scholarly journals Design of an Indigenised Electronic Lock-In Amplifier

2000 ◽  
Vol 23 (1) ◽  
pp. 53-60
Author(s):  
Umesh Kumar
Keyword(s):  
Narrow Band ◽  
Signal To Noise Ratio ◽  
Broad Band ◽  
Power Line ◽  
Frequency Drift ◽  
Noise Power ◽  
Signal To Noise ◽  
Band Noise ◽  
Noise Ratio ◽  
Lock In

An indigenised lock-in amplifier is designed that enables the accurate measurement of signals contaminated by broad-band noise, power-line pick-up, frequency drift, or other sources of interference. It does this by means of an extremely narrow band detector which has the centre of its passband locked to the frequency of the signal to be measured. Large improvements in signal-to-noise ratio are achieved.

scholarly journals Performance analysis of dual-media cooperative communication based on wireless and power line under hybrid fading

2019 ◽  
Vol 15 (5) ◽  
pp. 155014771985070
Author(s):  
Zhixiong Chen ◽  
Yifang Jing ◽  
Dongsheng Han ◽  
Lijiao Wang
Keyword(s):  
Cooperative Communication ◽  
Lognormal Distribution ◽  
Signal To Noise Ratio ◽  
Power Line ◽  
Maximal Ratio Combining ◽  
Total Output ◽  
Theoretical Formula ◽  
Signal To Noise ◽  
Generation Function ◽  
Noise Ratio

Wireless communication and power line communication are extensively applied in various fields, such as household Internet of things. For cooperative communication of amplify–forward relay using wireless access and power line transmission, the hybrid model of universal Nakagami wireless fading and lognormal power line fading was used in this study. A comparative analysis of similarities between Gamma and lognormal distributions and lognormal distribution characteristics of relay link signal-to-noise ratio was also carried out. Given the deficiencies of lognormal variable add approximation method, lognormal distribution parameters combined computing method based on moment generation function was proposed. Theoretical formulas of outage probability and bit error rate after amplify–forward relay and maximal-ratio combining was derived on the basis of moment generation function of the total output signal-to-noise ratio of the system. Effectiveness and reliability of the algorithm and theoretical formula were verified through simulation, and influence rules of hybrid channel fading and power distribution on the system performance were analyzed.

The Noise Analysis of Fluid Systemsin Solid-State Nanopore Sensors

2013 ◽  
Vol 419 ◽  
pp. 517-520 ◽  
Author(s):  
Song Ying ◽  
Lei Wang ◽  
Wen Yuan Zhao
Keyword(s):  
Solid State ◽  
Signal To Noise Ratio ◽  
Noise Analysis ◽  
Power Spectra ◽  
Noise Power ◽  
Label Free ◽  
Signal To Noise ◽  
Fluid Systems ◽  
Noise Ratio ◽  
Nanopore Sensors

The solid-state nanopore sensor offers a versatile platform for the rapid, label-free electrical detection and analysis of single molecules, especially on DNA sequencing. However, the overall signal-to-noise ratio (SNA) is a major challenge in sequencing applications. In our work, two different fluid systems made by metal and plexiglass have been designed to improve the signal to noise ratio of the solid-state nanopore sensor. From the measurements on the noise power spectra with a variety of conditions, it is found that plexiglass fluid system coupled with shielding box produces a good quality of electric signals on nanopore sensors.

Effect of Modulation Source Properties upon Signal-To-Noise Ratios of Inelastic Electron Tunneling Spectra

1986 ◽  
Vol 40 (8) ◽  
pp. 1180-1183 ◽  
Author(s):  
F. A. Dethomas ◽  
Cecil Dybowski ◽  
Harvey S. Gold
Keyword(s):  
Electron Tunneling ◽  
Second Harmonic ◽  
Signal To Noise Ratio ◽  
Harmonic Distortion ◽  
Inelastic Electron ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Inelastic Electron Tunneling ◽  
Electron Tunneling Spectroscopy ◽  
Lock In

Lock-in amplification using ac modulation and second-harmonic detection is routinely employed in such techniques as ac polarography, ac voltammetry, and inelastic electron tunneling spectroscopy (IETS). Properties of the modulation source are shown in the present IET studies to limit the obtainable signal-to-noise ratio of a spectrum. A single inelastic electron tunneling junction is used to demonstrate the effect of various commercial modulation sources on the IET spectrum of benzoic acid on alumina. With all other parameters being held constant, the signal-to-noise ratio of the IET spectrum is found to be inversely correlated with the total harmonic distortion of the modulation source.

scholarly journals Coherent Power Measurements with a Compact Airborne Ka-Band Precipitation Radar

2018 ◽  
Vol 35 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Andrew L. Pazmany ◽  
Samuel J. Haimov
Keyword(s):  
Signal To Noise Ratio ◽  
Power Estimation ◽  
Noise Power ◽  
Signal Power ◽  
Signal To Noise ◽  
Precipitation Radar ◽  
Noise Component ◽  
Ka Band ◽  
Noise Ratio ◽  
Conventional Signal

AbstractCoherent power is an alternative to the conventional noise-subtracted power technique for measuring weather radar signal power. The inherent noise-canceling feature of coherent power eliminates the need for estimating and subtracting the noise component, which is required when performing conventional signal power estimation at low signal-to-noise ratio. The coherent power technique is particularly useful when averaging a high number of samples to improve sensitivity to weak signals. In such cases, the signal power is small compared to the noise power and the required accuracy of the estimated noise power may be difficult to achieve. This paper compares conventional signal power estimation with the coherent power measurement technique by investigating bias, standard deviation, and probability of false alarm and detection rates as a function of signal-to-noise ratio and threshold level. This comparison is performed using analytical expressions, numerical simulations, and analysis of cloud and precipitation data collected with the airborne solid-state Ka-band precipitation radar (KPR) operated by the University of Wyoming.

scholarly journals Improving the Signal to Noise Ratio of QTF Preamplifiers Dedicated for QEPAS Applications

2020 ◽  
Vol 10 (12) ◽  
pp. 4105
Author(s):  
Piotr Z. Wieczorek ◽  
Tomasz Starecki ◽  
Frank K. Tittel
Keyword(s):  
Operational Amplifier ◽  
Narrow Band ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Electrical Signal ◽  
Low Noise ◽  
Detection Sensitivity ◽  
Noise Amplitude ◽  
Signal To Noise ◽  
Noise Ratio

The signal-to-noise ratio (SNR) is a major factor that limits the detection sensitivity of quartz-enhanced photoacoustic spectroscopy (QEPAS) sensors. The higher the electrical signal level compared to the noise amplitude is the lower the concentration of gases that can be detected. For this reason the preamplifier circuits used in QEPAS should be optimized for low-frequency narrow-band applications. Moreover, special care should be taken when choosing a particular operational amplifier in either a transimpedance or voltage (differential) configuration. It turns out that depending on the preamp topology different operational amplifier parameters should be carefully considered when a high SNR of the whole QEPAS system is required. In this article we analyzed the influence of the crucial parameters of low-noise operational preamplifiers used in QEPAS applications and show the resulting limitations of transimpedance and voltage configurations.

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