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TDC1000/7200 for 4-sensor TDOA calculation

Chris Baron
Prodigy 95 points
Other Parts Discussed in Thread: TDC1000, TDC7200

I realize this isn't the classic application for these chips but please if you could think outside the box a little I think they might have application to my needs.

I want to detect the location of an impact on a steel mounting plate via TDOA with 4 piezo sensors.  So I don't think there needs to be any "transmission" from the AFE because the impact will provide the signal.


What I'm thinking is continuously (or every x mS)  triggering the start signal and then when an impact occurs measure the "time of flight" to each of the sensors.  By using 4 sensors we can use the first reception as zero time and difference the arrival of the signal to each of the others.  The time from the start signal doesn't matter only between the times of arrival at each sensor.


Does this make sense?  Seems like there is a lot of precision timing and analog stuff in these chips that can be used.  I realize I might have to use two chips to interface to the 4 sensors.


Thoughts appreciated.

  • 0
    TI__Expert 4725 points

    Chris,

    Interesting application but I believe the TDC1000/TDC7200 won't work for you. Here's a few thoughts why:

    1. The TDC1000 facilates TOF (Time Of Flight) measruements by creating a START signal at transducer excitaiton and a STOP when the echo is received. These two signals are input to the TDC7200.
    2. The TDC1000 can service (be connected to) 2 piezo transducers but can only receive input from one per measurement. So to perform the measurement you're trying would require 1 TDC1000 and TDC7200 per transducer.
    3. In your application where you "trigger" the TDC1000 every 1 ms your START pulse can't be used and you really need to measure the delta T between 2  different TDC1000 device STOP pulses. However, the TDC7200 is designed with positive TOF in mind. For your application I don't believe that's the case.