This thesis addresses the general problem of minimizing the power
dissipated by high-speed digital superconductor RSFQ circuits with
particular application to the design of a unique physical device, an
ultra-wide-band ( 
) ultra-low-power ( 
per
channel) all-digital autocorrelator for radio astronomy
applications. The purpose of this chapter is to review the main ideas
and current state of RSFQ technology as well as the basic methods and
existing devices of autocorrelation spectroscopy in radio astronomy.