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54 Cards in this Set

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T or F
Compression is not operator adjustable?
False
What is the process of decreasing the differences between the smallest and largest echo amplitudes?
Compression
What is the ratio of the largest to the smallest amplitude or power that a system can handle?
Dynamic Range
T or F
Detection is an operator controllable function?
False
What is the conversion of echo voltages from radio frequency form to video form?
Detection
What passes a range of frequencies and rejects those above and below the acceptance bandwidth?
Bandpass Filter
Where does action originate?
Beam Former
What does a Beam Former consists of? 7 things
1. Pulser
2. Pulse Delays
3. Transmit/Receive Switch
4. Amplifiers
5. Analog-to-digital converters
6. Echo Delays
7. Summer
What produces electric voltages that drive the transducer, forming the beam that sweeps through the tissue to be imaged?
Pulser
What is PRF and what does it stand for?
1. THe number of voltage pulses sent to the transducer each second
2. Pulse Repetition Frequency
What directs the driving voltages from the pulser and pulse delays to the transducer during transmission and then directs the returning echo voltages from the transducer to the amplifiers during reception?
T/R Switch
What performs the conversion of the small voltages received from the transducer elements to larger ones suitable for further processing and storage?
Amplifier
What determines how much amplification is accomplished in the amplifier?
Gain Control
What equalizes differences in received echo amplitudes caused by different reflector depths? Three Names
1. Compensation
2. TGC
3. DGC
Longer path lengths result in what two things?
1. Greater attenuation
2. Later arrival times
The increase in gain with depth is commonly called the ____ slope bacause it is sometimes displayed graphically as a line with increasing deflection to the right.
TGC
What is the attenuation in soft tissue?
0.5 dB/cm-MHz
TGC is set by the ____ to achieve, on average, uniform brightness throughout the image.
Operator
Typical TGC amplifiers compensate for how many dB of attenuation?
60
What converts voltage from analog to digital form?
Analog-to-digital converters (ADC)
One that passes a range of frequencies and rejects those above and below the acceptance bandwidth?
Bandpass Filter
Conversion of echo voltages from radio frequency (RF) form to video form? Two names
1. Detection
2. Demodulation
T or F Detection is an operator controllable function?
FALSE
What converts digitized, filtered, detected, and compressed scan-line data into images that are processed prior to and following storage in image memory, all in preparation for presentation on the instrument display?
Image Processor
Signal and image processing done before echo data are stored memory?
Preprocessing
Holding and displaying one frame out of the sequence is known as what?
Freeze-frame
Storage of the last several frames acquired prior to freezing is what?
Cine-loop
What is known as a picture element?
Pixel
What is known as a binary digit?
Bit
The memory divides the image into pixels, typically of what two matrix's
1. 256 x 512
2. 512 x 512
Each binary digit in a binary number is represented in memory by a memory element, which at any time is in one of _____ states which is either _____ or ____.
1. Two
2. On
3. Off
A group of 8 bits is called a what?1024 bytes is called what?
1. Byte
2. Kilobyte
Common in ultrasound instruments today are what three bit memories?
6, 7, 8
To enlarge pixels what is used? Two names
1. Read magnification
2. Zoom
What type of memories are discrete rather than continous, which means that they can store only whole numbers in each pixel location?
Digital
Image processing accomplished after memory is called what?
Postprocessing
If it cannot be performed on a frozen image, it is ____ function. If it can be performed on a frozen image, it is a _____ function.
1. Preprocessing
2. Postprocessing
What are the three more common modes used? Hint: One letter word.
1. B-Mode
2. M-Mode
3. A-Mode
The display device used in each machine is what?
Cathode-Ray Tube (CRT)
The number of images presented per second is called the ____ of the display.
Refresh Rate
The brightness is proportional to what?
Echo Strength
The number of sonographic images entered into image memory per second?
Frame Rate
Red and Green mixed equally produce what color?
Yellow
Green and Blue mixed equally produce what color?
Cyan
Red and Blue mixed equally produce what color?
Magenta
Red, Green, and Blue mixed equally produce what color?
White or Gray depending on brightness
The ability of a display to distinguish closely spaced events in time and to correctly present rapidly moving structures?
Temporal Resolution
The PRF required is determined by what three things?
1. Number of focuses
2. Lines per frame
3. Frame rate
To avoid misplacement of echoes what must happen before the next pulse can be emitted?
All echoes from one pulse must be received
Range Ambiguity Formula states that the penetration multiplied by number of focuses multiplied by lines per frame must be less than or equal to what?
77,000
What display mode form presents depth versus time?
M-mode
A television display format has how many horizontal display scan lines?
525
Two fields make up what?
1 frame
How many times per second does it take for a picture to be updated?
30