Patent ID: 7706468
Filing Date: 2010-04-27
Classification: H04H,H04L

Abstract:
1. A transmitter for broadcasting an AM compatible digital audio broadcasting signal, the transmitter comprising: 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; 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, wherein 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 the analog modulated signal is delayed with respect to the plurality of digitally modulated subcarrier signals, 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 and a first group of the plurality of digitally modulated subcarrier signals are delayed with respect to a second group of the plurality of digitally modulated subcarrier signals; and an antenna for broadcasting the analog modulated signal and the plurality of digitally modulated subcarrier signals.