| 摘要 |
In a system for simulcasting a digitally modulated signal and an analog FM signal over the same FM frequency band, the composite signal is received and applied to a conventional FM receiver, and a digital receiver in accordance with the invention. An extended Kalman filter is employed in the digital receiver to estimate the analog FM signal based on a version of the recovered FM signal from the FM receiver, and a discrete version of the composite signal whose spectrum has been translated and is at an intermediate carrier frequency. The estimated FM signal, which is in a discrete form, is subtracted from the discrete version of the composite signal. The resulting signal, which is an estimated version of the digitally modulated signal, is demodulated to recover the digital data as transmitted. |
