Abstract: The problems of high cost, high loss and incomplete distortion compensation are resolved in a distortion generating circuit which employs a nonlinear phase modulator (70, FIG. 7) and a linear phase shifter (71) as a means of generating selected distortion signal components. The circuit includes an output coupler (30) and an output coupler (31) interconnected by means of a pair of wavepaths (32, 33). The nonlinear phase modulator (70), which includes a nonlinear reactive element (37), is disposed in one of the wavepaths (32). The linear phase shifter (71) is included in the other wavepath (33). By the appropriate adjustment of the linear phase shift in wavepath (33) the entire gamut of distortion characteristics can be compensated. Distortion generating circuits of the type disclosed can be employed as either predistorters or as postdistorters to compensate for the nonlinearities in electromagnetic signal devices, such as amplifiers.