  Oscillations of local density of states generated by a single scalar impurity
potential are calculated for one-dimensional systems with dynamically generated
charge or spin gap. At zero temperature the oscillations develop at finite wave
vector ($\pi$ for the Mott insulator and $2k_F$ for ICDW/SC) and at frequencies
larger than the soliton spectral gap $m$. Their amplitude has a broad maximum
at $\omega \approx 3m$, where $m$ is the gap magnitude.
