System Identification Toolbox™

realdata - Determine whether iddata is based on real-valued signals

Syntax

realdata(data)

Description

realdata returns 1 if

• data contains only real-valued signals.

• data contains frequency-domain signals, obtained by Fourier transformation of real-valued signals.

Otherwise realdata returns 0.

Notice the difference with isreal:

load iddata1
isreal(z1); % returns 1
zf = fft(z1);
isreal(zf) % returns 0
realdata(zf) % returns 1
zf = complex(zf) % adds negative frequencies to zf
realdata(zf) % still returns 1

rbj

resample