This will be elaborated in Chapter 7. Monolithic coils and variable capacitors are essential, and this thesis deals with good structures of these devices and their proper modeling. These high-frequency VCO designs belong to 2 the state-of-the-art and are worthwhile to examine. At low frequencies, CMOS is preferred for its simplicity and low static power dissipation, but at higher frequencies, CML is used as it is faster with lower power due to its reduced output swing [36]. It was noticed that during post-layout simulations the total current varied quite a bit for process corners. The architectural advantages are described along with an analysis for the oscillation frequency.

An application of this analysis to the design optimization of LC oscillators is also demonstrated. This thesis tackles these challenges by presenting a detailed study of LC oscillators, monolithic elements for good-quality LC resonators, and circuits for IQ-signal generation and for frequency conversion, as well as many experimental circuits. The VCO with the switched- capacitor turned off will be designed to cover the frequency range of approximately 14 GHz to Being a critical building block of the PLL, the VCO performs essential functions in the transmission of and reception of data. The operation of the CML buffer is based on the differential pair circuit.

The proper design of the loop filter is also important for the stability of the PLL loop [55].

quadrature vco thesis

As can be seen in Figure 6. Power consumption is measured via the current drawn using a multimeter.

A novel low voltage quadrature LC oscillator with a fast start-up is then presented. As experimental test devices, over forty monolithic inductors and thirty varactors have been implemented, measured and modeled. This thesis deals with fully integrated LC oscillators and local oscillator LO signal generation circuits. To load this item in other compatible viewers, use this url: The following equations are used to estimate the values of C1, C2, C3, R2, and R3 in the third- order loop filter shown in Figure 6.


Frequency conversion circuits are used for alleviating qaudrature problems or to expand the number tbesis frequency bands covered. Corner analysis is performed to observe the sensitivity of the thesi designs to process variations.

This can be explained by the fact that for Design B, the switched- capacitor is placed in parallel with the LC-tank which decreases the Q of the LC-tank. Resource Type Dissertation Date available T As can be seen, both designs are quite robust to quafrature variations.

My phase noise simulations indicated the dominance of flicker noise, although thermal noise did occur at times.

quadrature vco thesis

Well-designed, high-quality oscillators are normally very amplitude stable, so a t can be considered constant over time. Cambridge University Press, It is important for PLLs to have dead zone elimination circuitry to ensure that the charge pump always comes on for some amount of time to avoid operating in the dead zone [49]. The balanced symmetrical design of the switched-capacitor has a common-mode node and allows for better linearity and phase noise performance compared to a switched-capacitor with no common-mode node [31].

A simple model of the charge pump circuit together with a capacitor representing the loop filter is shown in Figure 6. To ensure loop stability, we must locate the point of minimum phase shift at the unity gain frequency of the open loop response as shown in Figure 6. Doctor of Philosophy Ph. A list of test equipment required to perform the tests is provided. These setups are shown in Figure 5.


Several MOSFET oscillator architectures have been analyzed and the start-up times compared using this analysis with applications to start-up time reduction quzdrature LC oscillators. A small signal two-port based approach that is design oriented is presented.

The phase noise could be improved by methods such as: However, the amplitude for PMOS is smaller and therefore the phase noise worse [1]. Next, on the optical transmitter side, three new techniques will be presented.

Quadrature vco thesis

Abstract The oscillator circuit is one of the key components of the communication systems. The ring oscillator provides a wider tuning range compared to a monolithic implementation of an Quuadrature [5]. One switched-capacitor is used here to have two modes, for a fair comparison with the two-core Design A. An application of this analysis to the design optimization of LC oscillators is also demonstrated.

Quadrature vco thesis

The most important specifications of the oscillator are the phase noise, the tuning range, the power consumption, and the cost [1]. Because both of these elements constitute a passive filter, the phase noise is low [1]. However, the drawback to using a CML buffer is thesks it requires a constant static current source; thus, it suffers from dissipating more static power than a CMOS inverter [35].