Quiz 2 Review Flashcards
What is the main advantage to the addition of the analog scan converter?
Made grey scale imaging possible
A system with timed gain compensation controls (TGC) allow the operator to compensate for attenuation of the sound beam during transmission of the sound beam T/F?
False
In this modified box diagram of signal processing, which box below represents what?
- Pulsed
- Receiver
- ADC
- DCD
Why is a digital memory ore advantageous than the traditional analog scan converter?
Digital is more stable
An ultrasound system display, pulse, amplifier and reject can all be expressed in decibels T/F?
True
Which of the following accurately defines dynamic range?
- Compensation
- The brightest returning echo
- The average of frames for smoothing
- The ratio between the highest and lowest signals
D) The ratio between the highest and lowest signal
Which of the following controls would allow a sonographer to adjust the compression level of a receiver?
Dynamic range
What two things are assigned to a signal when it is stored in a digital scan converter?
Binary number and An address
List the components of the receiver
- Gain
- Compensation
- Compression
- Demodulation
- Rejection
What does a digital scan converter store to be read later for display?
- Electrical charges
- Numbers
- Voltages
- Echoes
Numbers
The analog to digital converter changes _____ to _______
Voltages, numbers
What process converts the radio frequency signal from the memory into the analog video signal needed to display?
Demodulation
Which of the following binary numbers would represent the decimal number 23?
- 010110
- 011000
- 010111
- 110111
- 010111
Which of the following conditions would result in greater nano speed delays occurring in the echo delay circuit of the beam former?
- An echo returning from a deeper depth
- An echo returning from a shallower depth
- An echo returning from mid range depth
- An echo returning from a shallower depth
(Because the object is so close, to make sure that there is a delay we must fire more constantly)
When writing frames of data to cathode ray tube, what process is used to help reduce the chance of flicker?
- Progressive scanning
- Raster format
- Persistence
- Interlacing
Interlacing
What is a sonographer hoping to improve by compressing the dynamic range?
Contrast resolution
What two processes are executed to complete demodulation of a signal?
Rectification and smoothing
Hat defines the processing of a group of echoes prior to being written to the systems memory?
Pre-processing
What process involves the assignment of a value to a pixel when no echo data was received to improve the appearance of the image?
Interpolation
What three colours re used in a cathode ray tube to allow it to display a multitude of colours on the screen?
Red, Green, Blue
How many shades of gray is a system with bit depth of 7 able to display?
128 (2^7)
What decimal number is represented by the binary number 001100111
103
What is the resolution in mm/pixel with a 512 x 512 matrix scanning to a depth of 5 cm?
0.1 mm/pixel
Ow else could a sonographer describe a system with a depth of 1?
Bistable
Interlaced raster scanning is accomplished by writing field data at a rate of 1 per seconds 30, T/F?
False
Which of the following systems would offer the best contrast resolution?
- 5
- 6
- 7
- 8
8 bit
What is a group of 8 bits called?
A byte
What Beamer former component prevents large amplitude voltages from damaging the sensitive circuitry?
Transmit/ receive switch
The reject function is set to improve the signal to noise ratio of the image? T/F?
True
Which pairings listed could be used to improve the memory/ display resolution of an ultrasound machine?
- Increase pixels and increase depth
- Decrease pixels and increase depth
- Increase pixels and decrease depth
- Decrease pixels and decrease depth
- Increase pixels and decrease depth
