scholarly journals Nonlinearity Minimums and Maximums of a Phase-Sensitive Detection System

1970 ◽  
Vol 19 (1) ◽  
pp. 25-27
Author(s):  
Branko Leskovar
Keyword(s):  
Detection System ◽  
Sensitive Detection ◽  
Phase Sensitive ◽  
Phase Sensitive Detection

scholarly journals Current/Voltage Controlled Quadrature Sinusoidal Oscillators for Phase Sensitive Detection Using Commercially Available IC

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1319 ◽  
Author(s):  
Winai Jaikla ◽  
Suchin Adhan ◽  
Peerawut Suwanjan ◽  
Montree Kumngern
Keyword(s):  
Detection System ◽  
Phase Error ◽  
Harmonic Distortion ◽  
Sensitive Detection ◽  
Frequency Error ◽  
Sinusoidal Oscillators ◽  
Sinusoidal Oscillator ◽  
Condition Of Oscillation ◽  
Phase Sensitive ◽  
Phase Sensitive Detection

This paper presents the quadrature sinusoidal oscillators for a phase sensitive detection (PSD) system. The proposed oscillators are design by using the commercially available ICs (LT1228). The core oscillator consists of three LT1228s: two grounded capacitors and one resistor. By adding four resistors without the requirement of additional active devices, the amplitudes of two quadrature waveforms become adjustable. The quadrature output nodes are of low impedance, which can be connected to the impedance sensor or other circuits in a phase sensitive detection system without the need of buffer devices. The amplitudes of the quadrature waveform are equal during the frequency of oscillation (FO) tuning. The frequency of oscillation is electronically and linearly controlled by bias current or voltage without affecting the condition of oscillation (CO). Furthermore, the condition of oscillation is electronically controlled without affecting the frequency of oscillation. The performances of the proposed oscillators are experimentally tested with ±5 voltage power supplies. The frequency of the proposed sinusoidal oscillator can be tuned from 8.21 kHz to 1117.51 kHz. The relative frequency error is lower than 3.12% and the relative phase error is lower than 2.96%. The total harmonic distortion is lower than −38 dB (1.259%). The voltage gain of the quadrature waveforms can be tuned from 1.97 to 15.92. The measurement results demonstrate that the proposed oscillators work in a wide frequency range and it is a suitable choice for an instrument-off-the-shelf device

scholarly journals CO2 Methanation over Rh/CeO2 Studied with Infrared Modulation Excitation Spectroscopy and Phase Sensitive Detection

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 601
Author(s):  
Felix Hemmingsson ◽  
Andreas Schaefer ◽  
Magnus Skoglundh ◽  
Per-Anders Carlsson
Keyword(s):  
Reaction Pathway ◽  
Sensitive Detection ◽  
Side Reactions ◽  
Co2 Methanation ◽  
Individual Contributions ◽  
Phase Sensitive ◽  
Phase Sensitive Detection ◽  
Modulation Excitation Spectroscopy ◽  
Modulation Excitation

Methane is a well-established fuel molecule whose production from CO 2 through methanation garners increasing interest as an energy storage solution. While often produced with Ni based catalysts, other metals are of interest thanks to higher robustness and activity-selectivity numbers. The Rh/CeO 2 catalyst has shown appreciable properties for CO 2 methanation and its structural dynamics has been studied in situ. However, the reaction pathway is unknown. Here, we present infrared modulation excitation spectroscopy measurements with phase sensitive detection of a Rh/CeO 2 catalyst adsorbate composition during H 2 pulsing (0–2 vol.%) to a constant CO 2 (0.5 vol.%) feed. Various carbonyl (CO) and carbonate (b-CO 3 /p-CO 3 ) ad-species clearly respond to the hydrogen stimulus, making them potential reaction intermediates. The different CO ad-species are likely intermediates for product CO and CH 4 but their individual contributions to the respective formations are not unambiguously ascertained. As for the carbonate dynamics, it might be linked to the reduction/oxidation of the CeO 2 surface upon H 2 pulsing. Formate (HCOO) ad-species are clearly visible but appear to be, if not spectators, linked to slow side reactions possibly also affected by CeO 2 redox processes.

scholarly journals Phase-Sensitive Detection for Optical Sensing With Porous Silicon

2012 ◽  
Vol 4 (3) ◽  
pp. 986-995 ◽  
Author(s):  
J. Alvarez ◽  
N. Kumar ◽  
P. Bettotti ◽  
D. Hill ◽  
J. Martinez-Pastor
Keyword(s):  
Porous Silicon ◽  
Optical Sensing ◽  
Sensitive Detection ◽  
Phase Sensitive ◽  
Phase Sensitive Detection
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