FW: Noise gate
Araya, Juan Carlos
Sat, 7 Feb 1998 11:21:17 -0500
A noise gate is a power level gate. If the input power level is high
enough, set by the user, the input is allowed through. The input signal
is composed of your desired signal (music, voice, whatever) and noise
(thermal, shot, whatever). When the signal is below the desired
threshold the input signal is not allowed through (using high isolation
switch, whatever). You can set the level of your noise to where you
perceive the noise signal is the major contributor to your input signal
power. This works great for Metal/Punk where little or no dynamics are
used. Music with limited dynamic range. Using a noise gate on music with
large dynamic ranges (Classical, Big Band, so on) may not be
appropriate. These are also called signal-to-noise enhancers in
communication systems. For signals with high dynamic range but limited
frequency spectrum maybe a system with adaptive filtering maybe
appropriate. A dynamic variable-bandwidth variable-center frequency
bandpass filters that pass only spectrum ranges that have the
appropriate power level. This can be easily done in the digital domain
using FFT algorithms and the proper digital processing software. Maybe
there are DSPs that have this already.
Then again I maybe totally wrong,
Funkily yours
Juano
jaraya@lucent.com