Patent ID: 7050511

Claim:
An in-band adjacent-channel digital audio broadcasting system, comprising: a scrambling unit for scrambling a signal to be broadcasted, thereby generating a scrambled signal; an outer coding unit for performing a first encoding including a Reed-Solomon (RS) coding of the scrambled signal, thereby generating an outer encoded signal; an outer interleaving unit for performing a first interleaving of the outer encoded signal on a byte by byte basis, thereby generating an outer interleaved signal; an inner coding unit for performing a second encoding including a convolutional coding and a trellis coding of the outer interleaved signal, thereby generating an inner encoded signal; an inner interleaving unit for performing a second interleaving of the inner encoded signal, thereby generating an inner interleaved signal; a modulating unit for modulating the inner interleaved signal, thereby generating an orthogonal frequency division multiplexing (OFDM) symbols, the modulating unit including: a signal mapping unit for generating 8PSK or 16QAM data samples based on the inner interleaved signal; a frame adapting unit for constructing a transmission frame based on TPSs, pilot samples and data samples; and an IFFT unit for performing an inverse fast Fourier transform (IFFT) of the transmission frame to generate OFDM symbols; a guard interval inserting unit for inserting a guard interval between the OFDM symbols in order to eliminate an inter-symbol interference, thereby generating an OFDM frame; and an RF processing unit for performing a conversion of the OFDM frame into an analog radio frequency signal so that the OFDM signal can be transmitted in a specific frequency channel of an FM frequency band, and for amplifying and outputting the analog radio frequency signal, wherein the system concurrently supports both of coded-orthogonal frequency division multiplexing (COFDM) and Trellis COFDM (TCOFDM) transmission modes based on the same systematic parameters, and a conversion of the COFDM and the TCOFDM transmission modes is efficiently embodied by a change of an output data rate of an MPEG-2 multiplexer.