Methods, apparatus, systems and articles of manufacture are disclosed to transmit signals in isolated gate drivers. An example apparatus includes a first encoder including: an edge detector coupled to a first sensor; a first clock counter coupled to the edge detector; a first signal selector coupled to the first clock counter; and a first multiplexer coupled to a signal generator, the first clock counter, and the first signal selector; and a second encoder including: a level detector coupled to a second sensor; a second clock counter coupled to the level detector; a second signal selector coupled to the level detector and the second clock counter; and a second multiplexer coupled to the first multiplexer, a reference voltage, the second signal selector, and a modulator.