Transducer's Voltages - what are they?

[flotulopex]

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Hello,

I've just started a project involving the use of a transducer. Never used transducers before...

It's technical data specifies DC Bias Voltage, AC Driving Voltage and Combined Voltage.

My understanding is as following and please, this is the purpose of this thread, correct me if I'm wrong (you are also allowed to correct my english ):
- DC Bias Voltage is the constant polarized (+/-) applied voltage to the transducer in "receive" mode;
- AC Driving Voltage is the voltage used when the transducer is in "emitter" mode;
- Combined Voltage is... is what?

NB: if it may help, the transducer's datasheet is here: http://www.acroname.com/robotics/parts/R134-600.pdf