• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 30 subscribers
  • Views 397 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TDC7200: Delay lines and other strategies for avoiding deadtime.

TDC7200: Optical Encoder Setup Questions

Johann Van Niekerk
Prodigy 40 points
Part Number: TDC7200

Tool/software:

I have a custom encoder project where I want to measure the time between three gates monitored by IR TX and RX points, Couple of questions around the circuit above 

1) My average pulse durations between start signal and last stop signal will be 200uS and as fast as 1uS the comparators is in the nS range, is my understanding correct here that will be fine for the desired resolution ?

2) I saw an application note that you can monitor and detect more then 1 stop signal so will the above implementation work to provide me two duration between start and two stops ?

3) Looking at the resolution and delays. is a <1uS average error doable  ?

  • +1
    TI__Mastermind 43730 points

    1) My average pulse durations between start signal and last stop signal will be 200uS and as fast as 1uS the comparators is in the nS range, is my understanding correct here that will be fine for the desired resolution ?

    2) I saw an application note that you can monitor and detect more then 1 stop signal so will the above implementation work to provide me two duration between start and two stops ?

    3) Looking at the resolution and delays. is a <1uS average error doable  ?

    1. Yes, there are two modes of operation depending on the measurement range.  For your application, you will be using mode 2.   

    2. Yes, the device allows for more than 1 stop signal.  Please note the specification highlighted below regarding the min time between two stop signals. 

    3. Yes, that is doable.  Note that typical accuracy in mode 2 is around 28ps.   

  • 0 in reply to Eddie LaCost
    Prodigy 40 points

    Thank you, I see in both instances, the clock input is scalable between 8 to 16mhz max. since the accuracy reference in mode 2 is tested at 8mhz, does running at 16mhz reduce that accuracy to 14ps or is the two not linearly related ?