Second-order IMD cancellation receiver for wideband coherent SCM systems

A novel receiver design for coherent subcarrier multiplexed (SCM) systems is demonstrated with a 20-channel digital video system in a multioctave configuration. System performance is enhanced by cancelling second-order intermodulation distortion and detecting both sidebands containing the microwave information. A multioctave 20-channel heterodyne SCM differential quadrature phase shift keying (DQPSK) experiment demonstrated the technique, achieving a receiver sensitivity of -40 dBm, which represents a 12 dB gain over the standard receiver design for this system configuration. >