files:
combined-fec64-20110301-ip.pdf       with input protection and cable
combined-fec64-20110301-noip.pdf     with no input protection and cable


combined-fec64-20110303-ipnocable.pdf    with input protection without cable
combined-fec64-20110303-noip-nocable.pdf with no input protection without cable
combined-fec64-20110303-onlydiodes.pdf   with only diode part of input protection  without cable

combined-fec64-20110301-ip-noip-cable.pdf
difference: input protection - no input protection, with kapton cable connected

combined-fec64-20110303-ip-noip-nocable.pdf
difference: input protection - no input protection, without cable connected


left scale (red): pedestal difference
right (blue): rms difference


rms differences < 0 are suspected to be channels with a broken connection.

Channels with pedestal difference of > 20 are considered to have a bad
connection somewhere and are removed in difference plots


Conclusion: settings with high gain and/or fast shaping have a difference in rms
of > 0.5 ADC units. The highest gain has also a difference i pedestals of the
same order.

The system was kept on for 15 minuters before the test to allow the
temperature to stabilise.

Data files was taken with and without input protection with our standard
way of pulsing. Not yet analysed.


file: inprot-1.jpg
picture of input protection cards.

One card with a capacitor for make it AC coupled,
and one with the resistor and diodes.

file: inprot.gif
schematics of protection circuit