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BOOSTXL-TUSS4470: Reflector shaping with BOOSTXL-TUSS4470

Part Number: BOOSTXL-TUSS4470
Other Parts Discussed in Thread: TUSS4470

Hi,

I'm writing to consult whether BOOSTXL-TUSS4470 can support the application of shaping the surface of a reflector (e.g. human hand). 

For the setting of the test, I'll put the reflector in front of the transducer, at the distance of about 30cm - 50cm. Pulse emitted from the transducer will be reflected back, by the surface of the reflector. Because the different points on the surface introduce different airtime delay (though could be as slight as millimeter level), it's possible to re-construct the shape of the reflector by looking at the multiple reflected pulse. 

To support this application, I think the device should be able to satisfy the following requirement:

1) short signal duration (less than 3us to separate the slight difference between the delayed reflected paths)

2) wide enough beamwidth (beamwidth limites the coverage at certain distance. Can this device cover the diameter of ~30cm at the distance of 30cm to 50cm?)

2) concurrent Tx and Rx. 

Appreciate any response! 

  • Hello Yanbo,

    Thank you for your question. I am a bit unfamiliar with this application so I will do my best to help you out.

    1. I assume that by this you are indicating signal transmission, unfortunately that is a problem that plagues ultrasonic measurements. Due to the nature of the technology when the transducer is excited it takes some time for the voltage to come back down which is referred to as ringing. There are methods to decrease the ringing period but I do not believe it is possible to keep it below 3us. Keep in mind that the ringing period depends on various things such as the amount of pulses transmitted, the voltage at which the transducer was excited to, and the frequency of the transducer itself can also have an effect. The ringing can be overcome by using more than one transducer, there is more on that below.

                                                                                    

    2. The beam width of field of view is dependent on the transducer attached to the device, the transducer that comes with this EVM is the PUI Audio UTR-1440K-TTR, a 40kHz transducer with ~70 degrees field of view. The TUSS4470 only provides the capabilities to drive a wide variety of transducers so if this one does not meet your specifications you are free to swap it for something that does.

    3. The TUSS4470 supports both monostatic (one TX/RX transducer) and bistatic (one dedicated TX and one dedicated RX transducer) topologies. Keep in mind that when a transducer is bursting then it cannot actively receive at the same time because the input will be saturated, hence why there is the bistatic solution that has one dedicate transmitter and one dedicate receiver. This will greatly reduce the ringing period if not eliminate it (possible switching noise if they are on the same device)There is a picture below for reference:

                                                                       

    Hopefully this answers the questions you may have!

    Best,

    Isaac

  • Hi Issac,

    Thanks a lot, for your detailed explanation. 

    It seems the bistatic mode can support simultaneous Tx and Rx, so that to to shape the reflector's surface. 

    But still two questions:

    1) what is the maximum sampling rate of the ADC? 

    2) I think 40 kHz transducer is not enough for my application, I need the transducer to be at leave 500 kHz, do you think BOOSTXL-TUSS4470 can support such transducer?

    Best,

    Yanbo

  • Hello Yanbo,

    1) The ADC on the MSP4305529 that is used with the BOOSTXL-TUSS4470 is the ADC12, I could not find the maximum sampling rate for this ADC but the data sheet does state that the conversion rate is greater than 200-ksps. The rate depends on which resolution you have selected with the options being 8-bit, 10-bit, and 12-bit. They each require a different amount of ADC clock cycles (9, 11, and 13 respectively). If you still have questions about the max rate for this ADC I would post in on the MSP forum as they are better suited to answer this question.

    2) The TUSS4470 can support up to 1MHz transducers, the only problem that I do see is if you are going to be using this air coupled at long distances, higher frequency transducers do not have a long range at high frequencies, the signal tends to attenuate significantly. Typically a transducer in this frequency range might be used for water or gas applications.

    Best,

    Isaac