Abstract: A system and method for amplitude modulating a carrier signal with an audio or other information input signal relies on multivibrators and comparators initiating a logic controlled processing technique for providing two sinusoids, each a fundamental frequency waveform, the two having a mutual phase relationship defined by intermediate processing steps such that they differ in phase from 0 to 180 electrical degrees. The comparators output first resultant pulses when the carrier signal is greater than the amplitude of the audio or other information input signal. The first resultant pulses are input to a logic processing network to trigger multivibrators which output overlapping 180.degree. wide pulses, respective phase shifted resultant signal waveforms being formed from the respective comparator outputs.

Abstract: A pair of square waves of a carrier frequency are applied respectively to a pair of amplifier circuits having a common output circuit. The output circuit is connected so that the energy therein is dependent upon the relative phases of the square waves. A further circuit is provided for varying the relative phases of the two square waves, so that the output from the output circuit is in the form of amplitude modulated oscillations.

Abstract: An output transformer, especially useful to couple a balanced output stage to an unbalanced load, employs first and second primary winding halves, which have their "center taps" physically offset, and wherein the windings are wound coextensively for some but not all of their length. The secondary winding is wound coextensively with one or the other of the two primary halves, thereby improving the coupling and reducing leakage inductance and also reducing the interlayer volt amperes and thus reducing interlayer capacitance.