Theory of System Operation
This information is taken from the UE-1 manual.

When a scan is being performed, the system translates the sensor down the length of the rotating cylinder, while
pulsing the sensor at a user defined interval. The interval is set by using the pulses/revolution command in the
software. Since cylinder diameters can vary, setting a circumferential pulse resolution in pulses per inch would
result in a skew in the C-scan plot. By setting the pulse resolution by the number of pulses per resolution, this does
no occur. The user defined pulse resolution is controlled by the encoder on the R-axis motor. The encoder output is
input into the counter/timer board in the computer, and the encoder pulses counted. When the correct number of
pulses have been detected the meet the pulses revolution setting, the counter/timer board sends a trigger pulse to
the pulser/receiver to send a pulse to the transducer. The output trigger of the pulse/receiver is sent to the A/D
board, causing it to capture the transducer response. Each pulse is then stored into the computer memory, and
analyzed at the end of each scan, and the result displayed on the C-scan. The translation speed of the X-axis is
controlled by the rotational speed of the cylinder. This is automatically adjusted by the software, based on rotational
speed and scan index.