This chop smooths or sharpens the input channels. It filters by combining each sample and a range of its neighbor samples to set the new value of that sample. Each filter type uses its own weighting factors for the neighboring samples. The Filter Width determines the number of neighbors to use.
This chop can filter both motion and sound, but other chops are more appropriate for filtering sound (see the Pass Filter
CHOP, Band EQ CHOP, and Parametric EQ
CHOP).
Parameters
Type | There are 7 types of filters. See manual for pictures of shapes. Gaussian | This filter has a Gaussian (normal or “bell” curve) shape that smooths the channel. It acts as a low pass filter. The wider the filter, the lower the cutoff frequency, resulting in smoother data. | Left Half Gaussian | This produces a lag on the channel. If the input channels represent values over time, this filter is seen as only using samples back in time from the current sample. For time-data, this is more realistic as you can’t look ahead in time. It has a half-bell shape. | Box | This filter is box-shaped, meaning that each neighbor sample it uses has the same weighting factor. It can produce unwanted steps in the output channel because the effect of the samples at the extremes of the filter don’t fade out as the window slides over the samples. It low-pass filters data, similar to the Gaussian filter. | Left Half Box | This filter produces a lag on the data, uses only samples back in time, and otherwise acts like a box filter. | Edge Detect | This filter detects “edges”, sharp changes in the input channels. It acts as a high pass filter. As the filter width is increased, more low frequencies are added. | Sharpen | This filter sharpens all high frequencies. It is the sum of the edge detect result and the original data. | De-spike | This filter removes “spikes” (samples more than `Spike Tolerance' above or below of the expected sample value). The filter width allows you to eliminate spikes that are several samples long. Wide filters will remove wide spikes (spikes of several samples) and small filters will only remove narrow spikes (one or two samples in length). |
|
Effect | The extent to which the filter affects the channel (0 - not at all, 1 - maximum effect). |
Filter Width | The amount of surrounding samples used in the calculation of the current sample. It is expressed in Units (in the Common page). |
Spike Tolerance | For the De-spike filter type, this is the amount that a sample can differ from its neighbors without being considered a spike. |
Number of Passes | The number of times the filter is applied to the channel. |
