This unit of temperature is still used customarily in the United States.
Definition: 0° is the coldest temperature achieved by using an ice and salt mixture, and 100° is set at the temperature of the human body. On this scale, the freezing point of water turned out to be about 32 °F and the boiling point about 212 °F.
1°F equals 5/9 °C. To convert a temperature in °F to the Celsius scale, first subtract 32° and then multiply by 5/9. In the other direction, to convert a temperature in °C to the Fahrenheit scale, multiply by 9/5 and then add 32°. The unit was defined by the German physicist Fahrenheit.
See also Thermal Units Per Hour.
Different sound velocities in tissues are causing false distance artifacts.
Ultrasound beams can suffer multiple reflections or specular reflections away from the sensor, giving false distance readings.
(FFT) The fast Fourier transformation is a particularly fast and efficient computational method of performing a Fourier transformation, which is the mathematical process by which raw data is processed into a usable image.
The fast Fourier transform analyzer is a common device that performs spectral analysis in ultrasound instruments. In this case, it displays different quadrature Doppler frequencies or reflector velocities when a sample volume cursor is used along time. The Dopplerfrequency is proportional to the spectral reflectorvelocity.
See also Proportionality Constant, and Sampling Rate.