Updated documentation and improved XCVR RSSI calculation

    Documented dboard sensors
    Documented DBSRX2
    Added description of direct conversion vs low IF for each dboard
    Added E1xx docs for adding refclock and pps connectors

    XCVR rssi calculation was in unscaled dB units
        Used chart in datasheet (pg 16) to rescale to dBm

1 files changed, 38 insertions, 0 deletions

diff --git a/host/docs/usrp_e1xx.rst b/host/docs/usrp_e1xx.rst
index fb5848bad..2818a0a65 100644
--- a/host/docs/usrp_e1xx.rst
+++ b/host/docs/usrp_e1xx.rst
@@ -63,3 +63,41 @@ Run the following commands to restore the clock generator to a usable state:
 
     cd <install-path>/share/uhd/usrp_e_utilities
     ./usrp-e-utility --fpga=../images/usrp_e100_pt_fpga.bin --reclk
+
+
+------------------------------------------------------------------------
+Clock Synchronization
+------------------------------------------------------------------------
+
+
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Ref Clock - 10MHz
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+The E1xx has a 10MHz TCXO which can be used to discipline the flexible clocking by 
+selecting REF_INT for the clock_config_t.
+
+Alternately, an external 10MHz reference clock can be supplied by soldering a connector.
+
+* Connector J10 (REF_IN) needs MCX connector WM5541-ND or similar
+* Square wave will offer the best phase noise performance, but sinusoid is acceptable
+* Power level: 0 to 15dBm
+* Select REF_SMA in clock_config_t
+
+
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+PPS - Pulse Per Second
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+An exteral PPS signal for timestamp synchronization can be supplied by soldering a connector.
+
+* Connector J13 (PPS) needs MCX connector WM5541-ND or similar
+* Requires a square wave signal
+* Amplitude: 3.3 to 5Vpp
+
+Test the PPS input with the following app:
+
+* <args> are device address arguments (optional if only one USRP is on your machine)
+
+::
+
+    cd <install-path>/share/uhd/examples
+    ./test_pps_input --args=<args>