LETTER Design andAnal of an Automatic Gain Control Scheme for HighSpeedSatel Communication.pdf

IEICE TRANS. COMMUN., VOL.E83–B, NO.1 JANUARY 2000 99 LETTER Design and Analysis of an Automatic Gain Control Scheme for High-Speed Satellite Communications † † Myung Sup KIM and Jin Suk SEONG , Nonmembers SUMMARY We propose a coherent automatic gain control modem for high-speed satellite communications. The (AGC) scheme with low complexity for high-speed satellite com- carrier phase required in the proposed scheme could be munications. A mathematical model for the gain detector and a obtained by the algorithms suggested by Kim [2] and stochastic difference equation are established to investigate the characteristics of the scheme. Based on the random process the- Matsumoto [3]. We analyze the performance of the pro- ory with the equation, we analyze the acquisition and tracking posed scheme by using a stochastic difference equation performance of the AGC loop. It has been verified that the re- derived from the operation of an integrator. The results sults by the analytical method agree with the simulation results give us an insight for the operation and performance obtained in the presence of small amount of phase offsets in the of the proposed scheme, unlike the complicated results carrier recovery circuits for the QPSK system. Though the ana- lytical results deviate from the simulation results slightly in the obtained by Popken [4], Ohlson [5] and McGeehan [6]. presence of maximum phase offset, th