低噪声放大器的必要性,不但表现在通讯方面,而且还用它从计算机的磁性装置如磁盘存贮器和磁带中读出数据。因为在数据的读出速度比较高时,读出头上的线圈匝数要很少,而且信号的电平也要接近典型的晶体管噪声电平,所以,为了保证性能无误差,晶体管噪声必须很小。 The need for low-noise amplifiers is not only reflected in communications, but it is also used to read data from computer magnetic devices such as disk storage and magnetic tape. Since the number of turns on the read head is small and the level of the signal is close to the typical transistor noise level at relatively high readout rates, the transistor noise must be small to ensure error-free performance .