User`s manual

104
4.4.16: Inverse Comb
Application:
The Inverse Comb filter is used to indentify harmonically related noises (noises which have
exactly equally-spaced frequency components), such as power-line hum, constant-speed
motor/generator noises, etc., from the input audio. The filter response consists of a series of
equally-spaced slots. This filter is the exact opposite of the Comb Filter.
Adjust the Inverse Comb Frequency to the desired spacing between slots (also known as
"fundamental frequency"). Set the Harmonic Limit to the frequency beyond which you do not
want any more slots. Set the Attenuation to the amount in dB by which noise frequency
components are to be reduced.
Normally, the Enhance Harmonics option will be set to All, causing frequencies outside all
multiples of the Fundamental Frequency (within the Slot Limit) to be reduced However, certain
types of noises have only the odd or even harmonic components present. In these situations, set
the Enhance Harmonics option to either Odd or Even.
Figure 4-62 Inverse Comb Filter
Description of controls is as follows:
Fundamental Frequency:
Specifies fundamental frequency in Hertz of inverse comb filter.
Slots are generated at multiples, or harmonics, of this frequency.
Note: Inverse Comb Frequency changes whenever the System
Bandwidth setting is altered; if you change the System Bandwidth
setting, you will need to readjust the Inverse Comb Frequency for
any Inverse Comb Filters selected.