[time-nuts] 10MHz Rubidium reference source for frequency counter

Karen Tadevosyan ra3apw at mail.ru
Mon Nov 3 08:48:01 EST 2014


Hi,

yes, it is my fault - my set up (connections)  for TI mode was not correct. 

According your advices I went back to the frequency mode and set gate / sample time to 1 second for CNT-91 and TimeLab.
Then I switched on "Smart Frequency" and "Interpolator Calibration" option on CNT-91

	1. Setting -> Misc -> Smart Meas -> Smart Frequency -> ON 
	Smart Frequency (valid only if the selected measurement function is Frequency or Period Average). 
	By means of continuous timestamping and regression analysis, the resolution is increased for measuring times between 0.2 s and 100 s.

	2. Setting -> Misc -> Smart Meas -> Interp Calib ON
	 Interpolatator Calibration - By switching off the interpolator calibration, you can increase the measurement speed at the expense of accuracy.

Please see the result  with and without these CNT-91's options (Smart Frequency and Interpolator Calibration)
https://dl.dropboxusercontent.com/u/21338179/hamradio/OCXO_Adev/morion%20ocxo%20adev%20freq%20mode%20smartfreq%20sample_1s%20interpcalib_on.jpg . 

This result is for the internal CNT-91 reference source. I will check with external reference second Morion OCXO shortly.  

Thanks,
Karen



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