The switches must be implemented as MOS transistors, which have series resistance when on, as well as parasitic capacitance to the substrate from their drain and source regions. This can be estimated by two different methods. In general, the tail current aids the designer in achieving a compromise between phase noise performance and power dissipation. The design implemented is the same as that discussed in Section 6. As experimental test devices, over forty monolithic inductors and thirty varactors have been implemented, measured and modeled.

As indicated, at 1 MHz offset, the phase noise is — Two loop filters are designed, one for loop bandwidth approximately 1 MHz and another for loop bandwidth approximately KHz. To solve this problem, the tail current source is sometimes removed, such as in [14], thus leaving more voltage headroom for the active devices to operate in the saturation region. Each differential input variable is connected to a differential pair circuit. Finally, this chapter discusses some future work that could improve the current work. Phase noise can also be defined as follows: The combined task of the PFD, charge pump, and loop filter blocks is to provide a stable DC tuning voltage to the VCO based on the frequency and phase difference between the reference frequency and output of the divider so that acquisition of the PLL can be achieved.

Abstract Integrated circuit scaling has enabled a huge growth in processing capability, which necessitates a corresponding increase in inter-chip communication bandwidth. To solve this problem, the tail current source is sometimes removed, such as in [14], thus leaving more voltage headroom for the active devices to operate in tuesis saturation region.

Quadrature vco thesis

The other noise mechanism is thermal noise thssis is due to the thermal excitation of charge carriers in a conductor. 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]. It was noticed that during post-layout simulations the total current varied quite a bit for process corners.


Eliminating dead zone is important for accurate frequency generation and low phase noise in frequency synthesizer PLLs [50].

The aspect ratio of the cross-coupled NMOS transistor of the VCO cores varied quite a bit from the calculated value which provided a guideline. For a given current, this complementary topology offers higher transconductance. Kluwer Academic Publishers, For symmetry, the 32 tthesis block is implemented using two capacitors and two transistors.

A study of two wideband CMOS LC-VCO structures – UBC Library Open Collections

Phase Noise in Oscillators. The design consists thesix one VCO core with a switched-capacitor which can be switched on or off, creating overlapping tuning ranges.

Next, on the optical transmitter side, three new techniques will be presented. This will be further discussed in Chapter 3.

quadrature vco thesis

M1 will then inject currents into the bias loop, starting up the circuit. Kluwer 73 Academic Publishers, It is shown that a source-synchronous receiver with MSK modulation is a suitable choice for eliminating the crystal in WSN applications.

Integrated RF oscillators and LO signal generation circuits

A low pass filter may be needed for additional rejection of reference sidebands called spurs [58]. It is important to note that the order of the PLL is determined by the highest power of s in the denominator of the transfer function. Both PMOS- and NMOS-only topologies can provide an output voltage swing greater than the voltage supply with the help of a high tail- 8 current feed-through.

The implemented design of qhadrature CML stage is shown in Figure 3. Its low output impedance results in its increased drivability quasrature ability to drive a big load [33]. This is followed by a power generation method based fast start-up analysis of resonator based oscillators.

The VCO with the switched- capacitor turned off will be designed to cover the frequency range of approximately 14 GHz to Another reason the CML stage is ideal for this design is because it is a high-speed logic circuit.


Quadrature vco thesis

By extending the linear portion of this curve to the x-axis, the point where it crosses the x-axis is the approximation of VTH. However, the digital logic system that controls the switching of the switched-capacitor must be carefully quadratjre in the design in order to guarantee stability over the complete tuning range [31].

Yordanov, “Wireless inter-chip and intra-chip communication,” in Microwave Conference European,pp.

quadrature vco thesis

It can act not only as a phase detector but also as a frequency detector, detecting both phase and frequency difference between two signals and generating an output that represents that difference [47]. There are many different analysis methods of analyzing the start-up and frequency stability of a system, but mostly it fails to analyze properly due to qusdrature parasitics involved.

Finally, we have a look at the entire VCO with all of these blocks together. Being a fco building block of the PLL, the VCO performs essential functions in the transmission of and reception of data. Uqadrature consumption is measured via the current drawn using a multimeter. This dissertation focuses on the analysis, design, and application of inductor-capacitor LC oscillators for wireless sensor networks WSNs.

A review of the measured performance of the two designs is shown in Table 7. C1 and C2 are designed so their impedance over the frequency range of interest is substantially smaller compared to R1 and R2; thus, Vci voltage drop across the capacitors is insignificant compared to the voltage drop across the resistors.