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TDC7200EVM: Comparing two signals

Part Number: TDC7200EVM
Other Parts Discussed in Thread: TDC7200, TDC7201

Hi Team, seeking some inputs.

1 PPS from a GPS and 1 PPS from a 10 MHz stable OCXO. Would the TDC7200 be a good choice for this? Essentially want to calculate the phase shift between the rising edges of these two signals and save them. 

trying to do Very long baseline interferometry on a balloon-borne radio telescope. This requires to do very precise positional tracking. Flying a high precision oven controlled 10 MHz crystall oscillator as reference signal and also to time stamp our data. An important task in this respect is to be able to measure the phase drift between our stable 10 MHz OCXO and 10 MHz from the GPS module that we are flying. In order to achieve, thought of using the TDC module. 

Thank you in advance.

-Mark

  • Hello Mark,

    Thanks for posting to the sensing forum! The TDC can be used to time the difference between the two pulses in the way that you mentioned above by timing the difference between two rising edges. Just keep in mind that we do not recommend having free running inputs on the START/STOP inputs. Another thing to note is that there is also a minimum required time between START and STOP signals of 12ns in Mode 1 and for Mode 2 it is dependent on the reference clock for the device, if the customer is expecting measurements below this they might need to consider a two input setup using TDC7201.

    Let me know if there are any other questions!

    Best,

    Isaac