In this paper, using of rectangular-wave (binary and ternary) chirps as excitation signals for broadband impedance measurements (incl. bioimpedance monitoring) is discussed. In general, all kinds of chirp signals enable the measurement and object identification in wide frequency range during a short measurement cycle. The aim of this work was to analyze spectral properties and energy distribution of the rectangular-wave chirps as the alternative to the traditionally used sine-wave ones. It is shown that in addition to the simpler generation and processing, the energy efficiency of rectangular-wave chirps is sufficiently high, which is especially important for the miniaturized measurement devices.