Time and Frequency Division National Bureau of Standards Boulder, Colorado 80303 ;ummary Heretofore, the Allan Variance," u *(r), has become the de facto standard for measudng oscillator instabilitv in the time-domain. Often oscillator frequency instabilities are resonabl modelable with a power law spectrum: S (f) e" where y is the normalized frequency,yf is th; Fourier frequency, and a is a co...

In this study, the impacts of gate recess and passivation on AlGaN/GaN high electron mobility transistors (HEMTs) were investigated. The trap-related characteristics were studied in detail by several different measurements including dc current– voltage, current collapse, gate lag, and flicker noise characterizations. With a Cl2/Ar-recessed gate, drain current collapse factors ( Imax) of 37:5 an...

Assessing and comparing the performance of watermarking algorithms is difficult. The visibility of the watermark is an important aspect in this process. In this paper, we propose two metrics for evaluating the visual impact of video watermarks. Based on several different watermarking algorithms and video sequences, we identify the most prominent impairments as spatial noise and temporal flicker...

A harmonic mixer for direct-conversion receivers is proposed and fabricated in a CMOS process. It is immune from both the flicker noise and self-mixing induced DC offset. Using the lateral bipolar transistor and the harmonic mixing technique, it achieves +15dB gain, 17.8dB NF at 10kHz frequency, 8.2dBm IIP3, +44dBm IIP2 and more than 30dB DC offset suppression. It consumes 2.2mW power at 3V.

This paper describes the issues and tradeoffs in the design and monolithic implementation of direct-conversion receivers and proposes circuit techniques that can alleviate the drawbacks of this architecture. Following a brief study of heterodyne and image-reject topologies, the direct-conversion architecture is introduced and effects such as dc offset, I=Q mismatch, even-order distortion, flick...

A fully differential opamp suitable for very-low voltage switched-capacitor circuits in standard CMOS technologies is introduced. The proposed two stage opamp needs a simple low voltage CMFB switched-capacitor circuit only for the second stage. Due to the reduced supply voltage, the CMFB circuit is implemented using bootstrapped switches. Minor modifications allow to use chopper stabilization f...