To date, a growing number ( 
) of different large-scale ( 
Josephson junctions) digital RSFQ devices have been reported
to be fully operational at low frequency, but so far only a few of
them have been tested at speed. These include the 1024-bit shift
register [25], time-to-digital converter
[26] and, most notably, analog-to-digital converter
[27] built of 117 logic cells (1,778 Josephson
junctions) which was fully operational at 
and dissipated
of power. The digital autocorrelator (total of 1636
junctions) described in Chapter 
, was not fully
functional (3 out of 16 channels did not work due to fabrication
defects), but demonstrated basic functionality at clock speeds of up
to 
.