  We report on the detection with RXTE of variable high frequency features in
the power spectra of the black hole candidate 4U 1630-47 during its 1998
outburst. We find high frequency features during the rise and the early decay
of the outburst in the range of 100-300 Hz. The features are usually found to
be broad, and have rms amplitudes of 2-8; their frequencies are correlated with
count rate and anti-correlated with spectral hardness. Also, for the first time
twin high frequency features are detected simultaneously, with a ratio in
frequencies consistent with 1:4. Although some of the high frequency features
are less coherent and stronger than found in other black hole sources, we show
that they behave very similar to the high frequency features found in for
instance XTE J1550-564.
