Research Article Realization of DVCCTA Based Versatile Modulator Neeta Pandey, 1 Rajeshwari Pandey, 1 Aseem Sayal, 2 and Manan Tripathi 2 1 Department of Electronics & Communication Engineering, Delhi Technological University, Delhi 110042, India 2 Department of Electrical Engineering, Delhi Technological University, Delhi 110042, India Correspondence should be addressed to Neeta Pandey; n66pandey@redifmail.com Received 31 May 2014; Accepted 7 October 2014; Published 27 October 2014 Academic Editor: Stephan Gif Copyright © 2014 Neeta Pandey et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A Diferential Voltage Current Conveyor Transconductance Amplifer (DVCCTA) based versatile modulator is proposed which can work as an amplitude modulator, frequency modulator, delta modulator, and sigma delta modulator. Te modulator operational scheme uses pulse generator as a core and its output is used as carrier signal. A DVCCTA based pulse generator is proposed frst and subsequently confgured as diferent modulators. Compact realization is the key feature of the proposed circuit as it uses two DVCCTA; a grounded resistor and a grounded capacitor hence are appropriate for IC realization. Te functionality of the proposed circuit is verifed through SPICE simulations using TSMC 0.25 m CMOS process model parameters. Te performance parameters such as power dissipation and noise for various modulator schemes are also obtained. 1. Introduction Modulation is a process of modifying some characteristic of a carrier signal according to the instantaneous value of modulating signal and is a fundamental requirement of any communication system. Analog and digital modulations are two representative classes of modulation techniques. Amplitude and frequency modulation fall under analog modulation schemes wherein amplitude and frequency of the carrier signal, respectively, are varied according to the instantaneous value of the modulating signal while keeping other parameters constant. Delta and sigma delta modulation belong to digital modulation and are widely used in digital communication and digital signal processing and analog to digital converters. Mobile communication systems and portable electronic equipment demand low-power circuitry to enable longer battery operation. Te current-mode (CM) processing has emerged as a promising solution for such circuits as CM circuits are designed for lower voltage swings. Exploiting this virtue of CM processing the researchers have reported a large number of modulator circuits using diferent CM active building blocks (ABB) such as current conveyor II (CCII) [1], operational transconductance amplifer (OTA) [2–4], cur- rent controlled current diference transconductance amplifer (CCCDTA) [5], multiple output current controlled current diference transconductance amplifer (MOCCCDTA) [6], and operational transresistance amplifer (OTRA) [7]. Te pulse width of the carrier signal is modulated in accordance with input modulating signal in circuits proposed in [1–7]. Sigma delta modulators are the other class of modulators available in literature [4, 8–15]. Tese modulators can be classifed as designs based on (i) switched capacitor technique [8–11], (ii) switched current technique [12], (iii) Loop flter and quantizer method [13–15], and (iv) ABB [4]. A detailed comparison of these structures is given in Table 1. It is evident from Table 1 that a large number of modulator circuits are available in literature but only the modulator structure of [4] can provide amplitude, frequency, delta, and sigma delta modulated outputs. In this paper, a DVCCTA based versatile modulator is presented which employs two ABBs and two grounded passive elements only as against the three ABBs and three passive elements used in [4]. Te paper is organized as follows. Section 2 describes the port relation of DVCCTA and its CMOS based imple- mentation. Operational scheme of the proposed modulator Hindawi Publishing Corporation Active and Passive Electronic Components Volume 2014, Article ID 342785, 9 pages http://dx.doi.org/10.1155/2014/342785