  A typical stellar mass black hole with a lighter companion is shown to
succumb to a chaotic precession of the orbital plane. As a result, the optimal
candidates for the direct detection of gravitational waves by Earth based
interferometers can show irregular modulation of the waveform during the last
orbits before plunge. The precession and the subsequent modulation of the
gravitational radiation depends on the mass ratio, eccentricity, and spins. The
smaller the mass of the companion, the more prominent the effect of the
precession. The most important parameters are the spin magnitudes and
misalignments. If the spins are small and nearly aligned with the orbital
angular momentum, then there will be no chaotic precession while increasing
both the spin magnitudes and misalignments increases the erratic precession. A
large eccentricity can be induced by large, misaligned spins but does not seem
to be required for chaos. An irregular precession of the orbital plane will
generate irregularities in the gravitational wave frequency but may have a
lesser effect on the total number of cycles observed.
