Excitation Voltage

What is the excitation voltage?

The voltage send from the pulser to the crystal.

What are the two methods for getting an excitation voltage?

1. DC spike voltage method (old single crystal technology)

2. AC spike voltage method (modern technology)

What is AC?

Alternating current.

Does AC have a frequency?

Yes.

What is DC?

Direct current.

Does DC have a frequency?

No.

What is the modern burst voltage method?

A method that uses short AC voltage bursts to generate pulses. (Has an excitation voltage)

How many cycles is the modern burst voltage method?

10-20 cycles.

What is the voltage with the modern burst voltage method?

Lower voltage of ~ 100 volts.

The AC voltage burst does what to the transducer?

Drives the transducer.

An AC voltage allows sonographers to do what?

Produce a pulse of ultrasound at a frequency they wish to produce.

The transmitted frequency of the transducer equals what?

The excitation burst frequency.

The modern burst voltage method is used with what?

Today’s broad bandwidth array transducers.

What is the excitation frequency also known as?

The driving frequency.

The frequency of the driving AC voltage is applied to what object inside the transducer?

The crystal.

The driving AC voltage can be used to do what?

Force the crystal to vibrate at a frequency different then the resonant frequency.

By changing the excitation frequency, the sonographer can do what?

Change the transmitted frequency from the transducer.

What is the transmitted frequency also known as?

The frequency of the ultrasound pulse.

The transmitted frequency used to be equal to what?

The resonant frequency of the crystal. Now it can be different.

What is the AC burst voltage mode?

A mode that allows us to select from a range of frequencies by simply pushing button. (The button changes the frequency of the driving voltage).