COMPACT LSI- AND MIC-IMPLEMENTED BURST MODEM FOR LOW EB/NO OPERATION.

The authors propose a highly reliable and compact low E//b/N//0 burst modem for TDMA satellite communication systems. To realize stable operation in low E//b/N//0 environments and reduce adjustment complexity or burst modems, two techniques are proposed: (1) a carrier recovery circuit using a reverse modulation scheme with precise digital Costas APC (automatic phase control) and (2) a phase-compensated carrier tank. By extracting and classifying basic functions of burst modems, eleven kinds of widely applicable modem ICs (three digital LSIs, four high-speed silicon MICs and four thick-film HICs) which are applicable to various clock rate and IF frequency burst/continuous modems have been developed. The advent of these modem ICs has made it possible to reduce the hardware size of burst modems to one half of a conventional one, consequently increase reliability significantly and contributes to reduce maintenance and adjustment works. The prototype LSI- and MIC-implemented burst modem shows superb performance even if in low E//b/N//0 environments and satisfactory performance.