A transmitter for broadcasting an AM compatible digital audio broadcasting signal includes an analog modulator for producing an analog modulated carrier signal centrally positioned in a radio channel, wherein the analog modulated carrier signal is modulated by an analog signal, and a digital modulator for producing a plurality of digitally modulated subcarrier signals in the radio channel, wherein the digitally modulated subcarrier signals are modulated using complementary pattern-mapped trellis code modulation including a code mapped to overlapping partitions. In a first operating mode the analog modulated carrier signal and the plurality of digitally modulated subcarrier signals are in a 20 kHz channel and in a second operating mode the analog modulated carrier signal and the plurality of digitally modulated subcarrier signals are in a 30 kHz channel.