
Magnetic Field Measurements and Their Applications 375
in the receiver coil is induced FID signal. Information
about properties of the investigated substance usually
brings the length of magnetization vector and the relax-
ation time T
2
(see Table 2.10). Because the frequency
range of a sinc signal is extended to innity, it is limited
in time by reverse change of the gradient signal.
Unfortunately, due to magnetic eld nonuniformity
and other reasons (Kuperman 2000, Vlaardingerbroek
and den Boer 2004), the response signal is decreasing
faster according to T
2
*
relaxation time (instead of T
2
time). To detect real T
2
relaxation time