Voltage controlled oscillators are essential building blocks in communication systems and are used as local oscillators to up and down-convert signals in an RF mixer. Despite the continuous improvement in the state of the art of CMOS VCO’s, they still remain the most critical blocks of RF transceivers. The most important parameters of a VCO are phase noise, power consumption and frequency tunin...

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...

There has recently been increasing interest in developing highly digital analog-to-digital converter (ADC) structures for on-chip testing and ease of integration in future CMOS processes. An intriguing circuit to utilize in such cases is a ring oscillator voltage-controlled oscillator (VCO), which outputs a clock waveform whose frequency is a function of an input tuning voltage. By comparing th...

This paper presents the design of five-stage current controlled inductor-less ring oscillator that were simulated in Silterra 0.18um CMOS Technology with oscillation frequencies up to 5.99 GHz. The design uses cross coupled MOS devices along with active inductor (thus inductorless) and controlled by current source to aid in switching speed and to improve the noise parameters. The simulations sh...

A new CMOS LC Voltage Controlled Oscillator (VCO) for IEEE 802.11a application with low phase noise and consumed power less than 1mW is presented. This circuit was taped out by TSMC 0.18um 1P6M process. The measured phase noise is -115-88dBc/Hz at 1MHz offset at the operation frequency of 5.815GHz. And the dc core current consumption is 0.71mA at a supply voltage of 1.4 V. Its figure of merit (...

This article presents a current-mode quadrature oscillator. The proposed oscillator can provide 2 sinusoidal output currents with 90 0 phase difference. It also provides high output impedances that make the circuit able to directly drive load without additional current buffer. The condition of oscillation and frequency of oscillation can be controlled independently and electronically by adjusti...

We propose an analog current-mode subthreshold CMOS circuit implementing a piecewise linear neuromorphic oscillator. Our circuit was derived from a piecewise linear oscillator model proposed by Matsuoka, well known as a building block for constructing a robot locomotion controller. We modified Matsuoka’s oscillator to be suitable for analog current-mode integrated circuit implementation, and de...

In this paper, an ultra low power and low jitter 12bit CMOS digitally controlled oscillator (DCO) design is presented. Based on a ring oscillator implemented with low power Schmitt trigger based inverters. Simulation of the proposed DCO using 32nm CMOS Predictive Transistor Model (PTM) achieves controllable frequency range of 550MHz~830MHz with a wide linearity and high resolution. Monte Carlo ...

We report a novel oscillator for photonic RF systems. This oscillator is capable of generating high-frequency signals up to 70 GHz in both electrical and optical f domains and is a special voltage-controlled oscillator with an optical output port. It can be used to make a phase-locked loop (PLL) and perform all functions that a PLL is capable of for photonic systems. It can be synchronized to a...

A completely monolithic high-Q oscillator, fabricated via a combined CMOS plus surface micromachining technology, is described, for which the oscillation frequency is controlled by a polysilicon micromechanical resonator with the intent of achieving high stability. The operation and performance of micromechanical resonators are modeled, with emphasis on circuit and noise modeling of multiport r...