Font Size: a A A

High-speed communication circuits: Voltage control oscillators and VCO-derived filters

Posted on:2005-11-22Degree:Ph.DType:Dissertation
University:Iowa State UniversityCandidate:Chen, HuitingFull Text:PDF
GTID:1458390008478011Subject:Engineering
Abstract/Summary:
Voltage Controlled Oscillators (VCO) and filters are the two main topics of focus in this dissertation.; A temperature and process compensated VCO, which is designed to operate at 2 GHz, and whose frequency variation due to incoming data is limited to 1% of its center frequency was presented. The test results show that, without process changes present, the frequency variation due to a temperature change over 0°C to 100°C is around 1.1% of its center frequency. This is a reduction of a factor of 10 when compared to the temperature variation of a conventional VCO.; A new method of designing continuous-time monolithic filters derived from well-known voltage controlled oscillators (VCOs) was introduced. These VCO-derived filters are capable of operating at very high frequencies in standard CMOS processes. Prototype low-pass and band-pass filters designed in a TSMC 0.25 mum process are discussed. Simulation results for the low-pass filter designed for a cutoff frequency of 4.3 GHz show a THD of -40 dB for a 200 mV peak-peak sinusoidal input. The band-pass filter has a resonant frequency programmable from 2.3 GHz to 3.1 GHz, a programmable Q from 3 to 85, and mid-band THD of -40 dB for an 80 mV peak-peak sinusoidal input signal.; A third contribution in this dissertation was the design of a new current mirror with accurate mirror gain for low beta bipolar transistors. High mirror gain accuracy is achieved by using a split-collector transistor to compensate for base currents of the source-coupled.
Keywords/Search Tags:Filters, Oscillators, Vco
Related items