A channel sounder based on the cross-correlation properties of pseudo-noise (PN) random sequences, known as swept time delayed cross-correlation (STDCC) channel sounder, is presented. This sounder enables the characterisation of doubly selective channels, providing both amplitude and extit{Doppler} spectra information. It performs real time measurements of specific radio channels with a high resolution of 2 ns for adjacent multipath component (MPC), and a current maximum extit{Doppler} spread of $pm$100 Hz, but that can go beyond $pm$1 kHz, if some components are upgraded. The amplitude measurements given by the sounder, presented as power delay profiles (PDP), have a dynamic range of about 35 to 40 dB.

This paper provides detailed information on the most relevant components used to develop the sounder, and presents some of the calibration measurements performed on the bench, as well as specific radio frequency (RF) measurements at 18.7 and 60 GHz in a controlled environment.

Finally, improvements that are feasible to be implemented in the near future are proposed.