We have re-analyzed two EXOSAT Medium Energy observations during part of the 1984 X-ray outburst of the black-hole candidate transient system 4U 1630 - 47 .
One observation ( May 10 ) shows fast timing properties ( on timescales shorter than \sim 250 s ) typical of those of other black hole candidates in their high states .
The power-spectrum shows a power law with index \sim 0.7 and fractional rms amplitude ( 0.001–1 Hz ) of \sim 2 % .
Another observation , obtained one month earlier ( April 11 ) , shows different fast timing behavior .
The power spectrum of this observation can be described by a power law with index \sim 1.5 and fractional rms amplitude ( 0.001–1 Hz ) of \sim 7 % .
This is inconsistent with the behavior during low , high or very high states known to occur in most of the black hole candidates .
Instead , the timing properties resemble those recently reported from ASCA observations of the superluminal black-hole candidates GRS 1915+105 and GRO J1655 - 40 ( X-ray Nova Sco 1994 ) .
This timing behavior may represent a new state of black hole candidates .

In addition , the X-ray spectra of the three sources show similar properties .
Since GRS 1915+105 and GRO J1655 - 40 exhibit superluminal jets , we propose that 4U 1630 - 47 is also a relativistic jet source .