Abstract— In this paper, a simple modulation code called symbol insertion for band-limited single-carrier systems is proposed. This code can reduce the peak-to-average power ratio (PAR) with an inherent forward error correction (FEC) capability. The idea of the proposed code is as follows; since the PAR is largely proportional to the phase shifts of consecutive discrete symbols, we eliminate large phase shifts by inserting redundant symbols every after information symbols. Furthermore, exploiting the fact that the insertion process has a trellis structure, we employ the symbol insertion as a component code of concatenated codes. An 8-PSK example demonstrates not only that the PAR reduction performance is superior to conventional PAR reduction schemes, but also that the coding gain is as large as those of conventional capacity-approaching turbo and LDPC codes. Another advantage of the proposed system is simplicity of both coding and decoding processes.