[time-nuts] TADD-2 modification

[Magnus Danielson]

Fellow time-nuts,

I've modified my TADD-2:s by sniffing the input clock on pin 2 of the 
PIC and wired it over to the output 6 signal selection pin header where 
it goes further to the output polarity inverters and finally output.

This way I can use the input shaper of the TADD-2 and output driver to 
improve my sine signals slew-rate.

The TADD-2 only generates 5 frequencies (it has two variants of 1 Hz, 1 
Hz and PPS) so I thought I could use one of the outputs for this purpose.

First test-runs shows that I have now lowered my measurement floor at 1 
s from 2,83E-11 to 1.05E-11. This could be improved on by removing some 
unnecessary damping needed until I have DC-blockers in place.

I think the modification is encouraging as it stems from only adding a 
wire and un-jumping a jumper.

Cheers,
Magnus