[time-nuts] New NTBW50AA

[Arthur Dent]

I have a slightly earlier version, or a close cousin, of the NTBW50AA that 
I modified and I've posted photos of it on this list before: 
http://i906.photobucket.com/albums/ac262/rjb1998/NTPB15AA05.jpg

The LH plot from the NTBW50AA by quartz55 doesn't look quite right. Here 
is a LH plot from my NTPB15AA  unit with most of the scale factors set the 
same as the scale factor in the plot from the NTBW50AA to make it easier 
to compare. 
http://i906.photobucket.com/albums/ac262/rjb1998/NTPB15A_zps19b3bd33.jpg

If you look at the temp plot from my unit it has small steps and is what I'd 
expect to see. The plot from the NTBW50AA looks like it has some smaller 
steps but it looks like it hits a limit at 36.750 and doesn't go beyond that 
value, which isn't right. It looks like a higher order bit is being turned on 
and off randomly causing the large apparent jump in temp, which 
probably isn't really happening because some of the other traces would 
be affected by any real jump that large. You could just ignore it because it 
would probably only have an effect during carryover. 

The NTBW50AA oscillator  probably hasn't settled down yet because the 
DAC voltage is changing a lot more than mine and the 10Mhz doesn't look 
anywhere near as stable. The design of the 2 units appears nearly identical 
so I'd expect similar performance. Also the OSC ADEV at 10000 tau isn't close 
to what mine appears to be. That may improve after the unit has been on
for a month or so but the temp plot just doesn't look right so the sensor may
be bad.

-Arthur