The Airborne and Satellite Investigation of Air Quality (ASIA-AQ) is an international field study concept in the active planning stage. The study will implement air quality observations from multiple perspectives (satellite, ground-based, and airborne) in a consistent strategy across selected Asian countries to improve understanding of both specific air quality issues for each location and common challenges in the interpretation of satellite observations and model predictions of air quality. With initial flights planned for early 2024, this paper outlines the basic plans for the study. Ongoing efforts include the development of specific plans for each country that consider the unique conditions and emissions driving local air quality.

A CMOS inverter based amplifier operable down to 0.8 V of power supply has been proposed. The CMOS inverter amplifier has a level shifter circuit at its input to effectively reduce its threshold voltages. The level shift is realized by feeding an input signal via a resistive voltage divider which is connected between VDD and GND. The proposed amplifiers are used to construct a three-stage active RC polyphase filter with 0.3 to 3 MHz passband. The active RC polyphase filter was fabricated in 0.18 mum CMOS technology, and measured results show that the proposed amplifier successfully operates from 0.8 V supply voltage.

A numerical noise analysis method for oscillators is proposed. Noise sources are usually small and can be considered as perturbations to a large amplitude oscillation. Transfer functions from each noise source to the oscillator output can be calculated by modeling the oscillator as a linear periodic time-varying circuit. The proposed method is a time domain method and can be applied to strongly nonlinear circuits. Thermal noise, shot noise and flicker noise are considered as noise sources. Error in the time domain method is also discussed.

One of the excitations, 'carrier', is a large signal and an arbitrary T-periodic function of time. The other excitation, 'signal', is considered as a small perturbation to the periodic steady-state response driven by the carrier. To find a small signal frequency response for the 'signal', the method uses variational equations around the periodic steady-state response. These linearized time-varying differential equations are solved in the frequency domain using a time discretization method. The method can be used to compute the small signal frequency responses of nonideal switched capacitor filters, mixers, and other nonlinear circuits, if the circuit has a stable periodic response. The formulation of the problem, computational complexity of the method, error analysis, sensitivity analysis, implementation of the method, and some applications are covered.>