7 research outputs found
High performance RF and baseband building blocks for wireless receivers
Because of the unique architecture of wireless receivers, a designer must
understand both the high frequency aspects as well as the low-frequency analog
considerations for different building blocks of the receiver. The primary goal of this
research work is to explore techniques for implementing high performance RF and
baseband building blocks for wireless applications. Several novel techniques to improve
the performance of analog building blocks are presented. An enhanced technique to
couple two LC resonators is presented which does not degrade the loaded quality factor
of the resonators which results in an increased dynamic range.
A novel technique to automatically tune the quality factor of LC resonators is
presented. The proposed scheme is stable and fast and allows programming both the
quality factor and amplitude response of the LC filter.
To keep the oscillation amplitude of LC VCOs constant and thus achieving a
minimum phase noise and a reliable startup, a stable amplitude control loop is presented.
The proposed scheme has been also used in a master-slave quality factor tuning of LC
filters.
An efficient and low-cost architecture for a 3.1GHz-10.6GHz ultra-wide band
frequency synthesizer is presented. The proposed scheme is capable of generating 14A novel pseudo-differential transconductance amplifier is presented. The
proposed scheme takes advantage of the second-order harmonic available at the output
current of pseudo-differential structure to cancel the third-order harmonic distortion.
A novel nonlinear function is proposed which inherently removes the third and
the fifth order harmonics at its output signal. The proposed nonlinear block is used in a
bandpass-based oscillator to generate a highly linear sinusoidal output.
Finally, a linearized BiCMOS transconductance amplifier is presented. This
transconductance is used to build a third-order linear phase low pass filter with a cut-off
frequency of 264MHz for an ultra-wide band receiver.
carrier frequencies
An Accurate Automatic Quality-Factor Tuning Scheme for Second-Order LC Filters
This paper presents a scheme to accurately tune the quality factor of second-order LC bandpass filters. The information of the magnitude response at the center and one of the cutoff frequencies is used to tune both the amplitude and the quality factor of the filter using two independent yet interacting loops. Furthermore, the synergic interaction between the loops makes the proposed scheme stable and insensitive to the mismatch between the input amplitudes. A chip prototype was implemented in a 0.35-mum CMOS process and consumes 4.3 mA from a single 1.3-V supply. Measurement results show that at 1.97 GHz the quality factor is tunable from 60 to 220 while the amplitude is tunable between -15 and 0 dBm with worst case quality factor and amplitude tuning accuracies of 10% and 7%, respectivel
HIGH PERFORMANCE RF AND BASEBAND BUILDING BLOCKS Approved by: FOR WIRELESS RECEIVERS
Because of the unique architecture of wireless receivers, a designer must understand both the high frequency aspects as well as the low-frequency analog considerations for different building blocks of the receiver. The primary goal of this research work is to explore techniques for implementing high performance RF and baseband building blocks for wireless applications. Several novel techniques to improve the performance of analog building blocks are presented. An enhanced technique to couple two LC resonators is presented which does not degrade the loaded quality factor of the resonators which results in an increased dynamic range. A novel technique to automatically tune the quality factor of LC resonators is presented. The proposed scheme is stable and fast and allows programming both the quality factor and amplitude response of the LC filter. To keep the oscillation amplitude of LC VCOs constant and thus achieving a minimum phase noise and a reliable startup, a stable amplitude control loop is presented. The proposed scheme has been also used in a master-slave quality factor tuning of LC filters
An Accurate Automatic Quality-Factor Tuning Scheme for Second-Order LC Filters
Abstract—This paper presents a scheme to accurately tune the quality factor of second-order LC bandpass filters. The information of the magnitude response at the center and one of the cutoff frequencies is used to tune both the amplitude and the quality factor of the filter using two independent yet interacting loops. Furthermore, the synergic interaction between the loops makes the proposed scheme stable and insensitive to the mismatch between the input amplitudes. A chip prototype was implemented in a 0.35- m CMOS process and consumes 4.3 mA from a single 1.3-V supply. Measurement results show that at 1.97 GHz the quality factor is tunable from 60 to 220 while the amplitude is tunable between 15 and 0 dBm with worst case quality factor and amplitude tuning accuracies of 10 % and 7%, respectively. Index Terms—Automatic-tuning, CMOS circuits, LC bandpass filter,-enhancement