A transparent repeater for digital communication signals

A method is presented for retransmitting a digital communication signal over channels with different signal-to-noise ratios (SNRs), without complete demodulation and remodulation (Demod/Remod). The method, which we call signal code modulation (SCM), converts samples of the incoming signal into digital and analog symbols whose characteristics are designed to match the channel. The SCM method trades bandwidth for SNR in the classical manner and achieves a performance close to that of conventional Demod/Remod methods. However, it does so by performing relatively simple operations on the sampled input signal and does not require detailed knowledge of its fine structure (framing, coding, etc.)