Audio Engineering

Digital Audio Production 609

and falls off rapidly after that. For most applications (audio included), simple low-pass
fi ltering of the digital maximal-length sequence results in white Gaussian noise, provided
that the breakpoint of the low-pass fi lter is well below the clock frequency of the register
(say 0.05 Fc to 0.1 Fc), that is, in the region where the spectrum of the digital noise is
constant. The analogue fi lter may be a simple 6-dB/octave RC circuit, but usually a
sharper active fi lter is desirable.

Reference

1. Brice, R. , Newnes Guide to Digital Television , Newnes , 1999.