Same command. Different response.

Change gain and delay to see two models respond differently to the same repeating command.

Nominal and comparison responses across two cycles Solid blue is the nominal model. Dashed orange is the adjustable comparison. Their difference is summarized below. Normalized response +1.40−1.400.50 s1.00 s
Added phase lag from delay28.8°
RMS difference · normalized units0.336

Both models have a 25 ms first-order time constant. Command amplitude = 1. Steady-state response; startup transients are excluded.

Delay adds phase lag = 360 × frequency × delay in seconds. Faster commands add more lag for the same delay. RMS compares amplitudes and phase over complete cycles; it need not rise monotonically as phase wraps around.