Before revision: is customarily taken to be room temperature, 290 K. The noise factor (a linear term) is more often expressed as the noise figure (in decibels) using the conversion: The noise figure can also be seen as the decrease in signal to noise ratio (SNR) caused by passing a signal through a system if the original signal had a noise temperature of 290 K. This is a common way of expressing the noise contributed by a radio frequency amplifier regardless of the amplifier's gain.
After revision: is customarily taken to be room temperature, 290 K. The noise factor (a linear term) is more often expressed as the noise figure (in decibels) using the conversion: The noise figure can also be seen as the decrease in signal-to-noise ratio (SNR) caused by passing a signal through a system if the original signal had a noise temperature of 290 K. This is a common way of expressing the noise contributed by a radio frequency amplifier regardless of the amplifier's gain.