1. Product Modulator Since expression for DSB-SC is s(t)=x(t)coswct From this expression, we see that DSB-SC signal is basically the product of the modulating or baseband signal and the carrier signal. So, circuit to achieve the generation of DSB-SC is called a Product Modulator.
2. Modulation using nonlinear devices(Balanced Modulator) Balanced modulators are AM circuits that cancel or suppress the carrier but generate a DSB output signal that contains the upper and lower sideband frequencies. Non linear resistances are used to produce AM. If two nonlinear devices are connected in balanced mode so as to suppress the carriers of each other, then only sidebands are left.