scholarly journals Long Term Stable Δ-Σ NDIR Technique Based on Temperature Compensation

2019 ◽  
Vol 9 (2) ◽  
pp. 309 ◽  
Author(s):  
Chih-Hsiung Shen ◽  
Jun-Hong Yeah
Keyword(s):  
Temperature Compensation ◽  
Feedback System ◽  
Temperature Drift ◽  
Gas Concentration ◽  
Long Term Stability ◽  
Startup Time ◽  
Loop Feedback ◽  
Infrared Heater ◽  
Previous Design

For a fast and long term stable Non Dispersive Infrared (NDIR) technology of gas concentration measurement, the temperature compensation is required. A novel proposed Δ-Σ NDIR system was investigated and built with a closed-loop feedback system to stabilize the signal readings without temperature drift. The modulation of the infrared heater gives a corresponding signal of gas concentration based on our proposed Δ-Σ conversion algorithm that was affected by the drift of temperatures for the infrared sensor. For our study, a new temperature compensation model was built and verified that formulates the relationship between gas concentration and temperature of sensor. The results show that our proposed Δ-Σ can measure efficiently with half of the startup time than our previous design and maintain long term stability.

New Technologies for Submillimeter Laser Ranging

2011 ◽  
Vol 301-303 ◽  
pp. 397-401
Author(s):  
Josef Blazej ◽  
Ivan Prochazka ◽  
Jan Kodet ◽  
Petr Panek
Keyword(s):  
New Technologies ◽  
System Stability ◽  
Laser Ranging ◽  
Single Shot ◽  
Temperature Drift ◽  
Submillimeter Laser ◽  
Term Stability ◽  
Long Term Stability ◽  
Timing System

We are presenting the work progress and recent results in a development and construction of new technologies for submillimeter laser ranging and picosecond accuracy laser time transfer. The key hardware components: the Start detector and discriminator, the echo signal detector, the timing device and signal cablings were studied in detail. The new devices have been designed, built and tested in our lab. To minimize the systematic errors the photon counting approach has been selected. The ranging chain has been designed and optimized with a goal of single shot resolution of several millimeters and sub-millimeter normal points and overall system stability. The Start detector and discriminator are constructed as a single device to optimize their matching and maintain stability. The NPET timing system based on surface acoustic wave interpolator has a resolution of 800 fs and 4 fs long term stability. The echo detector is based on innovated SPAD detector optimized for high repetition Gate rate and minimal dark count rate. Both the detectors output signals have ultrafast slew rates < 200 ps / 1 V. In connection to the 6 GHz bandwidth of the timing system inputs these fast slew rates improves the timing and temperature stability along with the RF interference immunity. The new low temperature drift signal cables have been selected, tested and used. The new hardware was tested in indoor calibration experiments. We have achieved the single shot resolution of 3 mm rms. The temperature and temporal stability of the individual components is excellent. The drift is typically below 200 fs/K for each contributor. The overall temperature drift of the entire laser ranging chain is below 500 fs/ K. The long term stability of the ground target calibration is better than ± 800 fs within 3 days. During this period the environment temperature changed by more than 4°C. In the sense of time deviation Tdev the stability of 300 fs was achieved. The presented components will enable to carry out laser ranging with submillimeter normal points stability and reproducibility. The accuracy of the “ranging machine” based on these devices will reach sub-mm values, as well. The concept and construction will be presented along with the achieved devices parameters.

scholarly journals An Improved Difference Temperature Compensation Method for MEMS Resonant Accelerometers

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1022
Author(s):  
Pengcheng Cai ◽  
Xingyin Xiong ◽  
Kunfeng Wang ◽  
Jiawei Wang ◽  
Xudong Zou
Keyword(s):  
Temperature Compensation ◽  
Dynamic Range ◽  
Compensation Method ◽  
Frequency Drift ◽  
Long Term Stability ◽  
Frequency Output ◽  
Resonant Accelerometer ◽  
Difference Temperature ◽  
Higher Sensitivity

Resonant accelerometers are promising because of their wide dynamic range and long-term stability. With quasi-digital frequency output, the outputs of resonant accelerometers are less vulnerable to the noise from circuits and ambience. Differential structure is usually adopted in a resonant accelerometer to achieve higher sensitivity to acceleration and to reduce common noise at the same time. Ideally, a resonant accelerometer is only sensitive to external acceleration. However, temperature has a great impact on resonant accelerometers, causing unexcepted frequency drift. In order to cancel out the frequency drift caused by temperature change, an improved temperature compensation method for differential vibrating accelerometers without additional temperature sensors is presented in this paper. Experiment results demonstrate that the temperature sensitivity of the prototype sensor is reduced from 43.16 ppm/°C to 0.83 ppm/°C within the temperature range of −10 °C to 70 °C using the proposed method.

Research on Small-Capacity Capacitor Type Sensor Detection Method

2014 ◽  
Vol 981 ◽  
pp. 594-597
Author(s):  
Wei Tong Hu ◽  
Yu Xuan Zhang ◽  
Yan Sun ◽  
Wang Sheng Liu ◽  
Li Zhong Zhang
Keyword(s):  
Capacitance Measurement ◽  
Capacitive Sensors ◽  
Measurement Circuit ◽  
Temperature Drift ◽  
Long Term Stability ◽  
Value Range ◽  
Special Circumstances ◽  
Output Capacitance ◽  
Sensor Detection

In the field of industrial measurement, capacitive sensors are widely used. In many types of capacitive sensors, the output capacitance value range of many sensors is very small, generally between 10pF to 1000pF, but accuracy is usually required to be more than one thousandth. The conventional method of detecting capacitance value is generally the capacitor charge and discharge. By charging and discharging time statistics and calculations, capacitance values are deduced finally. The inherent disadvantages of this method are: (1) Temperature drift of the measurement circuit is large. (2) The spatial magnetic field under special circumstances impact on measurement circuit. (3) Long-term stability of the device will deteriorate. In this paper, a "capacitance measurement method with reference and comparison" is summed up through a lot of measurement experiments of humidity capacitance, that method can eliminate three kinds of defects in the capacitor charging and discharging process.

Stability and Change in Emotional Intelligence: Exploring the Transition to Young Adulthood

2005 ◽  
Vol 26 (2) ◽  
pp. 100-106 ◽  
Author(s):  
James D.A. Parker ◽  
Donald H. Saklofske ◽  
Laura M. Wood ◽  
Jennifer M. Eastabrook ◽  
Robyn N. Taylor
Keyword(s):  
High School ◽  
Emotional Intelligence ◽  
Postsecondary Education ◽  
Life Transition ◽  
Full Time ◽  
Major Life ◽  
Long Term Stability ◽  
Time Period ◽  
Transition From High School

Abstract. The concept of emotional intelligence (EI) has attracted growing interest from researchers working in various fields. The present study examined the long-term stability (32 months) of EI-related abilities over the course of a major life transition (the transition from high school to university). During the first week of full-time study, a large group of undergraduates completed the EQ-i:Short; 32 months later a random subset of these students (N = 238), who had started their postsecondary education within 24 months of graduating from high school, completed the measures for a second time. The study found EI scores to be relatively stable over the 32-month time period. EI scores were also found to be significantly higher at Time 2; the overall pattern of change in EI-levels was more than can be attributed to the increased age of the participants.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

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