[Discuss-gnuradio] USRP1 + gps reference clock

2010-10-30 Thread Dawid SQ6EMM
Hello,

is it possible to stabilize USRP1 clock using external GPS reference
clock of 10MHz?

Regards,

Dawid.


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Re: [Discuss-gnuradio] USRP1 + gps reference clock

2010-10-30 Thread Juha Vierinen
Modify the usrp so that it is in slave clocking mode. Then feed a GPS
stabilized master clock onto the board. The on board clock is 64 MHz,
but e.g., 60 MHz is known to also work, and it is easier to generate
from 10 MHz.

http://gnuradio.org/redmine/wiki/1/USRPClockingNotes

You basically need to follow these steps:
- Solder an SMA connector into J2001. This is the clock input. Be
careful when soldering the SMA connector so you don't break the
delicate trace from J2001 to C927.
- Move R2029 to R2030. This disables the onboard clock. R2029/R2030 is
a 0-ohm resistor.
- Move C925 to C926.
- Remove C924.

The only way to get PPS is to use the gr-gpio firmware, which can be
used to insert digital signals into the least significant bits of I
and Q.

juha

On Sat, Oct 30, 2010 at 14:51, Dawid SQ6EMM sq6emm+gnura...@hamradio.pl wrote:
 Hello,

 is it possible to stabilize USRP1 clock using external GPS reference
 clock of 10MHz?

 Regards,

 Dawid.


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