Abstract
Free nuclear induction technique is widely used in measuring weak magnetic field. In the socalled Packard-Varian method, it is the problem how the design of the polarizing coil relates to the S/N ratio and how the transfer of the polarizing coil from the polarizing power supply to the amplifier relates to keep the coherency of the magnetization. This is the report along this line in the experimental and theoretical aspects. The experiment has been carried out in the earth's field, but extension to the higher field may be secured by the theoretical consideration given in this paper. The various results described in the report may present the general idea to design and construct a proton magnetometer of proper performance.
