Serial MSK modem for the Advanced Communications Satellite Program

The design and test results of the 550-Mb/s, 110-Mb/s, and 27.5-Mb/s modems for the Advanced Communication Satellite Program are described. The TDMA/FDMA satellite environmental constraints have resulted in several unique features which include total acquisition times of 100 bit times and modem degradation of less than 1.5 dB at 10 to the -6th Pe. Key to the serial implementation of MSK is the resulting hardware simplicity and degradation insensitivity relative to conventionally implemented MSK and QPSK modems. The 110/27.5-Mb/s modems use an integrated circuit specifically developed for the program to perform the key carrier and clock-loop functions.