Describing Pulsed Waves

Question 1

5 pulsed wave parameters

Answer 1

pulse duration, spatial pulse length, pulse repetition period, pulse repetition frequency, duty factor

Question 2

True of False: Pulsed Waves are required to produce images

Answer 2

true

Question 3

What is a pulse?

Answer 3

a collection of individual cycles traveling together

Question 4

Transmit time is also known as?

Answer 4

“On” time or talking time

Question 5

Receive time is also known as?

Answer 5

listening time or “off” time

Question 6

Define pulse duration

Answer 6

The time from the start to end of a pulse; single transmit time

Question 7

Normal values for PD

Answer 7

0.5-3.0 microseconds

Question 8

What is PD determined by?

Answer 8

the source

Question 9

Can the PD be adjusted by the sonographer?

Answer 9

No

Question 10

How many pulses must a pulsed wave have?

Answer 10

at least 2

Question 11

PD is ________ proportional to number of cycles in a pulse

Answer 11

directly

Question 12

PD is _______ proportional to period

Answer 12

directly

Question 13

PD is ________ proportional to frequency

Answer 13

inversely

Question 14

True or false: Short duration pulses create better images

Answer 14

True

Question 15

Define Spatial Pulse Length

Answer 15

the distance a pulse occupies in space from start to end

Question 16

Units for SPL

Answer 16

distance (mm)

Question 17

Typical values for SPL

Answer 17

.1-1.0 mm (in soft tissue)

Question 18

SPL is determined by?

Answer 18

the source and the medium

Question 19

Is the SPL adjustable by the sonographer?

Answer 19

No

Question 20

SPL is ________ proportional to number of cycles in the pulse

Answer 20

directly

Question 21

SPL is ________ proportional to wavelength

Answer 21

directly

Question 22

SPL is _______ proportional to frequency

Answer 22

inversely

Question 23

True or False: Pulses with a longer SPL create better images

Answer 23

False; shorter SPL

Question 24

Define Pulse Repetition Period

Answer 24

the time from the start of one pulse to the start of the next pulse; includes one talking and one listening time

Question 25

Units for PRP

Answer 25

time (microseconds)

Question 26

Typical Values for PRP

Answer 26

100 microseconds to 1 millisecond

Question 27

PRP is determined by?

Answer 27

the source

Question 28

Is PRP adjustable by the sonographer?

Answer 28

Yes; adjust depth of view

Question 29

PRP and depth are _______ related

Answer 29

directly

Question 30

When the sonographer adjusts PRP, are they adjusting the transmit or receiving time?

Answer 30

receiving time

Question 31

Define PRF

Answer 31

the number of pulses transmitted into the body each second

Question 32

Units for PRF

Answer 32

hertz

Question 33

Typical Values for PRF

Answer 33

1,000 to 10,000 hertz

Question 34

The PRF is determined by?

Answer 34

the source

Question 35

Is the PRF adjustable by the sonographer?

Answer 35

yes; adjust depth

Question 36

PRF and depth are _______ related

Answer 36

inversely

Question 37

At 2cm depth, the PRF is ______

Answer 37

high; system waits less time to create new pulse

Question 38

At 20 cm depth, the PRF is _____

Answer 38

low; system waits longer to create new pulse

Question 39

PRP and PRF are _______ related and are ________

Answer 39

inversely; reciprocals

Question 40

PRF x PRP = ?

Answer 40

1

Question 41

Define Duty Factor

Answer 41

the percentage of time a system transmits a pulse

Question 42

Typical values of DF

Answer 42

.002-.005; .2-.5%

Question 43

To create images, duty factor must always be ______

Answer 43

less than 100%

Question 44

DF is determined by?

Answer 44

the source

Question 45

Is the DF adjustable by the sonographer?

Answer 45

Yes; adjust depth of view

Question 46

DF and depth are _________ related

Answer 46

inversely

Question 47

How much time does the system spend transmitting? Receiving?

Answer 47

.2%; 99.8%