1. The documentation (ADC-212) is cryptic as far as what piece of data the spectrum performs an FFT on. Can I be sure that if I collect temporal data in a display window that the spectrum is actually calculated from that same data, not some other piece of the data stream? This conclusion seems inconsistent with the fact the you can vary the timebase at will regardless of the spectrum settings.
2. How do I set the vertical scale of the FFT to fixed limits (e.g. from -20 dB to -100 dB) so it doesn't fly around all over when the spectrum changes rapidly?