This paper presents phase noise behaviour and design aspects of PLL based frequency synthesizers with ∆Σ dithering for cognitive multi-radio mobile terminals. Principal features of PLL based frequency synthesizers and 1-bit ∆Σ dithering are presented and simulated. Moreover, frequency synthesizer requirements for main standards in the frequency band 800 MHz to 6 GHz are investigated as well.

1 The growing importance of wireless media for voice and data communications is driving a need for higher integration in personal communications transceivers in order to achieve lower cost, smaller form factor, and lower power dissipation. One approach to this problem is to integrate the RF functionality in low-cost CMOS technology together with the baseband transceiver functions. This in turn ...

To realize the lagging behavior in heat conduction observed in these two decades, this paper firstly theoretically excludes the possibility that the underlying thermal inertia is a result of the time delay in heat diffusion. Instead, we verify in experiments the electro-thermal analogy, wherein the thermal inertial is parameterized by thermal inductance that formulates hyperbolic heat-conductio...

Fractional-N PLL is an essential part of modern wireless communication systems. The ever-increasing demand for higher data transfer rates while operating in heavily crowded frequency bands demands top-notch performance from the frequency synthesizers. In order to satisfy the tough requirements put forth by modern communication standards, researchers around the world have examined many innovativ...

a 0.4-pm digit l CMOS technology entails many difficulties This paper describes the design of a CMOS frequency synthesizer targeting wireless local area network applications in the 5-GHz range. Based on an integer-N architecture, the synthesizer produces a 5.2-GHz output as well as the quadrature phases of a 2.6-GHz carrier. Fabricated in a 0.4-pm digital CMOS technology, the circuit provides a...

This paper discussed the circuit level design and simulation of fractional-N frequency divider, a circuit block used mainly in frequency synthesizer. The design was done in schematic level. A low power 0.5 micron CMOS technology called CMOSIS5 used for modeling the circuit devices. The frequency divider was design for 900 MHz GSM standard mobile communication application. For the simulation, ci...