Ch 14 - Pulsed Echo

2 functions of US system

transmission + reception

6 components of US system

Transducer, pulser/beam former, receiver, display, storage, master synchronizer

Transducer main job = convert ___ into ____ energy

electrical, acoustic

The PULSER controls the _____ of the transmitted sound wave (aka pulse)

strength

The _____ excites the PZT during transmission

pulser

___ power = ____ intensity

inc, inc

Pulser modes include (3 types)

continuous, pulsed single crystal, pulsed array

Pulser is also called a “_____ _____” in a pulsed array

beam former

The Pulser determines the ____

PRP

shallow imaging = ____ listening time = ____ PRP = ___ PFR = ______ Duty factor = ___ frequency

less, shorter, higher, higher, higher

Deep imaging = ____ listening time = ____ PRP = ___ PFR = ______ Duty factor = ___ frequency

More, longer, lower, lower, lower

PRP is determined by the image ____

depth

Beam Former helps to reduce _____ _____ artifacts caused by ______

side lobe, apodization

Apodization = _____ of pulse from each element differs from element to element

strength

Transducer Output is also called _____ ____ or _______

outlet power or power

Transducer Output is determined by the ____ of the PULSER

voltage

Output power affects the _____ of the _____ (part/entire) image

brightness, ENTIRE

_____ power = dec image quality

dec

_____ happens when you turn the power down

noise

_____ power = _____ signal-to-noise ratio

inc, inc

High signal-to-noise ratio = ____ quality image

high

Receiver improves ____ signals as they return to the transducer

weak

What are the 5 functions of the Receiver (abc order)

Amplification, Compensation, Compression, Demodulation, Rejection

Amplification = ____ the strength of ALL electoral signals

inc

Amplification is also called ______ and is _____ by the sonographer

gain, adjustable

Amplification happens during ______

reception

Compensation is another name for _____

TGC

Compensation helps w/ ______

attenuation

Compensation treats echoes diff based on the _____ they come from

depth

What should you adjust if you can’t see in the near field of your image? (TGC’s)

The top

The TGC curve

Compression allows us to see diff _____ of shades of ____

ranges, gray

Compression is also called “_____ ____”

Dynamic Range

Grey Scale map seen in question = _____ question

compression

Demodulation ______ (can/can’t) be adjusted

can’t

2 steps of Demodulation

Rectification, Smoothing

Rectification converts all ____ voltages to ____ (makes everything absolute value)

negative, positive

“Reject” component is similar to the “_____ _____” on Doppler

wall filter

“Reject” component is used to get rid of ____ lvl ____ in images

low, noise

“Reject” component ONLY affects ____ lvl echoes NOT ____ echoes

low, bright

“Reject” Component _____ (can/can’t) be adjusted

can

What is the only receiver function that is NOT ADJUSTABLE

Demodulation

if image is too bright, what should you do?

dec power

If image is too dark, what should you do?

inc gain/amplification