Multi-Sample Error Protection Modulation Study.

Abstract : The results of this study indicate that analog information can be transmitted with a significant improvement in signal fidelity, measured in terms of output (received) signal-to-noise ratios, by optimizing the coding and modulation formats to give additional protection to those quantized bits which are critical to signal fidelity. The systems considered are similar to pulse code modulation (PCM) systems, but generally are superior to conventional PCM systems as well as analog frequency modulation and phase modulation systems. In fact, certain practical configurations which are directly applicable to the Defense Communication System are shown to yield improvements in output SNR's which are 15 dB greater than that possible for PCM and within a dB of that possible by the use of optimum codes which satisfy the channel capacity limit. (Author)