• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 527 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:

TDC1000-TDC7200EVM: Control two Transducers in ultrasonic level measurement

TDC1000-TDC7200EVM: Control two Transducers in ultrasonic level measurement

Nabila cherifi
Prodigy 40 points

Part Number: TDC1000-TDC7200EVM

Hi scot,

thanks a lot for your answers, i followed all what you've said and all works as i want :)

but now i have some questions : 

-What is the impact of the number of pulses in the two configurations : Transducer A and transducer B with a distance of 39mm, Transducer A with a reflector ? the frequencies are in range of 1MHz up to 4MHz.

-How to choose the right value of threshold voltage? and what is it's influence ?

-If i want to increase the amplitude of my received echos, is it better to excite more the transducer? if yes, how to do that externally knowing that with this *tdc1000 EVM" the maximum voltage is up 3,5V i guess?

                                                                                          , or by amplifying the received signal? if yes how can i do that?

-I've seen that by using one transducer we have to pay attention on which distance we use cause we've the ringing. It can influences the returned echo, which means have a false value. So how to reduce that without changing the distance we use?

-i didn't found more information on the Auto Zero Period, So what is really its role and impact on the measurement of time of flight?

If my questions are not too clear just let me know :) 

Really a great thanks

Nabila

  • 0
    TI__Genius 11015 points
    Hi Nabila,

    I have received your question, I will follow-up within a couple of days on this.

    thanks

    Bharat
  • 0 in reply to Bharat Aravamudhan
    TI__Genius 11015 points
    Hello Nabila,

    Increasing pulses increases the Sound Pressure Level (SPL). However after certain number of pulses the Transducers saturate (Refer the Transducer Spec). You can measure the signal at the receive line with a microphone to check the SPL.
    First test a small pulse and measure the amplitude at the receive line, keep increasing the pulses until you have reached a maximum amplitude (SPL).

    Refer to section 8.3.6.3 in the Datasheet: It shows how the comparator works with respect to the Threshold value. The threshold value should typically be above the noise level & below the signal on the COMP pin.

    Increasing the excitation voltage can help the transducer.

    You can amplify the receiving signal using the internal PGA. Also use the amplifier U2 in the TX as in the TDC1000GAS EVM.
    www.ti.com/.../sniu026a.pdf

    Let us know the distance that you are trying to measure, you can also refer to the Short distance TOF Section (8.4.6.1 Short TOF Measurement) in the TDC1000 Datasheet : www.ti.com/.../tdc1000-q1.pdf