Exam PWD

Temporal Shaping
In order to make more accurate measurements of the blood velocity, the temporal pattern of the pulse is typically repeated. This will result in a narrower bandwidth of the transmitted pulse, which can make more accurate velocity measurements. The number of repetitions is determined by Pulse Repeat.
 * Pulse Repeat

Sine the PWD line is repeatedly scanned at a high repetition frequency (PRF), localized heat is deposited into the tissue. In order to meet the safety limits, the amplitude of the pulse should be reduced. The following voltage indexes determine how the amplitude will be adjusted for increased PRFs:
 * Voltage- HighPRF
 * Voltage- MedPRF
 * Voltage- LowPRF

Sequencing
The scan line on which the gate is located will be repeated in the sequence:
 * PW Line

When using the interrupted PWD duplex sequences, the ratio of PW scan lines to B-mode scan lines in the sequence is determined by:
 * Interrupt Ratio

The repetition period (and thus frequency) of the the scanning for the PWD scan line is determined by:
 * PRP