Patent ReferencesDigital filter bank Automatic frequency control system or an SSB receiver Radio transceiver having an adaptive reference oscillator Information communication system FDMA communications channel synchronizer Wide bandwidth device for demodulating frequency division multiplexed signals Time-varying trellis-coded modulation formats which are robust in channels with phase variations Rapid phase correcting carrier recovery circuit Coded modulation system using interleaving for decision-feedback equalization Trellis coded multilevel DPSK system with doppler correction for mobile satellite channels InventorsAssigneeApplicationNo. 598396 filed on 10/18/1990US Classes:370/312, Message addressed to multiple destinations370/314, Using time division multiplexing370/436, Combined time and frequency assignment375/344, Automatic frequency control381/2, Broadcast or multiplex stereo455/65, Anti-multipath455/257, Automatic455/260, Phase lock loop or frequency synthesizer714/786Forward error correction by tree code (e.g., convolutional)ExaminersPrimary: Olms, Douglas W.Assistant: Ton, Dang Attorney, Agent or FirmInternational ClassH04J 004/00AbstractA digital audio broadcasting system that is capable of providing a large number of high quality stereophonic channels to mobile receivers in an environment with severe multipath delay and fading. Optimum combination of frequency and time diversity to guarantee robust performance in the mobile channel, with its multipath delay and frequency-selective fading effects. The system is based upon a dynamic single channel per carrier assignment of each stereo channel to many carriers. Intersymbol interference degradations caused by multipath delay are mitigated via an adaptive equalizer in the receiver. This dynamic single channel per carrier system preserves the simplicity inherent in the single channel per carrier assignment while it incorporates the ability to address frequency-selective fading by providing substantial frequency diversity. The frequency diversity is achieved via a slow frequency hop implementation in which the assignment of a number of stereo channels to an equal number of carrier frequencies is changed periodically. The system offers the simplicity of single channel per carrier assignment of stereo channels while it achieves the powerful performance benefits of frequency diversity and adaptive equalization for the mobile channel.Field of SearchWobbling of carrierPlural carrier frequencies Time segment interchange Anti-multipath Frequency or phase modulation With frequency multiplication or division Automatic Utilizing particular local oscillator control Reference oscillator or source Phase lock loop or frequency synthesizer Broadcast or multiplex stereo | |