Effects of Timing Noise on Square-Wave Optoelectronic Oscillators

Optoelectronic oscillators produce microwave-modulated optical beams without external modulation. The most commonly studied types produces narrow-band output, i.e., optical output modulated by a sinusoid, in which case phase noise determines key figures of merit that limit device performance. Nonetheless, other types of modulated signals have been exhibited by optoelectronic oscillators, including square waves. In this work we provide a theoretical treatment of the power spectral density of a microwave self-modulated optical periodic, but non-sinusoidal, oscillator in the presence of timing noise (as phase noise is only defined for a single sinusoid) and focus on the case of square waves. We consider the effects of timing noise on the power spectral density and autocorrelation function of the modulation signal.

A Current Mode Universal Filter and a Single Resistance Controlled Oscillator Employing only Grounded Passive Elements: Applications of VDCC

This research article explores the possible applications of voltage differencing current conveyor (VDCC), as a current mode universal filter and a sinusoidal oscillator. Without the need for an additional active/passive element, a very simple hardware modification makes it a dual-mode quadrature oscillator from the filter configuration. Both the proposed circuit requires only two VDCC and all grounded passive elements, hence a preferable choice for integration. The filter has some desirable features such as availability of all five explicit outputs, independent tunability of filter parameters. Availability of explicit quadrature current outputs, independence in start and frequency of oscillations, makes it a better oscillator design. Apart from prevalent CMOS simulation results, VDCC is also realized and experimentally tested using the off-the-shelf integrated circuit. All the pen and paper analysis such as non-ideal, sensitivity and parasitic analysis supports the design.

New Electronically Tunable Third Order Filters and Dual Mode Sinusoidal Oscillator Using VDTAs and Grounded Capacitors

This study introduces a third order filter and a third order oscillator configuration. Both the circuits use two voltage difference transconductance amplifiers (VDTAs) and three grounded capacitors. By selecting the input and output terminals properly, current mode and transimpedance mode low-pass and band-pass filters can be obtained without component matching conditions. The natural frequency (ω0) can be tuned electronically. The oscillator circuit provides voltage and current outputs explicitly. The condition of oscillation (CO) and the frequency of oscillation (FO) can be adjusted orthogonally and electronically. The workability of the configurations is judged using TSMC CMOS 0.18 μm technology parameter as well as commercially available LM13700 integrated circuits (ICs). The simulation results show that: for ±0.9V power supply, the power consumption is 1.08 mW for both the configurations, while total harmonic distortions (THDs) are less than 2.06% and 2.17% for the filter and oscillator configurations, respectively.

MOS-C Based Electronically Tuneable Current/Voltage-Mode Third Order Quadrature Oscillator and Biquadratic Filter Realization

This paper introduces a new electronically tuneable third order quadrature oscillator and biquadratic filter with MOS-C realization using all grounded passive components. Voltage-mode second order low-pass, high-pass, band-pass filters using second generation current conveyor and a current/voltage-mode third order quadrature sinusoidal oscillator using multi-output second generation current conveyor are synthesized from the proposed circuit topology. All synthesized circuits are compatible with integration and the center frequency can be electronically tuned by the gate voltage of the MOS transistors. The proposed circuits do not need any component matching condition. Oscillation condition and frequency of oscillation can be independently controlled. Workability of the proposed circuits is validated by PSPICE software using 0.18 micrometer MOSIS CMOS process parameters at ±0.9 V supply voltage. Tuneability of the oscillator is demonstrated for a tested frequency range both in voltage-mode and current-mode operations.

A Practical Fractional-Order Sinusoidal Oscillator Design and Implementation

In this study, a new sinusoidal fractional oscillator circuit in which the fractional low-pass filter and fractional differentiator form a closed loop has been introduced. The single series [Formula: see text] pair and Valsa method have been used to imitate the fractional-order capacitor. Two different sinusoidal signals with different phases are available at output ports. An integer version of the proposed oscillator is not possible, only the fractional version is valid, that is a noticeable feature. The introduced circuit has been simulated by employing SPICE software. The proposed fractional oscillator is also verified by implementing circuit with AD817ANs and passive components, experimentally.