Baseband Signals have zero imaginary component I was revising a few basics on communication systems and I stumbled upon this line that I thought was incorrectly articulated.
I thought that baseband signals were complex and passband signals were real.
If $x_z (t)$ is the baseband signal with in-phase component $x_I (t)$ and quadrature component $x_Q (t)$ such that $$x_z (t) = x_I (t) + j x_Q(t)$$ then passband signal is $$x_c (t) =\sqrt{2} Re(x_z (t)e^{2\pi f_c t})$$ which would imply that baseband signals may have non zero imaginary component and passband signals cannot have non-zero imaginary component.
But still the following statement from the book(Fundamentals of Communication System by Michael P.Fitz Chapter:Digital Communication Basics) seems to say it the other way around:

The only caveat that needs to be stated is that baseband data
communication will always have a zero imaginary component, while for
bandpass communication the imaginary component of the complex envelope
might be nonzero.

Is this statement incorrect or am I misconstruing it somehow?
You're right, but you've misread the sentence:
Baseband Data Communication means that there's no $f_c$.
For example, your USB cable to your keyboard, that's baseband communication. It can only carrier real-valued signals, so you only get to choose one dimension, not two, of signal freedom.
This is opposed to passband systems, where you can modulate the baseband signal up to a carrier frequency, which means your negative (relative to $f_c$) frequency spectrum doesn't have to have the same content as the positive.