Low noise amplifier is a very low noise factor amplifier, generally used as a high frequency
or intermediate frequency preamplifier of various radio receivers, and an amplifier circuit
of high sensitivity electronic detection equipment. In the case of amplifying weak signals,
the noise of the amplifier itself may interfere with the signal seriously, so it is hoped to
reduce this noise to improve the signal to noise ratio of the output. The performance of
the first low noise amplifier directly determines the sensitivity of a receiving system.