• Determines time between electrical spikes (PRP)

PRP and PRF are (a)   related

Pulser determines the (a)  

• output gain, acoustic power, pulser power, energy out put, transmitter output are synonyms for (a)  

Transducer output is determined by the (a)   from the pulser. Piezoelectric crystal vibrates with a magnitude related to pulser voltage

The (a)   affects the brightness of the entire image

The (a)   can be adjusted by the sonographer

• When (a)   changes, every pulse transmitted to the body changes

When the (a)   changes, all reflections from structures in the body also change

When the (a)   changes, the brightness of the entire image changes.

Increasing ___ ___ improves signal-to-noise ratio

(a)  

Excessive output (a)   axial resolution

Considering transducer output, thermal index and mechanical index are both associated with (a)  

When amplification is increased, the electronic signals in the receiver are boosted, and the image will be (a)  

Persistent disturbance that blurs a signal

(a)  

It fills images with low level undesirable echoes

(a)  

Comparison of the meaningful signal in an image compared to the amount of noise

(a)  

High s/n ----> Image of (a)   quality

Low s/n --> (a)   image quality

If the transducer output is low --> (a)   signal to noise ratio

If transducer output is increased --> (a)   signal to noise ratio

Part of the transmitted that receives electrical spikes and distributes them to the crystal of the array transducer

(a)  

It coordinates the signals to optimize transmission of the sound beam

(a)  

It adjusts electrical signals to reduce lobe artifacts (anodization) [We will learn more about this in the lecture on artifacts]

(a)  

• It receives time delays for dynamic receive focusing.

• It controls the dynamic aperture (# of PZT used during reception and transmission).

• Easy, faster updates (software programming)

• Stable system

• Versatile

• Transmit-receive regulator

• Transmit: high voltages

• Receive: low voltages

• Protects the system by handling voltages appropriately

The signals returning from the transducer are extremely weak

(a)  

The receiver boosts the strength of these signals, processes them

     and prepares them for display

(a)  

Amplification (receiver functions) step (a)  

Compensation (receiver functions) step (a)  

Compression (receiver functions) step (a)  

Demodulation (receiver functions) is step (a)  

Rejection (receiver functions) step (a)  

What is another name for amplification;

(a)  

The ratio of the output electrical signal strength to the input of the electrical signal strength of the amplifier

(a)  

Increasing overall gain (a)   create an image with uniform brightness.

Typical values are 60 dB to 100 dB

(a)  

Used to create image of uniform brightness from top to bottom.

(a)  

Since attenuation is strongly related to path  length, echoes returning from great depths have (a)   amplitudes than those returning from shallow depths

Compensation makes an image equally (a)   at all depths

Less attenuation

Less TGC needed

(a)  

Higher attenuation

More TGC required

(a)  

The first arrow points to the:

(a)  

The second arrow points to:

(a)  

The third line points to:

(a)  

The fourth arrow points to the:

(a)  

The fifth arrow points to:

(a)  

This shows the (a)   curve

Reducing the total range, the smallest to the largest signal.

(a)  

Keeps signals within the operating range of the system's electronics and the gray scale within the range of what the human eye can see.

(a)  

Compression is Accomplished (a)   altering the

relative relationships between voltages; largest stays largest, smallest remains smallest.

Compression (a)   the dynamic range of the signals

It changes the electrical signals within the receiver into a form that fits the TV screen or cathode ray tube (CRT)

(a)  

All negatives voltages are converted to positive voltages. Eliminates negative voltages

(a)  

Also know as enveloping or smoothing process.

(a)  

It controls whether low-level grayscale echoes will appear on the displayed image

(a)  

Threshold and suppression are other names for:

(a)  

It allows the system to use only high frequency reflection to display the superficial portion of the image.

(a)  

Higher frequency --> (a)   axial resolution

Lower frequency are used to display

deeper portions. At this level, higher frequencies have disappeared due to attenuation

(a)  

Affects image brightness by adjusting the strength of the sound pulse sent to the tissues.

(a)  

When the pulse is more powerful, all of the returning echoes from the body are stronger, and the image is (a)  

When the image is too bright due to high output power, the lateral and longitudinal resolution (a)  

Affects image brightness by changing the  amplification of the electronic signals after returning to the receiver.

(a)  

As Low As Reasonably Achievable

(a)  

Creates and controls electrical signals sent to the transducer that generate sound pulses. The (a)   determines the amplitude, PRP, and PRF

The (a)   determines the firing delay patterns for phased array systems

Transforms the electrical signals from the transducer

(a)  

Presents processed data.

(a)  

Archives the ultrasound studies

(a)  

Maintains and organizes the proper timing and interaction of the systems components

(a)  

Changes in (a)   modify the brightness of the entire image

Low voltage of the PZT, (a)   image

Higher pulser voltage, (a)   image

When transducer output is (a)   , noise is more likely to degrade the image

When a sonographer increases output power, the signal to noise ratio (a)  

The (a)   protects sensitive electrical components in the receiver from the high voltages created during transmission

(a)   is the process of improving the quality of a signal BEFORE it is amplified. This occurs as close to the active elements as practical

(a)   are specially designed to prevent electrical noise from contaminating the tiny electrical signals created by the transducers active elements during reception

At superficial depths, reflections undergo a small, constant amount of compensation called the:

(a)  

The depth at which variable compensation begins is known as the:

(a)  

In the region of the (a)   , compensation corrects for the effects of increasing attenuation that result from increasing path length

At the depth of the (a)   , reflections are maximally compensation by the ultrasound system