This paper deals with different approaches to design Phase Locked Loop (PLL) frequency synthesizer. PLL system responds to both frequency and phase of the input signals, automatically raising or lowering the frequency of controlled oscillator until it is matched to the reference in both frequency and phase. The performance of PLL frequency synthesizer is improved by using different Voltage cont...

This paper presents a complementary metal-oxidesemiconductor (CMOS) differential voltage-controlled oscillator (VCO) implemented with the push-push principle. The push-push VCO uses two frequency doublers stacked in series with an LC quadrature voltage-controlled oscillator (QVCO) to share the dc current with the QVCO for low power consumption. The proposed CMOS VCO has been implemented with th...

This paper describes the simulations performed in order to evaluate expected performance of the voltage-controlled oscillator (VCO) based on differential ring oscillator with SCFL delay cells in 0.5μm GaAs MESFET technology. The ring oscillator structures with buffer cells are also simulated. The frequency range and tuning sensitivity are extracted. Finally, jitter simulations are performed in ...

This paper presents a new quadrature voltage-controlled oscillator (QVCO), which consists of two p-core Colpitts cross-coupled voltage-controlled oscillators (VCOs) with an LC ring resonator to provide the quadrature outputs. The proposed CMOS QVCO has been implemented with the TSMC 0.18μm CMOS technology and the die area is 0.478×0.82mm2. At the supply voltage of 1.5V, the total power consumpt...

The digital PWM modulator circuit is capable of varying the duty cycle of the output (PWM) according to the digital input word. A digitally controlled current starved pulse width modulator is described. The current from the power grid to the ring oscillator is controlled by a header circuit. By changing the header current, the pulse width of the switching signal generated at the output of the r...