Support Forums › Forums › FIR Designer M Support › step into phase plot › Reply To: step into phase plot
Hi Thomas,
The region around 150 Hz has fairly high phase slope at import and it looks like the tabs, prior to the Phase Adjust tab, have added additional phase slope; which looks to be from HP filtering. The result is a phase slope high enough that it’s marginal*, in the plotting, between showing a step between plot points (as in your screenshot) and wrap. Given that this freq region way out of band – it looks to be at approximately -60 dB relative to the passband – it’s safe to ignore.
* The plotting groups/averages the >16000 raw FFT data points into a smaller log frequency spaced set at approx. 1/96th oct spacing. Sometimes in this averaging, very high phase slope regions can go either way.
Best regards,
EA Support