Range Equation Ch 7

Question 1

what is time-of-flight? AKA?

Answer 1

time needed for a pulse to travel to and from the transducer and the reflector. AKA go-return time; round trip time

Question 2

what is time-of-flight used for?

Answer 2

measured so we can determine reflector depth

Question 3

since the average speed of sound in soft tissue is known (_______), the time-of-flight and ____________ in the body are ________ _________.

Answer 3

1.54 km/sec; distance that sound travels; directly related.

Question 4

what is the 13 microsecond rule?

Answer 4

in soft tissue, every 13 us of go-return time means the reflector is 1 cm deeper in the body

Question 5

the time-of-flight is increased by a factor of what?

Answer 5

2

Question 6

A sound pulse travels from the transducer to “point D” reflects off and returns to the transducer in 130 us. How deep is point D?

Answer 6

10 cm from transducer. bc for each 13 us the reflector is 1 cm deeper

Question 7

A sound pulse emitted from a transducer travels in an US phantom, reflects off of “point A” and returns to the transducer in 52 us. How deep is point A? what is the total distance that the pulse traveled?

Answer 7

4 cm deep; total distance of 8 cm ( 4cm in and 4 out).

Question 8

when we know speed of sound in the medium, there is a fixed relationship bw which variables?

Answer 8

time-of-flight and distance

Question 9

a sound wave is created by a transducer, reflects off of an object and returns to the transducer. the depth of the reflector is 10cm. Round trip time is 2 secs. what is the speed of sound in the medium?

Answer 9

10cm/s; bc speed= dist/time; here total distance= 20 cm and total time is 2 sec. 20/2= 10cm/s

Question 10

speed=

Answer 10

distance/time