PR 22656 is a shot at resolving the oldest open issue in the signal module, namely #1507. It provides the new functions sawtooth_rfft and square_rfft, which return the one-sided discrete Fourier transform of a sawtooth and a square waveform. This allows to efficiently create band-limited signals by utilizing the irfft function.
The following image (from the example of the square_rfft docs) illustrates this: The over- and undershoots at the edges of the square wave are due to the (Nyquist) bandwidth of 50 Hz.
Please head over to PR 22656 and join the discussion there.