VHF Data Modem/Baseband Data Signal Converter.

Abstract : A full duplex data modem, used for transmitting digital data over tactical VHF FM radios, has been designed and built. The modem has two operating modes. In the quasi-analog mode it can transmit at 75, 150, 300, 600, 1200, 2400, and 4800 bps, using binary FSK, MSK, and four-level FSK. In the X-mode it can transmit at 300, 600, 1200, 2400, 4800, 9600, and 16000 bps, using Manchester, conditioned, diphase, pair-selected ternary, delay modulation, bipolar, and twinned binary codes. This report contains the theory of operation, implementation, and test data on two units. (Author)