Finally, the spectrum analyzer is used to measure phase noise. Electrical Engineering and Computer Science. However, the drawback to using a CML buffer is that it requires a constant static current source; thus, it suffers from dissipating more static power than a CMOS inverter [35]. VCO start-up and stability analysis using time varying root locus Sohail, Aneeb. A small signal two-port based approach that is design oriented is presented. This task was not easy as both switched-capacitor turned off and on had to be considered and sufficient overlapping of tuning range must be guaranteed. Permanent address of the item is http:

The VCO with the switched- capacitor turned off will be designed to cover the frequency range of approximately 14 GHz to This can be estimated by two different methods. This measured performance is comparable with state-of-the-art wide-tuning-range VCOs. Voltage-controlled oscillators Wireless sensor networks. This task was not easy as both switched-capacitor turned off and on had to be considered and sufficient overlapping of tuning range must be guaranteed.

When the oscillation stabilizes the frequency is measured to be approximately 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.

Low power low phase noise CMOS LC quadrature voltage-controlled oscillators

The testbench schematic for Design B characterization is provided in Figure 5. Based on the control voltage, the VCO oscillates at a higher or lower frequency, which affects the phase and frequency of the feedback clock. Cvo in the shielded room did not have a noticeable effect on further improving the phase noise.

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]. This section introduces the loop filter and discusses how we designed two loop filters, one for loop bandwidth 1 MHz and the other for loop bandwidth kHz. The loop filter then converts these signals to a control quadraturf that is used to control the VCO.


Because the phase frequency detector is made with real-world components, these gates have delays associated with them.

quadrature vco thesis

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. The main disadvantage to using this configuration is the difficulty in implementing it when the supply voltage is low due to the stacking of transistors.

quadrature vco thesis

One switched-capacitor is used here to have two modes, for a fair comparison with the two-core Design A. In what follows the first-order PLL is first discussed.

Quadrature vco thesis

As integrated photonics and bonding technologies are maturing, commercialization of hybrid-integrated optical links are becoming a reality. These setups are shown in Figure 5.

Note that the overall tuning range quadraturf skewed to allow for frequency drop after post-layout simulation due to parasitic capacitance. Vtune for VCO The first VCO was designed to cover the frequency range It was noticed that during post-layout simulations the total current varied quite a bit for process corners.

Two design cases are presented. The design of the PFD is shown in Figure 6.

Holistic Design In High-Speed Optical Interconnects – CaltechTHESIS

I would not be able to go this far without you. Another quadraturee reason is the presence of parasitic resistance and capacitance which reduces range.

quadrature vco thesis

The first PLL was introduced in and today, decades later, there are still many people researching this circuit [3]. Another importance of the study of wide-tuning range PLLs is that it is a practical method in dealing with environmental and process thesiz.


Due to advantages such as these they are commonly used and have been studied extensively.

The main reason for this popularity is probably the versatility of PLLs [3]. In communication qyadrature a good-quality LO signal for up- and down-conversion in transmitters is needed. 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.

Holistic Design In High-Speed Optical Interconnects

Simulation Results This chapter discusses the transient response and amplitude, the tuning range, and finally the phase noise simulation results of the two GHz LC-VCO designs. A final attempt to improve phase noise was to use a bias-T at Vtune with a battery. In general, the tail current aids the designer in achieving a compromise between phase noise performance and power dissipation. Its low output impedance results in its increased drivability and ability to drive a big load [33].

First, a brief overview of the simulation results without extraction is presented for comparison quadraturre. Closed-loop PLL simulations for two loop bandwidths, 1 MHz and kHz, using a simple charge pump, PFD, loop filter, and Verilog-A divider confirm that thsis time is inversely proportional quadratute bandwidth. Power consumption is measured via the current drawn using a multimeter.