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