We study the quality of the terrestrial digital video broadcasting (DVB-T) transmission over the cable TV network. Generally, when terrestrial digital TV signals are distributed in the cable TV, a conversion is needed in the head-end, from DVB-T (OFDM) to DVB-C (single carrier). In order to avoid this costly conversion and to transmit DVB-T signal directly in the existent cable channel, many requirements have to be satisfied. It is known that phase noise represents the main limitation for OFDM based systems. In this contribution we demonstrate the sensitivity of the OFDM system for the phase noise effects by using a dynamic model for CATV channel. Then, we conclude by giving the specifications that a converter in the CATV network should have to still allow the functionality of the DVB-T system.