Ch 7: Range Equation

Question 1

The elapsed time from pulse creation to pulse reception is called the…

Answer 1

go-return time or time-of-flight.

Question 2

Time-of-flight and depth are ___ related.

Answer 2

directly. The greater the depth imaged, the longer the time-of-flight.

Question 3

1.54 mm/microseconds x go-return time (microseconds) divided by 2 =

Answer 3

depth (mm)

Question 4

For every 13 microseconds of go-return time, the object creating the reflection is ___ deeper in the body.

Answer 4

1 cm

Question 5

When a pulse’s time-of-flight is 26 microseconds, the reflector is how deep?

Answer 5

2 cm

Question 6

When a pulse’s time-of-flight is 39 microseconds, the reflector is how deep?

Answer 6

3 cm

Question 7

Since a pulse travels to the reflector and back to the transducer, the total distance that a pulse travels is ___ the reflector depth.

Answer 7

twice

Question 8

imaging depth (cm) x 13 microseconds/cm =

Answer 8

PRP (microseconds)

Question 9

PRP is ___ related to the maximum imaging depth.

Answer 9

directly. The greater the depth, the longer the PRP.

Question 10

If the depth is 10 cm, the PRP is…

Answer 10

130 microseconds. (10 x 13 microseconds)

Question 11

If the depth is 5 cm, the PRP is…

Answer 11

65 microseconds. (5 x 13 microseconds)

Question 12

PRF is ___ related to maximum imaging depth.

Answer 12

inversely. The greater the depth, the lower the PRF.

Question 13

77,000 cm/s divided by imaging depth (cm) =

Answer 13

PRF (Hz)

Question 14

If the depth is 7.7 cm, the PRF is…

Answer 14

10,000 Hz. (77,000/7.7 = 10,000)

Question 15

If the depth is 15.4 cm, the PRF is…

Answer 15

5,000 Hz. (77,000/15.4 = 5,000)