[Hackrf-dev] short-term frequency stability requirements for the clockIN

[Kristoff]

Hi all,


I intend to use my hackRF for QO100 transmissions.
For frequency-stability, I want to use a GPSDO as 10 MHz clock.

I bought a 10 MHz GPSDO from dxpatrol, but that one seems to create a 
sine-wave instead of a square-wave so I cannot use that one for the hackRF.


I also have two ublox neo8 receiver-modules that do are able to generate 
a 10 MHz square-wave, .. but the signal seams to be very strange: 2 
longer pulses followed by 3 shorter pulses. Also the time between the 
pulses seems to very, so the jitter is very very bad.

The long-term stability of the signal does is very good (say every 10 
ticks), and the frequency is very correct (about 0,2 Hz error compared 
to the frequency reference signal of RWM at 9.996 MHz when I measured 
it), but at a the very-short term, it has a lot of jitter.


Question.
What are the requirements for the 10 MHz clock-in signal for the hackRF.
Is a signal like this good enough for the hackRF. Does the clock require 
a very precise pulse-per-pulse stability, or does it 'level out' jitter 
of the clock?



If this is not good enough, my next option is to convert the sine-wave 
of the GPSDO of dxpatrol into a block-wave and try to use that for the 
hackRF.


Thx in advance.


Kristoff (on1arf)