User`s manual

101
4.4.15: Tri Parametric Filter
Application:
The Tri Parametric Filter consists of three adjustable IIR filter “substages”, connected in
series, which can be used for both peaking and nulling portions of the input signal’s
frequency spectrum. These substages can be configured independently, and are typically used
as precision notch filters, which perform nulling of the input signal at a specified Center Freq
over a specified width. The Boost/Cut parameter can be set to a negative value (-1dB to –
60dB) for this type of operation. However, a substage is also capable of peaking, which
allows a positive gain (Boost/Cut of 1dB to +16dB) to be placed at the Center Frequency over
the specified Width.
The filter input signal is first attenuated as specified by the Input Atten control, then the
attenuated signal flows sequentially through Substage 1, Substage 2, then finally Substage 3.
Controllable parameters for each seriesed substage include Center Frequency, Width, and
Boost/Cut.
Each substage can be independently bypassed using the individual Active buttons in order to
allow the user to more quickly and easily adjust each stage for optimum results. Simply click
in the substage that is to be adjusted while the other stages are clicked out; repeat this process
for each substage that is used. Also, an input Input Attenuation control allows the user to
quickly reduce the overall gain of the entire parametric filter without altering the overall
shaping function.
An bargraph Output Level indicator, as well as an independent Internal Overload indicator,
assists the user in avoiding output distortion by preventing the dynamic range limits of the
filter substages from being exceeded.
Figure 4-60 Tri Parametric Filter