[Elecraft] Subtractive noise reduction

[John Kountz]

Folks,
This technique is integral to almost any disc record restoration software.  It is used most often to remove scratches and related damage from disc recordings.  Basically it consists of sampling the unrecorded lead in or 'quiet' interludes on the disc to provide a spectral profile of the noise to be dealt with, inverting that profile using it as a 'look ahead' filter  through which subsequent audio engraved on the disc is passed.  It is entirely conceivable that a similar technique could apply dynamically to material off the air proceeding the incoming 'signal' and applied as that 'signal' is received.  Just another subroutine.
73,
John Kountz WO1S, T6EE