MSP430FR6043: I don't know what is the start time and end time of Tprooop and Toffset here respectively

Thanks Susan.

Did you mean that Tprop is the time from the 1st pulse sent to the nth lobe received, and Toffset is the time from when the ADC starts to acquire to the nth lobe received? 

Tprop - Toffset is the time from the first pulse sent to the start of ADC acquisition, which should be a fixed period of time.

The customer thinks that if this is the case, the subtraction in the formula is meaningless, because this is a fixed value.

Could you please explain this?

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Thanks & Regards

Yale

Susan,

Yale Li 李耀先 said:

Tprop is the time from the 1st pulse sent to the nth lobe received, and Toffset is the time from when the ADC starts to acquire to the nth lobe received

Shouldn't this be a fixed time? This is my customer's understanding, is it correct?

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Thanks & Regards

Yale

What my customer means is that Tproop - Toffset coincides with the time when ADC is turned on and captured. This time(ADC is turned on and captured) is fixed, so Tprooop - Toffset is fixed.

This is the point we don't understand.

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Thanks & Regards,

Yale

Hello,

All of these variables are user adjustable, so if they aren't changed they should remain the same. Adjusting these values in the software should help calibrate the device. Is that what you are referring to?

Thank you,

Susan

Susan,

However, the absolute time of flight of ultrasonic wave in liquid may change with the change of temperature and density, so the absolute time of flight changes. But calculating the changing absolute time-of-flight with a fixed Tprooop - Toffset is contradictory. I can't understand the point here.

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Thanks & Regards

Yale

Hi Susan,

That is to say, the user first sets an approximate value for Toffset, and then the algorithm adjusts Toffset according to the threshold (such as 10%), so as to obtain an accurate value and locate the first lobe, right?

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Thanks & Regards

Yale