Power spectral density shaping can be used in an XDSL system in order to adjust power spectral density properties of signals transmitted by an XDSL modem. The XDSL modem may include a power spectral density shaping filter, which can be adjusted to change the power spectral density properties of outputted signals. A processor may also perform power spectral density shaping of signals transmitted by the XDSL modem. The power spectral density shaping may be used to increase a downstream transmission rate.