Circuits and Systems, 2013, 4, 264-268
http://dx.doi.org/10.4236/cs.2013.43035 Published Online July 2013 (http://www.scirp.org/journal/cs)
Fully Uncoupled Electronically Controllable Sinusoidal
Oscillator Employing VD-DIBAs
Data Ram Bhaskar1*, Dinesh Prasad1, Kanhaiya Lal Pushkar2
1Department of Electronics and Communication Engineering, Faculty of Engineering and Technology,
Jamia Millia Islamia, New Delhi, India
2Department of Electronics and Communication Engineering, Maharaja Agrasen Institute of Technology, Rohini,
New Delhi, India
Email: *dbhaskar@jmi.ac.in, dprasad@jmi.ac.in, klpushkar@rediffmail.com
Received March 21, 2013; revised April 22, 2013; accepted April 30, 2013
Copyright © 2013 Data Ram Bhaskar et al. This is an open access article distributed under the Creative Commons Attribution Li-
cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Recently, voltage differencing-differential input buffered amplifiers (VD-DIBA)-based electronically controllable si-
nusoidal oscillator has been presented that it does not have the capability of complete independence of frequency of
oscillation (FO) and condition of oscillation (CO) as well as electronic control of both CO and FO. In this article, a new
fully-uncoupled electronically controllable sinusoidal oscillator using two VD-DIBAs, two grounded capacitors and two
resistors has been proposed which offers important advantages such as 1) totally uncoupled and electronically con-
trolled condition of oscillation (CO) and frequency of oscillation (FO); 2) low active and passive sensitivities; and 3) a
very good frequency stability factor. The effects of non-idealities of the VD-DIBAs on the proposed oscillator are also
investigated. The validity of the proposed formulation has been confirmed by SPICE simulation with TSMC 0.18 μm
process parameters.
Keywords: Sinusoidal Oscillator; Voltage-Mode; VD-DIBA
1. Introduction
Sinusoidal oscillators find various applications in signal
processing, instrumentation, measurement, communica-
tion and control systems. The class of single resistance
controlled oscillators (SRCOs) using different active
element(s)/device(s) has been of particular interest dur-
ing the last four decades because of their applications in
variable frequency oscillators. However, in these SRCOs,
electronic control of CO and FO can be obtained by re-
placing the respective controlling resistor(s) with FET
based or CMOS voltage controlled resistor(s). A careful
inspection of the available SRCOs reveals that while
many oscillators enjoy independent single element con-
trol of CO and FO, the class of fully uncoupled oscilla-
tors has not been considered adequately in the literature.
In fully uncoupled oscillator circuits CO and FO are de-
termined by two completely different sets of active and/
or passive components, that is none of the active and/or
passive components appeared in CO are involved in FO
and vice versa. This feature is very useful for realizing
voltage controlled oscillators as FO can be controlled
independently without disturbing CO, whereas the flexi-
bility of being able to control CO independently is ad-
vantageous to incorporate amplitude stabilization. In the
recent past, number of fully-uncoupled sinusoidal oscil-
lators employing different active element(s)/devices has
been introduced see [1-7] and the references cited therein.
In references [1-5] the CO and FO of the proposed oscil-
lators are adjustable through resistors (the electronic
tunability can be established by replacing one of the
grounded resistors by JFETs/MOSFETs [8,9]), whereas
in case of oscillators presented in references [6,7], both
CO and FO are electronically controllable. The VD-
DIBA was introduced by Biolek, Senani, Biolkova and
Kolka in [10] since then it has been found to be a useful
new active building block in realizing all voltage-mode
pass filters [11], inductance simulation [12], universal
biquad filter [13] and an electronically controllable sinu-
soidal oscillator [14]. Although the paper presented by
the authors in [14] employs two VD-DIBAs, two grounded
capacitors and one grounded resistor but this circuit does
not have the capability of complete independence of CO
and FO as well as electronic control (only FO is elec-
tronically controllable). Therefore, the purpose of this
*Corresponding author.
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opyright © 2013 SciRes. CS