A 560 Mbit/s FSK modulation/heterodyne detection free space optical link

Reviews the performance of heterodyne and homodyne coherent detection techniques and their advantages over a direct detection system. Theoretical analysis and factors affecting the design of a frequency shift keyed (FSK) modulation/heterodyne detection optical link using a nonsynchronous dual filter demodulation system suitable for intersatellite link (ISL) use is discussed. The design of the various subsystems including the optical transmitter, optical receiver, optical interfaces, IF amplifier, frequency discriminator and FSK data demodulator are described for an experimental system currently being constructed.<
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