Test 2 Flashcards
What are the 3 variables of the range equation?
- Time
- Distance
- Speed
What is the time from a pulse being sent to a pulse being recieved called?
Time of flight.
When is time of flight short? in superficial or deep structures?
Superfical.
The time-of-flight is directly related to what?
Depth.
What is the range equation?
Depth (mm)=(1.54 mm/usec x time-of-flight (us))/2
For every 13us of time-of-flight, the object creating the reflection is how much deeper?
1cm
What is the reflectors depth if a pulses time-of-flight is 26 us?
2 cm deep.
How do you find period?
1/f
How do you find the frequency?
1/t
What is PRP?
It is the time from the start of one pulse to the start of the next pulse.
When the depth of view is shallow, what type of PRP would it have?
Short.
When the depth of view is deep, what does it PRP look like?
Long.
What is the equation for PRP?
PRP=imaging depth (cm) x 13us/cm
What is PRP directly related to?
Maximum imaging depth.
When the depth of view is shallow, how is the PRF?
High.
When the depth of view is deep, PRF is like?
Low.
What is the equation for PRF?
PRF (Hz)= 77,000 cm/s/image depth (cm)
PRF is inversely related to what?
Imaging depth.
What is “duty factor”?
It counts how long a pulse is on duty.
What is the equation of Duty Factor?
DF %=(Pulse duration/PRP) x 100
What are the advantages of a Pencil probe/Pedof probe?
- Sensitive
- Inexpensive
- Inexpensive electronics necessary
What are the disadvantages of the Pencil probe/Pedof probe?
- No image
- Manual steering
- Fixed focus for transmiting and receiving.
Describe a Mechanical transducer: single element
- First generation (static scanners)
- Mechanical steering-single element.
What are the advantages to a mechanical transducer: single element?
- 2D image
- Wide field
What are the disadvantages to a Mechanical transucer: single element?
- No steering
- Fixed transmitig and recieving focus.
- Parts wear out/break,
- Motion artifacts
What are the advantages to a Mechanical transducer: Annular array?
- 2D
- Variable focus (lateral, elevation)
- Wide field
What are the disavantages to a Mechanical transducer: Annular array?
- Motion artifact
- Parts wear out
- Limited temporal resolution
What are the advantages of a Linear Switched Array?
- 2D
- Electronic switches
- Wide field.
What are the disadvantages of the Linear Switched Array?
- No steering
- Fixed focus (lateral, elevation)
What is the Linear Phased Array associated with?
Hugen’s principle.
What are the advantages of the Linear Phased Array?
- 2D image
- Electronic pulsed sequencing
- Variable focus (lateral)
- Steering.
What are the disadvantages of the Linear Phased Array?
- Expensive
- Fixed focus (elevation)