Related Experiment Video
Updated: Feb 14, 2026

Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas
Published on: November 24, 2017
Using a Second Order Sigma-Delta Control to Improve the Performance of Metal-Oxide Gas Sensors
Lukasz Kowalski1, Joan Pons-Nin2, Eric Navarrete3
1Micro and Nano Technologies Group, Electronic Engineering Department, Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain. lukasz.kowalski@upc.edu.
Abstract:
Controls of surface potential have been proposed to accelerate the time response of MOX gas sensors. These controls use temperature modulations and a feedback loop based on first-order sigma-delta modulators to keep constant the surface potential. Changes in the surrounding gases, therefore, must be compensated by average temperature produced by the control loop, which is the new output signal. The purpose of this paper is to present a second order sigma-delta control of the surface potential for gas sensors. With this new control strategy, it is possible to obtain a second order zero of the quantization noise in the output signal. This provides a less noisy control of the surface potential, while at the same time some undesired effects of first order modulators, such as the presence of plateaus, are avoided. Experiments proving these performance improvements are presented using a gas sensor made of tungsten oxide nanowires. Plateau avoidance and second order noise shaping is shown with ethanol measurements.
Related Concept Videos
The Delta-to-Delta Circuit
Alkali Metals
Table 1: Properties of the alkali metals
Oxidation Numbers
The Y-to-Delta Circuit
The initial step in analyzing a wye-to-delta circuit is to assume a positive phase sequence. These phase voltages are then utilized to calculate the line voltages that occur directly across the delta-connected load impedances. Van, Vbn, and Vcn are the phase voltages in wye, and Vab, Vbc, and Vca are the line voltages for a delta circuit. The relation between...
The Delta-to-Y Circuit
Properties of Transition Metals

