An apparatus for generating a substantially constant DC reference voltage. The apparatus includes a reference voltage generator configured to generate a substantially constant direct current (DC) reference voltage based on a voltage on a data signal transmission line, wherein the voltage is based on a bandgap reference voltage. In one implementation, the data signal transmission line is a differential signal transmission line and the voltage is a common mode voltage. In another implementation, the data signal transmission line is an I-data signal transmission line and a Q-data signal transmission line, and the voltage is an average or weighted-average of the common mode voltages of the I- and Q-differential signals. In another implementation, the reference voltage is based on a single-ended (e.g., positive- and/or negative)-component or vice-versa of I- and Q-data signals, respectively.