Acquisition

The Basics

Data collection requires four pieces of equipment:

1. an Analog-to-Digital Converter (A/D) board,
2. a Pulser/Receiver (P/R),
3. an ultrasonic transducer,
4. a standard desktop or laptop computer to display the resulting information.

In a data collection, the P/R is triggered (often by a signal from the A/D board) which sends a burst of electricity to the ultrasonic transducer. This excites the transducer, which generates a burst of ultrasound. The returning ultrasound is sent back to the P/R, which sends the resulting waveform to the A/D board. The A/D board turns the waveform into digital information, which is processed into Peak Amplitude and Time of Flight results.

The Collection Cycle

By continuously triggering the P/R while moving the transducer along an axis, we can generate results along a scan line. By stepping along a second axis after each scan line, a raster image of data is generated.

The trigger of the P/R is synchronized to the start of collection on the A/D board, so that the waveforms are always generated at the same point in time. In practice, this usually means that the A/D board itself sends the trigger to the P/R.

See Also: Triggering

Acquisition with a Phased Array

With a phased array device such as an Olympus FocusPX, The Pulser and A/D are combined in order to handle the complex interactions between the individual elements.