On 3/6/07, Gregory W Heckler <[EMAIL PROTECTED]> wrote:
I've noticed that the DLL of my software receiver settles to +15 Hz, and the true IF is +24 kHz from the predicted IF. This would indicate that the 64 MHz board clock is ~1 kHz from its spec value. This, in itself is not a problem, but I was wondering if this was within tolerances of the onboard XO?
I believe the XO on the USRP has a 50ppm spec, so 1kHz is well within that.
The real problem lies in the fact that the carrier tracking loop (a 3rd order PLL) of my software receiver cannot achieve phase lock. The phase jitter looks high, and the LO frequency drifts so much it dominates over the Doppler derived from satellite motion. If anyone would like any GPS IF data I would be happy to email it to your personal email address (indicate how many seconds of data you would like). Thanks!
On a side note, have you seen that SiGe device available from Spark Fun Electronics? I posted earlier today about it. It might be of interest? http://www.sparkfun.com/commerce/product_info.php?products_id=8238# Brian _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
