  In this paper, we develop the theory of chirp mixing. The working principle
is simple, given coupled homonuclear spins with offsets in range [-B, B], we
adiabatically sweep through the resonances. This achieves cross polarization
between the z magnetization of the coupled spins. We repeat this basic
operation many times with a supercycle to achieve appropriate mixing time. When
we sweep through the resonances, midway between the resonances of the coupled
spin I and S, the effective field seen by two spins is the same and hence they
precess at same frequency around their effective fields. This means the
coupling, which normally gets averaged due to the chemical shift difference is
no more averaged for a short time and we get mixing. In this paper, we develop
these basic ideas. By virtue of its design, the chirp mixing is much more
broadband compared to state of the art methods. The proposed methodology is
demonstrated on 13C mixing in a sample of Alanine.
