A novel versatile modulator circuit

In this paper, a novel versatile modulator that can function either as delta modulator, sigma-delta modulator, amplitude modulator and frequency modulator is proposed. The principle of the proposed scheme is based on Schmitt-trigger circuit and composed of a few components: three OTAs, one capacitor and two resistors. The advantage of this circuit is that the clock (carrier) signal employed for modulation is inherent in the circuit. The modulating signal is therefore an external input requirement. Based on the compactness of the circuit, it is suitable for IC realization. The computer simulation demonstrates the results which agree well with the theoretical analysis.