Method and system for receiving digital broadcasting signals in frequency modulation (FM) broadcast bands

Abstract

The invention relates to a method and a system for receiving digital broadcasting signals in frequency modulation (FM) broadcast bands. The method comprises the following steps of: receiving digital / analog (D / A) mixed signals x (t); preliminarily separating to acquire preliminarily recovered analog FM signals x0FM (t) and digital FM signals d0 (t); performing first level pilot frequency-based iterative separation on the signals to acquire digital and analog FM signals after the first level iterative separation; and performing second level iterative separation by means of pilot frequency and internal codes, wherein the digital FM signals after the iterative separation acquire digital audio signals and data signals through channel decoding, and the analog FM signals acquire analog audio signals through demodulation and D / A conversion. A digital FM signal demodulation decoder of the system comprises a preliminary FM separator, an iterative FM separator, and a synchronization recovery and channel equalizer and a decoding module, and the iterative offset separation of the analog master FM from digital signals is realized. According to the method and the system, the mixed D / A signals overlapped by the same channel are separated, the mutual interference of the signals is eliminated, and the FM band digital broadcasting system can be realized.

Description

(1) Technical field [0001] The invention belongs to the technical field of digital audio broadcasting, in particular to a method and a receiving system for receiving digital broadcasting signals in FM broadcasting band. (2) Background technology [0002] AM (Amplitude Modulation, AM) broadcasting began in 1920, and FM (Frequency Modulation, FM) broadcasting began in 1940. In my country, from the 1950s to the 1960s, medium and short-wave broadcasting developed rapidly. In the 1970s, FM broadcasting rose rapidly, and the sound quality of broadcasting was significantly improved. FM broadcasting has been widely used. Although with the rapid development of TV, Internet, and mobile communication network, traditional audio broadcasting has once become a secondary important media method, and its development speed is far behind other major communication methods, but audio broadcasting has its specific application environment and Demand, is still a very important form of media, and w...

AI Technical Summary

Problems solved by technology

[0020] Therefore, in the real TIBOC digital-analog audio broadcasting system with the same frequency and the same band, the spectrum of the analog main FM signal and the digital modulation signal completely overlap. Using the traditional FM separation technology, the demodulated analog FM signal will become a part of the OFDM signal, and The residual noise power from the analog FM signal will be much greater than the power of the OFDM signal, so that the recovered digital modulation signal cannot meet the requirements of a certain signal-to-noise ratio, affecting the receiving quality of the digital modulation signal

At the same time, the interference of the digital modulation signal to the analog main frequency modulation signal makes the analog main frequency modulation signal unable to recover accurately

This key technical problem makes it difficult to realize a digital-analog audio broadcasting system with completely overlapping digital-analog spectrum

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