Voltage mode ASK/BPSK modulator, its extended applications in precision rectifier and data communication using DXCCII

摘要

In this paper, two new modulator circuits are presented to realize two types of digital modulations, namely amplitude shift keying (ASK) and Binary phase shift keying (BPSK). The modulator circuits use one dual-X second-generation current conveyor (DXCCII), three MOS transistors, and one or two resistors. Since in data communication, there is a need for a demodulator and a modulator, a basic demodulator as an application of ASK modulator is presented using a rectifier, envelope detector, and comparator. Moreover, in an integrated circuit (IC), the modularity of sub-circuit is preferred, especially for the ease of fabrication. In maintaining the modularity, an attempt is made to design a precision rectifier, needed for demodulator, as an extension of the proposed modulator with little modifications. The proposed modulators possess the following important features: use all grounded passive components, ASK and BPSK obtain simultaneously, no need for matching passive components, circuits are fully cascadable and easily extendable to a precision rectifier. A non-ideal analysis is carried out. The proposed circuits are verified by PSPICE simulation with a supply voltage of +/- 0.9 V in 0.13 mu m CMOS TSMC technology. Simulation results corroborate the theoretical proposition. Furthermore, the proposed ASK and BPSK modulator circuit is experimentally verified.