
> Can someone point me to a white paper where someone describes how to 
> use software
>
> to correct a programmable oscillator using a 1pps system?
>
> 73
>
> Glen K4KV
>
>
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