@ben.wes Thanks again for testing, really helpful!
Yes, it's true, that I didn't care about consecutive non-zero samples. For now I'm not sure what's more important: to comply to this constraint or to behave properly above nyquist.
The problems with frequencies above nyquist, that you found, probably have to do with the representation of small floating point numbers. I should have used [expr~ int($v1)] to get real zero values. Can't fix it right now, but I'll try tomorrow ...