Adaptive equalization and phase tracking for simultaneous analog/digital data transmission

The general problem of equalization for data transmission where one of the two data sources produces continuous amplitude data samples is studied. There are various ways to configure a modem for such a transmission scheme, and we describe how a standard quadrature amplitude modulation structure can be modified to operate in this mode. This solution can be specialized to include various linear modulation schemes, such as single sideband and vestigial sideband. Theoretical analysis shows that adaptive equalization and adaptive phase tracking can be achieved with similar quality as in the familiar digital-only modem. We provide extensive computer simulation results which confirm the validity of our theory.