How do I ensure that the filter edges are exactly at the points where I want them?

To ensure exact setting of the filter edges, it is required to create a change of the port at the frequency where the edge is supposed to be.  For example,  when using the .wsp filter definition this can be implemented as shown in the following snippet for a .wsp file:

193.000   60            0              0
193.001    60            0              0
193.002   60            0              0

193.009   60            0              0
194.000   0              0              1
194.001    0              0              1

194.098   0              0              1
194.099   0              0              1
194.100   60            0              0

194.109   60            0              0
194.110    60            0              0
194.111     60            0              0

This creates a bandpass filter where the edges are exactly at the frequency points as defined by the wsp file. The important detail is that a port change has been entered in the fourth column. The signal is guided to port 1 only in the spectral window which is desired.

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