All filters are built so that when lower orders are needed, unused elements are disabled, to not uselessly encumber the matrix solver. The price to pay for this is that any parameter influencing the placement or the number of elements (like the order), cannot be used with the
.step command (e.g.
.step param N 1 4 1 won't work).
Because of the above, if the filter is not used with its maximum order (whichever the filter), the error log will fill up with messages like "
Gh_242: all pins shorted together -- ignoring."; it's safe to ignore them.
If errors like
"Analysis Failed: Matrix is singular" show up, it may be because the calculated order is larger than it can handle. The error log can confirm this if it generates messages similar to
"WARNING: Node U1:17 is floating". For example, this particular error means that the required order for an Analog Active LP is either
34. The FIRs are polyphase but, even if the numbers will be different, the log will complain about the same floating nodes.
©Vlad, 2008 - 2015