In a wireless communication system, a method and apparatus improves a data transmission rate of baseband data via a wireless transceiver adapted for voice transmission. A modem receives baseband data for distribution to a wireless transceiver. The modem complementary pre-conditions frequency amplitudes that are subsequently augmented or pre-emphasized by the wireless transceiver. The modem then modulates the pre-conditioned baseband data for transmission by the wireless transceiver. Modulation may be performed using a single-carrier, multiple-carrier or a carrierless technique. The wireless transceiver pre-emphasizes the modulated pre-conditioned baseband data for presenting a consistent or flat amplitude spectrum to the RF transmitter.