User`s manual

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4.4.6: Bandstop Filter
Application:
The Bandstop filter is used to decrease the energy level (lower the volume) of all signal
frequencies above a specified Lower Cutoff Frequency and below a specified Upper Cutoff
Frequency. The signal region between the Lower Cutoff Frequency and the Upper Cutoff
Frequency is called the stopband region. The Bandstop filter is useful for removing in-band
noise from the input signal.
The Lower Cutoff Frequency is usually set below the frequency range of the noise, while the
Upper Cutoff Frequency is set above the frequency range of the noise. While listening to the
filter output audio, the Lower and Upper Cutoff Frequencies can be incrementally adjusted to
achieve maximum elimination of noise while minimizing loss of voice.
The amount of volume reduction in the stopband region can further be controlled by adjusting
the Stopband Attenuation setting (maximum volume reduction is 60dB). The slope at which
the volume is reduced from normal (at each Cutoff Frequency) to the minimum volume
(specified by Stopband Attenuation) can also be controlled by adjusting the Transition Slope
setting.
Description of controls is as follows:
Lower Cutoff Specifies frequency in Hertz below which no
Frequency: signals are attenuated. Frequencies between this cutoff and the Upper Cutoff
Frequency are attenuated. Minimum Lower Cutoff Frequency is 0 Hz, while
the maximum Lower Cutoff Frequency is 10 Hz below the Upper Cutoff
Frequency. Lower Cutoff Frequency can be adjusted in 1 Hz steps.
NOTE: The Lower Cutoff Frequency can never be set higher than 10 Hz
below the Upper Cutoff Frequency.