We present the full phase and intensity characterization of ultrafast pulses via dispersion scans. The pulses are generated in an Yb-doped fiber oscillator, mode-locked by non-linear polarization evolution, operating at a central wavelength of 1030 nm. These output pulses are stretched in a 150 m long fiber to approximately 50 ps and recompressed in a grating-prism compressor. In order to realize different chirps on the pulses for the dispersion scans, the dispersion compensation by the grating-prism compressor is varied by changing the prism separation.