This paper introduces a new voltage-mode second-order sinusoidal generator circuit with four active elements and six passive elements, including grounded capacitors. The frequency and condition of oscillation can be independently controlled. The effect of active element’s nonidealities and parasitic effects is also studied; the proposed topology is good in absorbing several parasitic elements involved with the active elements. The circuit is advantageous for generating high frequency signals which is demonstrated for 25 MHz outputs. Several circuit extensions are also given which makes the new proposal useful for real circuit adoption. The proposed theory is validated through simulation results.

Four-phase sine-wave generators with voltage outputs progressively separated by 90° apart find useful applications in communication and instrumentation systems and hence have been well covered in open literature [

This work is based on the realization of four-phase voltage-mode oscillator employing band-pass filter as reported in a recent work [

The proposed voltage-mode four-phase sinusoidal generator circuit is based on DVCCs, whose symbol and circuitry are shown in Figure

Differential voltage current conveyor with

Basic scheme of oscillator realization.

Proposed four-phase oscillator circuit.

The circuit of Figure

A nonideal DVCC is characterized by the following relationship:

Here, the voltage transfer gains from

The four-phase oscillator of Figure

Voltage outputs of the proposed circuit.

Fourier spectrum of outputs with FO = 10.25 MHz.

Fourier spectrum for different “

This section presents some useful circuit extensions by simple modifications to the proposed circuit of Figure

The voltage-mode four-phase oscillator of Figure

Quadrature current outputs for extended circuit.

Fourier spectrum of the current outputs with FO = 10.25 MHz.

Circuit with simpler configuration can be obtained by leaving the

Another circuit enhancement is the use of voltage controlled DVCC as was introduced in [

Very interesting circuit advancement can be obtained by employing current gain variable DVCCs. It may be noted that conventional DVCC has unity current transfer gain from

A last future enhancement is the use of a digitally controlled current transfer gain stage, which has been recently employed in some work [

The topic of this paper assumes significance in light of some interesting works which continue to appear till recently in the open literature [

The paper deals with a new proposal for voltage-mode four-phase oscillator circuit with independent control of FO as well as CO and use of grounded capacitors and a circuit topology suited to minimizing the parasitic effects and applicability to high frequency. Nonideal and parasitic study is also given. Some useful circuit extensions for a simpler topology, for simultaneous four-phase current outputs, voltage/current tunable oscillator, and digitally controlled circuit are also given. The new proposals are enrichment to the available knowledge on the subject.

The author is thankful to the anonymous reviewers for positive feedback on the paper. The author also thanks Professor Ali Umit Keskin, Academic Editor, for recommending the paper.