This paper investigates the high-frequency responses of HVDC-MMC links, emphasizing the importance of harmonic and resonance phenomena on the AC grid. Utilizing EMT-type simulations, the study analyzes various MMC station and AC network parameters to assess their effects on system stability and performance. The findings demonstrate that certain configurations, such as the number of MMC levels and the setups of control systems, significantly influence harmonic emissions and the corresponding frequency response.