[time-nuts] TPLL2 and Tbolt Tic

WarrenS warrensjmail-one at yahoo.com
Fri Dec 16 17:44:31 UTC 2011


Sounds like an interest project, Do you have any performance plots?

It would be interesting to see how it compares with the TPLL2 which uses a 
$5.00 USB sound card to greatly improve the performance of the old all 
analog $10 TPLL.
Using mostly junk box parts, and a 3e-13 selected HP10811 reference Osc, the 
TPLL2 can do fast, high resolution Frequency and ADEV plots that closely 
match the best testers and can provide taus plots starting as fast as 0.1ms 
with a noise floor as low as 1e-14/sec. (limited by the reference Osc).

Using John's TimeLab software, live, real time ADEV plots showing tau data 
from 1ms to 1 sec can be plotted for an Osc in as little as 10 seconds with 
one key press (and a couple of Enters).
This can be useful for quick Osc testing because using a fast, low noise 
tester, the tau of many high end oscillators is pretty flat between 0.1 sec 
and 1 sec taus.
Also possible is 1e-12 freq measurements in about 100 ms, with data logging 
fast enough at up to 10k/sps, and resolution high enough at 10fs, to measure 
the effects of line noise and it's harmonics on the oscillator's frequency.

The TPLL2.0 provides good short term sub picoseconds resolution. For longer 
runs the TPLL2 can be combined with a single or dual TBolt Tic to provide 
long term resolution as low as 0.1 ns(1e-10/sec), which is good enough to 
measure and compare Cs from day to day.

ws

*************
Ulrich, DF6JB   posted:

I have just finished the work on a pcb
... snip ...
The board features an AD654 voltage to frequency converter which
is connected to the PLL's loop voltage and delivers pulses to an
ATMEGA32 counter input. That would make it possible to
use the board as an correct implementation of the tight pll
method as discussed here 




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