  We examine the characteristics of the pi/2 pulse for simultaneously rotating
two spin species of different gyromagnetic ratios with the same sign. For a
pi/2 pulse using a rotating magnetic field, we derive the equation relating the
frequency and strength of the pulse to the gyromagnetic ratios of the two
particles and the strength of the constant holding field. For a pi/2 pulse
using a linear oscillatory magnetic field, we obtain the solutions numerically,
and compare them with the solutions for the rotating pi/2 pulse. Application of
this analysis to the specific case of rotating neutrons and 3He atoms
simultaneously with a pi/2 pulse, proposed for a neutron electric dipole moment
experiment, is also presented.
