本机前置放大器位于主磁体腔内,前放电源置于二号机柜底部,先卸去连于前放盒上接收线圈的接头,从传导板上测量前放工作电压应为直流15伏,将一台高频信号发生器的发射频率调到主磁场的谐振频率 f_0(f_0=42.58×B_0,B_0是用高斯计测出的主磁场强度),发射1毫伏的射频信号输入到前放, The local preamplifier is located in the main magnet cavity. The front discharge source is placed on the bottom of the No. 2 cabinet. The connector connected to the receiving coil on the front release box is first unloaded. The working voltage of the front release measured from the conductive board should be 15VDC, The transmitting frequency of a high-frequency signal generator is adjusted to the resonant frequency of the main magnetic field f_0 (f_0 = 42.58 × B_0, where B_0 is the main magnetic field strength measured by a Gauss meter), a 1-mV radio frequency signal is input to the pre-amplifier ,