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Diffstat (limited to 'host/docs/sync.dox')
| -rw-r--r-- | host/docs/sync.dox | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/host/docs/sync.dox b/host/docs/sync.dox index 5a0870bea..8c609f407 100644 --- a/host/docs/sync.dox +++ b/host/docs/sync.dox @@ -64,10 +64,10 @@ synchronize multiple pairs of devices. \section sync_time Synchronizing the Device Time The purpose of the PPS signal is to synchronously latch a time into the -device. You can use the `set_time_next_pps(...)` function to either +device. You can use the uhd::multi_usrp::set_time_next_pps() function to either initialize the sample time to 0 or an absolute time, such as GPS time or UTC time. For the purposes of synchronizing devices, it doesn't matter -what time you initialize to when using `set_time_next_pps(...)`. +what time you initialize to when using uhd::multi_usrp::set_time_next_pps(). \subsection sync_time_reg Method 1 - poll the USRP time registers @@ -100,15 +100,13 @@ PPS edge, and the user can also parse this string to determine GPS time: usrp->set_time_next_pps(uhd::time_spec_t(gps_time+1)); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -\subsection sync_time_internalgps Method 3 - internal GPSDO +\subsection sync_time_mimocable Method 3 - MIMO cable -USRP devices with internal GPSDOs properly configured will automatically -configure themselves to set the VITA time to current UTC time. See \ref page_gpsdo -for more details. +Note: This only applies to USRP2 and N200/N210. This method does *not* +require a separate PPS input to the devices, but it is limited to +a total of 2 USRPs. -\subsection sync_time_mimocable Method 4 - MIMO cable - -A USRP device can synchronize its time to another USRP device via the +A USRP2 device can synchronize its time to another USRP device via the MIMO cable. Unlike the other methods, this does not use a real "pulse per second". Rather, the USRP device sends an encoded time message over the MIMO cable. The slave device will automatically synchronize to the |