PGA460: Measurement result is not good

Hello Cherry,

Thanks for posting to the sensing forum!

Let me help address the customers questions:

1) What does a burst mean in a run command? Could you help elaborate more? What is the difference between preset 1 burst/listen and listen only? What will be the difference in the measured results?

• The burst in a burst command essentially indicates that the PGA460 will generate a signal to excite a transducer connected to the device via the OUTA and OUTB pins. The difference between the burst and listen compared to the listen only command is that in the listen only command the device will not generate a signal to excite the transducer on the OUTA and OUTB pins. This is used in the cases when you have two devices in a bistatic configuration with device one that generates the signal and one that just listens for the echo. Like the one shown in section 4.1 of this document: https://www.ti.com/lit/an/slaa732a/slaa732a.pdf. The benefit of using a setup like this is that the RX transducer does not have a blind zone where it is saturated during the burst time. Which allows users to make smaller measurements than they could if they were only using a single transducer.

2) Customer refers to the software development guide and uses preset 1 burst/listen commands, the measured echo results are very small. Using preset 2 burst/listen commands, the measured echo results are large enough to exceed 11.2 m. Changes in the distance of the obstacle object, with little change in the test results. What could be the cause?

• The presets are essentially two configurations that could be setup on the device. In some cases some users may use one preset for making short measurements while the other preset could be used to make further measurements. There is essentially no difference to the presets the only differences come in how the customer configures them. If they are getting very small results when  using preset 1 compared to preset 2 my assumption is going to be that they have configured them differently, there are some settings that significantly can alter your sensing distance. 
• Some of the settings they can change per preset: number of pulses sent during a burst, record length, threshold configurations, digital gain. I have included images from the GUI in case they are using that and would like to configure these settings.

Best,

Isaac