Vector Integrators

In this paper it is shown that it is impossible to realize a causal, linear, time-invariant two-port which integrates an arbitrary modulation on a suppressed carrier input while leaving the carrier unchanged. It is shown further that a realization of a four-port integrator is possible, provided the two inputs to the four-port have the same modulation but are on quadrature carriers. A specific realization of such an integrator, called a vector itegrator, is exhibited and its applications are discussed.