Before revision: where = resulting noise temperature referred to the input = noise temperature of the first component in the cascade = noise temperature of the second component in the cascade = noise temperature of the third component in the cascade = power gain of the first component in the cascade = power gain of the second component in the cascade Therefore, the amplifier chain can be modelled as a black box having a gain of and a noise factor given by .
After revision: where = resulting noise temperature referred to the input = noise temperature of the first component in the cascade = noise temperature of the second component in the cascade = noise temperature of the third component in the cascade = power gain of the first component in the cascade = power gain of the second component in the cascade Therefore, the amplifier chain can be modelled as a black box having a gain of and a noise figure given by .