Review Quiz Flashcards
3 functions of the pulser
Generates the voltage pulses
Sets the PRF
Controls the power
How many cycles are produced by the electric voltafes
A cycle of A/V electrical voltage, producing 2/3 cycles/pulse
What determines the freq of the resulting ultrasound pulse
The freq of the voltage pulse/ transducer element thickness
Why are pulse delays required
For arrays, complicating sequencing and phasing operations
What is coded excitation
Uses a series of pulses and gaps rather than a single driving pulse to produce a scan line
What does the decoder do
Recognizes and dissassembles the coded sequence in the returning echoes and can stack up the individual pulses in the sequence to make a short, high intensity echo out of them
What function does coded excitation accomplish in B flow
It is the equivalent of having a much higher intensity driving pulse, or a much more sensitive recieving system. It can allow weak echoes to be imaged, so the echoes of the blood cells themselves can be visualized
What is a transmission channel
Each transmission element and its delays
Why are transmission channels required
More precise control over the beam characteristics
What is the maximum number of channels
The number of elements in the transducer
What does the transmit/receive switch do
Direct voltage pulses and the delays to the transducer during transmission and then directs echo voltages from the tansducer to the amplifier
What does the T/R switch protect
The sensitive input components of the amplifiers from the large voltage from the pulser
TGC corrects for
Tissue attenuation
Gain increases
All amplitudes
Analog is
Proportional
