[time-nuts] Performance of TDC7200

[Li Ang]

I've done some tests with TDC7200 and TDC_GP22 few months ago.(https://www.febo.com/pipermail/time-nuts/2016-May/098170.html)


Here is the performance test of my recent board.



http://www.qsl.net/b/bi7lnq/Projects/freqcnt6.0/schematic.pdf
http://www.qsl.net/b/bi7lnq/Projects/freqcnt6.0/freqcntv6.0.jpg


The "analog front end" is 74lvc1g04/nc7sz125. 3 TDC7200s are on the board. Only TI mode is tested at the moment.(the truth is I forgot to connect the SPI port to FPGA ......, I need to reuse the config ports to implement a bidirectional SPI to read the counters in FPGA)
DUT and REF are from a homebrew distribution amp( http://www.qsl.net/b/bi7lnq/distribution_amp/v1.5/10M_distributor.pdf), the source is a FE180 OCXO.


1) the noise of 74LVC and NC7 are different.
2) the performance of my counter in TI mode is almost the same as the Agilent 53220A
http://www.qsl.net/b/bi7lnq/Projects/freqcnt6.0/data/20161209/nc7sz125_74lvc1g04_53220a.png


I also tried to measure 3 OCXOs at the same time. FE180, OCXO8663, free running TBOLT
http://www.qsl.net/b/bi7lnq/Projects/freqcnt6.0/data/20161209/freqcnt_v6_20161209.png
http://www.qsl.net/b/bi7lnq/Projects/freqcnt6.0/data/20161209/freqcnt_v6_20161209_3corneredhat.png


TODO list:
1) web based interface, calculate and show *DEVs with javascript on Chrome browser
2) front end experiments




Regards


Li Ang / BI7LNQ