pulse-distribution-amplifier.md

 # pulse-distribution-amplifier
 
-## Current version PDA 2017.07
+## Rise-time (PDA 2017.07)
 
-Rise-time measurement on 2019-12-16. BNC-cable to 4 GHz LeCroy oscilloscope, DC 50 Ohm termination, 10%-to-90% rise time measurement result is <700 ps.
+Rise-time measurement on 2019-12-16. BNC-cable to 4 GHz LeCroy oscilloscope, DC 50 Ohm termination, 10%-to-90% rise time measurement result is <700 ps. The 1PPS output uses five parallel outputs of the clock-buffer, driving about 2.7V into a 50 Ohm load and 3.3V into 1 MOhm.
 
 ![pda_rise-time_2019-12-16](uploads/aea60c5d88cfe09efa10559d16d23e45/pda_rise-time_2019-12-16.png)
 
+## Ouput skew
+
+Output-to-output time difference measured with Keysight 53230A counter. Measurements done before any tuning with the trimmer-capacitors. After tuning it is possible to achieve <10 ps output-to-output skew. The delay from the input to any output has not been measured accurately, but it should be around 15 ns (to be verified).
+
+![pda_output_skew_2021-05](uploads/8bf10af50e902a8aa98fae175f451db7/pda_output_skew_2021-05.png)
 
 ## Past versions