Research Article  Open Access
K. L. Pushkar, D. R. Bhaskar, Dinesh Prasad, "SingleResistanceControlled Sinusoidal Oscillator Using Single VDDIBA", Active and Passive Electronic Components, vol. 2013, Article ID 971936, 5 pages, 2013. https://doi.org/10.1155/2013/971936
SingleResistanceControlled Sinusoidal Oscillator Using Single VDDIBA
Abstract
This paper presents a new singleresistancecontrolled sinusoidal oscillator (SRCO). The proposed oscillator employs only one voltage differencing differential input buffered amplifier (VDDIBA), two resistors, and two grounded capacitors. The proposed configuration offers the following advantageous features: (i) independent control of condition of oscillation and frequency of oscillation, (ii) low active and passive sensitivities, and (iii) a very good frequency stability. The validity of the proposed SRCO has been established by SPICE simulations using 0.35 μm MIETEC technology.
1. Introduction
Realisation of oscillators and active filters has become important research area in analog circuit design. Recently, various modern active building blocks have been introduced in [1], and VDDIBA is one of them which is emerging as a very flexible and versatile building block for analog signal processing and has been used earlier for realizing a number of functions. Singleresistancecontrolled sinusoidal oscillators (SRCOs) play an important role in control systems, signal processing, communication, and instrumentation and measurement systems [2–4]. SRCOs employing different active building blocks have attracted considerable attention of the researchers due to their several advantages over traditional opampbased SRCOs; see [5–15] and the references cited therein. The applications, advantages, and usefulness of VDDIBA have now been recognised in the realisation of firstorder allpass filter, in simulation of inductors and in the realisation of sinusoidal oscillator [16–18]. However, to the best of the knowledge and belief of the authors, none of the SRCOs using single VDDIBA has yet been presented in the literature so far. Therefore, the purpose of this paper is to present a new SRCO using a single VDDIBA along with a bare minimum number of four passive components. The proposed configuration offers (i) independent control of condition of oscillation and frequency of oscillation, (ii) low active and passive sensitivities, and (iii) a very good frequency stability. The workability of the proposed SRCO has been established by SPICE simulations using 0.35 μm MIETEC technology.
2. New Oscillator Configuration
The schematic symbol and behavioral model of the VDDIBA are shown in Figures 1(a) and 1(b), respectively. The model includes two controlled sources: the current source controlled by differential voltage , with the transconductance , and the voltage source controlled by differential voltage , with the unity voltage gain. The VDDIBA can be described by the following set of equations: A routine circuit analysis of Figure 2 yields the following characteristic equation: Thus, the condition of oscillation (CO) and frequency of oscillation (FO) are given by Therefore, it is seen that FO is independently controllable by resistor and CO is controlled by .
(a)
(b)
3. Frequency Stability Analysis
Frequency stability may be considered to be an important figure of merit of an oscillator. The frequency stability factor is defined as , where is the normalized frequency, and represents the phase function of the open loop transfer function of the oscillator circuit, with , , , and ; for the proposed SRCO is found to be Thus, for larger values of , the oscillator enjoys a very good frequency stability.
4. Nonideal Analysis and Sensitivity Performance
Let and denote the parasitic resistance and parasitic capacitance of the terminal of the VDDIBA. Taking the nonidealities into account, namely, the voltage of terminal , where and denote the voltage tracking errors of terminal and terminal of the VDDIBA, respectively, then the expressions for CO and FO become The lefthand side of (3) with the component values shown in Section 4 turns out to be −0.812 which is in accordance with (3) (<0). On the other hand, when lefthand side of (6) is calculated using the components and parasitic values in Section 4, it turns out to be −0.7992. It is therefore seen that both values are quite close from these numerical examples; it can be inferred that by considering , and , , (6) becomes which shows that (6) is almost the same as (3).
Its active and passive sensitivities can be found as In the ideal case, the various sensitivities of FO with respect to , , , and are found to be Considering the typical values of various parasitic, for example, pF, kΩ, and along with nF, kΩ, and kΩ, the various sensitivities are found to be , , , , , , , and which are all low.
5. Simulation Results
To confirm theoretical analysis, the proposed SRCO was simulated using CMOS VDDIBA (as shown in Figure 3). The passive elements were selected as nF, KΩ, and KΩ. The transconductance of VDDIBA was controlled by bias voltage . PSPICEgenerated output waveforms indicating transient and steady state responses are shown in Figures 4(a) and 4(b), respectively. These results, thus, confirm the validity of the proposed configuration. Figure 5 shows the output spectrum, where the total harmonic distortion (THD) is found to be 2.77%. Figure 6 shows the variation of frequency with resistance . A comparison with other previously known SRCOs using different active building blocks has been given in Table 2.
(a)
(b)
The CMOS VDDIBA is implemented using 0.35 μm MIETEC real transistor model which is listed in Box 1.

Aspect ratios of transistors used in Figure 3 are given in Table 1.


6. Conclusions
A new application of a recently introduced VDDIBA in the realisation of SRCO has been proposed. The proposed configuration employs a minimum possible number of passive elements (namely, two resistors and two grounded capacitors) and yet offers independent control of FO through the resistor and CO through the transconductance (hence, the circuit enjoys the electronic control of CO), low active and passive sensitivities, and a very good frequency stability. This paper thus added a new application circuit to the existing repertoire of VDDIBAbased application circuits.
References
 D. Biolek, R. Senani, V. Biolkova, and Z. Kolka, “Active elements for analog signal processing: classification, review, and new proposals,” Radioengineering, vol. 17, no. 4, pp. 15–32, 2008. View at: Google Scholar
 R. Senani, “New types of sine wave oscillators,” IEEE Transactions on Instrumentation and Measurement, vol. 34, no. 3, pp. 461–463, 1985. View at: Google Scholar
 R. Senani and D. R. Bhaskar, “Single opamp sinusoidal oscillators suitable for generation of very low frequencies,” IEEE Transactions on Instrumentation and Measurement, vol. 40, no. 4, pp. 777–779, 1991. View at: Publisher Site  Google Scholar
 D. R. Bhaskar and R. Senani, “New CFOAbased singleelementcontrolled sinusoidal oscillators,” IEEE Transactions on Instrumentation and Measurement, vol. 55, no. 6, pp. 2014–2021, 2006. View at: Publisher Site  Google Scholar
 V. K. Singh, R. K. Sharma, A. K. Singh, D. R. Bhaskar, and R. Senani, “Two new canonic singleCFOA oscillators with single resistor controls,” IEEE Transactions on Circuits and Systems II, vol. 52, no. 12, pp. 860–864, 2005. View at: Publisher Site  Google Scholar
 S. Celma, P. A. Martinez, and A. Carlosena, “Minimal realisation for single resistor controlled sinusoidal oscillator using single CCII,” Electronics Letters, vol. 28, no. 5, pp. 443–444, 1992. View at: Google Scholar
 D. R. Bhaskar and R. Senani, “New currentconveyorbased singleresistancecontrolled/voltagecontrolled oscillator employing grounded capacitors,” Electronics Letters, vol. 29, no. 7, pp. 612–614, 1993. View at: Google Scholar
 C. T. Lee and H. Y. Wang, “Minimum realisation for FTFNbased SRCO,” Electronics Letters, vol. 37, no. 20, pp. 1207–1208, 2001. View at: Publisher Site  Google Scholar
 D. R. Bhaskar, “Groundedcapacitor SRCO using only one PFTFN,” Electronics Letters, vol. 38, no. 20, pp. 1156–1157, 2002. View at: Publisher Site  Google Scholar
 S. S. Gupta and R. Senani, “Groundedcapacitor currentmode SRCO: novel application of DVCCC,” Electronics Letters, vol. 36, no. 3, pp. 195–196, 2000. View at: Publisher Site  Google Scholar
 V. Aggarwal, S. Kilinç, and U. Çam, “Minimum component SRCO and VFO using a single DVCCC,” Analog Integrated Circuits and Signal Processing, vol. 49, no. 2, pp. 181–185, 2006. View at: Publisher Site  Google Scholar
 S. Özcan, A. Toker, C. Acar, H. Kuntman, and O. Çiçekoģlu, “Single resistancecontrolled sinusoidal oscillators employing current differencing buffered amplifier,” Microelectronics Journal, vol. 31, no. 3, pp. 169–174, 2000. View at: Publisher Site  Google Scholar
 U. Çam, “A novel singleresistancecontrolled sinusoidal oscillator employing single operational transresistance amplifier,” Analog Integrated Circuits and Signal Processing, vol. 32, no. 2, pp. 183–186, 2002. View at: Publisher Site  Google Scholar
 D. Prasad, D. R. Bhaskar, and A. K. Singh, “Realisation of singleresistancecontrolled sinusoidal oscillator: a new application of the CDTA,” WSEAS Transactions on Electronics, vol. 5, no. 6, pp. 257–259, 2008. View at: Google Scholar
 D. Biolek, A. U. Keskin, and V. Biolkova, “Grounded capacitor current mode single resistancecontrolled oscillator using single modified current differencing transconductance amplifier,” IET Circuits, Devices and Systems, vol. 4, no. 6, pp. 496–502, 2010. View at: Publisher Site  Google Scholar
 D. Biolek and V. Biolkova, “Firstorder voltagemode allpass filter employing one active element and one grounded capacitor,” Analog Integrated Circuits and Signal Processing, vol. 65, no. 1, pp. 123–129, 2010. View at: Publisher Site  Google Scholar
 D. Prasad, D. R. Bhaskar, and K. L. Pushkar, “Realization of new electronically controllable grounded and floating simulated inductance circuits using voltage differencing differential input buffered amplifiers,” Active and Passive Electronic Components, vol. 2011, Article ID 101432, 8 pages, 2011. View at: Publisher Site  Google Scholar
 D. Prasad, D. R. Bhaskar, and K. L. Pushkar, “Electronically controllable sinusoidal oscillator employing CMOS VDDIBAs,” ISRN Electronics, vol. 2013, Article ID 823630, 6 pages, 2013. View at: Publisher Site  Google Scholar
Copyright
Copyright © 2013 K. L. Pushkar et al. This 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.