User`s manual

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dynamic range from 0 to -70 dB.
When viewing the filter response on the display, the user can choose the
dynamic range of the trace. This selection is made using the drop-down
menu in the Filter Trace block. Because the filter can both attenuate
and boost frequencies, the trace grid does not have hard range limits.
Instead, the trace limits are automatically adjusted to “good” settings
based on the user-specified range and the filter response values. The
trace will always obey the user-specified range, but the minimum and
maximum values on the vertical axis will adjust as necessary to
accommodate the filter response values. The filter response trace reflects
the actual coefficients that are applied to the input audio to get the output
audio. This means that the trace will reflect the voice limits, output
shape, filter amount, operation mode, and the applied auto gain or
manual gain.
A marker is available to help identify the value of a specific point on the
trace. The marker, which looks like a set of crosshairs, can be placed
anywhere on the trace and its frequency (horizontal position) and
amplitude (vertical position) can be read just below the trace display.
The marker is available on both the audio and filter response traces.
Adaptation: The controls in this block are used to specify the adaptation rate of the
averager on which the ASIF is based
Adapt Button: When the green light is lit (and the button depressed), the ASIF is
adapting in response to incoming audio. When the light is unlit (and the
button unpressed), the ASIF response is frozen.
Clear Button: This button allows the user to re-initialize the ASIF response and restart
adaptation.
Note: After a Clear operation or after re-enabling adaptation, there will
be an adaptation period while the filter adapts to the current input signal.
The length of this adaptation period depends on the Adapt Rate control
setting.
Adapt Rate Control: This control allows the user to select the rate of adaptation for the
spectral average on which the ASIF response is based. The spectral
averager uses an exponential average of the form H
i+1
= (a)(X
i+1
) + (1-
a)(H
i
). The value shown in the display box corresponds to the averaging
constant a in the exponential average. The lower the adapt rate value,
the slower the filter will respond to changes in the input audio.
Note: “Fast response” sounds like a good thing, so it can be tempting to