Four state phase shift modulator, in particular for amplitude modulation of two carriers in quadrature with a large number of states

Abstract From the Canadian patent

A modulator having a four output signal generator generating a signal with four phases shifted by 90°. A four carrier input phase selector is connected to the outputs, with four modulating signal inputs and four phase shifted carrier outputs. Each modulating signal input is connected to the control input of a switch between a carrier input and a phase shifted carrier output. The generator is comprised of a source of signals in opposite phase and two frequency dividers having two outputs of opposite phase. It also has two pairs of flip-flops whose outputs form the four outputs of the generator. The signal inputs of one pair of flip-flops are connected to the outputs of the first divider and …