10MHz and 1pps signal synchronous

Hi All,

On the FAQ page http://gnuradio.org/redmine/wiki/gnuradio/USRP2GenFAQ it
is said “the PPS signal should be synchronous to the 10 MHz reference”.
I this really necessary ?

Can I run with a pps signal but without 10MHz ?

BR/
Per

On 01/18/2010 01:53 PM, Per Z. wrote:

Hi All,

On the FAQ page http://gnuradio.org/redmine/wiki/gnuradio/USRP2GenFAQ it
is said “the PPS signal should be synchronous to the 10 MHz reference”.
I this really necessary ?

If you need to be able to sync the sampling to the exact 10ns sample,
then you need it synchronous. You don’t need to be synchronous if:

  • you are ok with +/-10ns ambiguity,
  • it is ok that some seconds will contain exactly 100e6 samples while
    some will have 100e6 - 1 or 100e6 + 1 samples,

Can I run with a pps signal but without 10MHz ?

Yes, you can, with the same caveats as above.

Matt