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Original question:

PGA460: Everything You Need to Know for Ultrasonic ToF (Air-Coupled) [Collateral, Tools, Designs]

PGA460: decreasing the blind range of detection to 0.5 cm

Zeinab Ramshani
Prodigy 100 points
Part Number: PGA460

PGA460 works for 5cm to 1m range in higher Freq, is there any way to decrease the blind range? is there any other AFE available, suitable for 0.5 cm to 50cm detection range?

  • 0
    TI__Mastermind 23045 points

    Hello Zeinab,

    The reason you are having a hard time measuring at such a close range is because of the excitation ringing decay of the transducer will not allow you to capture any return signals until the voltage comes back down. The best way to decrease the blind period is by using a bistatic configuration which means you will use one transducer to generate the ultrasonic signal and a separate transducer to receive the signal. Additionally, you want to be careful at the frequency at which you are using to transmit your signal, the higher the frequency the faster it will attenuate once it is generated.

    Feel free to watch this training video series that talks about some of these subjects and more: https://training.ti.com/ti-precision-labs-ultrasonic-sensing-overview?context=1139747-1139746-1147829-1147765

    Best,

    Isaac

  • 0 in reply to Isaac Lara
    Prodigy 100 points

    Thanks Isaac,

    the bistatic will reduce the blind range to almost zero it says. in terms of your products, if I get the  BOOSTXL-PGA460,  can I run it  in bistatic mode or the device software only support the monostatic configuration? should I also purchase the transducer with higher fc ( up to 480K) to get the lower blind range and higher resolution?

  • +1 in reply to Zeinab Ramshani
    TI__Mastermind 23045 points

    Hey Zeinab,

    Yes the reduction is essentially to zero, but you will see some switching noise when plotting the data from the GUI. I have not tested as low as 5cm but have been able to get 9cm with no issues. The BOOSTXL-PGA460 is capable of running in bistatic mode you can check this FAQ on how to properly set this up: www.ti.com/.../slaa733.pdf

    The software requires no modifications. The PGA460 comes with a 58kHz transducer that I have been able to get to measure as low as 15cm-17cm in monostatic so bistatic might yield the necessary results. Typically higher frequencies will have a lower ringing decay time than lower frequency transducers but higher frequency transducers do not operate well in air coupled applications. So make sure to find a balance between good signal transmission and high resolution.

    If you need a high resolution system then perhaps increasing the frequency might be necessary, in order to calculate resolution you can use this formula: Resolution = (1/frequency)*speed of sound

    Best,

    Isaac