Weak Signal Detection System Based on Lock-in Amplifier Technology

2013 ◽  
Vol 389 ◽  
pp. 489-493
Author(s):  
Yong Lv ◽  
Chun Hui Niu ◽  
Yue Qiang Li ◽  
Qing Shan Chen ◽  
Xiao Ying Li ◽  
...  
Keyword(s):  
Signal Detection ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
Weak Signal ◽  
Weak Signal Detection ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Phase Sensitive ◽  
Lock In

In order to detect the weak signal deeply buried in the noise, a weak signal detection system based on lock-in amplifier is proposed. The system includes the preamplifier circuit, active low pass filter circuit, AC amplifying circuit and phase sensitive demodulation circuit. Test results show that it can greatly increase the signal-to-noise ratio (SNR) up to 12.7db.

Weak photoacoustic signal detection based on the differential duffing oscillator

2018 ◽  
Vol 32 (09) ◽  
pp. 1850103 ◽  
Author(s):  
Chenjing Li ◽  
Xuemei Xu ◽  
Yipeng Ding ◽  
Linzi Yin ◽  
Beibei Dou
Keyword(s):  
Signal Detection ◽  
Photoacoustic Spectroscopy ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
Duffing Oscillator ◽  
Threshold Value ◽  
Photoacoustic Signal ◽  
Weak Signal ◽  
Weak Signal Detection ◽  
First Time

In view of photoacoustic spectroscopy theory, the relationship between weak photoacoustic signal and gas concentration is described. The studies, on the principle of Duffing oscillator for identifying state transition as well as determining the threshold value, have proven the feasibility of applying the Duffing oscillator in weak signal detection. An improved differential Duffing oscillator is proposed to identify weak signals with any frequency and ameliorate the signal-to-noise ratio. The analytical methods and numerical experiments of the novel model are introduced in detail to confirm its superiority. Then the signal detection system of weak photoacoustic based on differential Duffing oscillator is constructed, it is the first time that the weak signal detection method with differential Duffing oscillator is applied triumphantly in photoacoustic spectroscopy gas monitoring technology.

scholarly journals A Memristor Based Chaotic Oscillator for Weak Signal Detection and Its Circuitry Realization

2021 ◽  
Author(s):  
Kaifeng Dong ◽  
Kun Xu ◽  
Youyou Zhou ◽  
Chao Zuo ◽  
Leiming Wang ◽  
...  
Keyword(s):  
Signal Detection ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
Detection Accuracy ◽  
Chaotic Oscillator ◽  
Weak Signal ◽  
Weak Signal Detection ◽  
Noise Performance ◽  
Detection Range ◽  
Implementation Scheme

Abstract A new type of weak signal detection system that combines the memristor and Van der pol-Duffing chaotic system has been proposed in this paper, and the dynamic characteristics of the system are studied. It is observed that the system can change from a chaotic state to a periodic state under different driving force amplitudes. Moreover, as compared with several classical chaotic oscillators, the numerical simulation results show that the system has stronger anti-noise performance with the detectable signal-to-noise ratio reaches -163dB, and has a wider detection range. Its detection accuracy is up to 1 × 10 −9 . More importantly, this paper provides the circuit implementation scheme of the system, and the weak signal can be detected with our designed circuit. This may offer a possible way for weak signal detection system with good performance in anti-noise performance, detection range and accuracy.

The Design of Lock-in Amplifier Based on DSP Builder

2013 ◽  
Vol 718-720 ◽  
pp. 733-738
Author(s):  
Qiang Zheng ◽  
Cheng Ma
Keyword(s):  
Background Noise ◽  
Narrow Band ◽  
Comb Filter ◽  
Weak Signal ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Dsp Builder ◽  
System Clock ◽  
Low Pass ◽  
Lock In

Lock-in amplifier is widely used to detect weak signals from significant background noise. In this paper, an FPGA-based Lock-in amplifier is implemented on the DSP Builder platform to measure impedance between biological cells and electrodes. To improve the measuring accuracy, a narrow band low pass filter with low cut off frequency was implemented. This low pass filter consists of a five-stage cascaded integrator-comb filter, two half band filters and a FIR low pass filter. Simulation shows that with a system clock of 10MHz, the cut off frequency of the low pass filter is lower than 20Hz. Experiments demonstrate that the implemented lock-in amplifier is able to detect weak signal with strong noise, making it an attractive approach to implement lock-in amplifiers which is more flexible and can meet the needs for specified measurements.

The Application of Lock-in Amplifier in Weak Signal Detection

2011 ◽  
Vol 403-408 ◽  
pp. 2650-2653 ◽  
Author(s):  
Jia Tian Zhang ◽  
Gang Liu
Keyword(s):  
Signal Detection ◽  
Input Signal ◽  
Basic Concept ◽  
Electric Signal ◽  
Band Pass Filter ◽  
Weak Signal ◽  
Weak Signal Detection ◽  
Pass Filter ◽  
Band Pass ◽  
Lock In

The paper introduces the lock-in amplifier, the basic concept of weak signal detection, and analyzes its application in weak electric signal detection.The results show that: lock-in amplifier has a very strong resistance to noise. Compared to band-pass filter, the output signal is not amplify input signal, but amplify the AC signal and turn it into DC signal.

Rapid Recovery of Wide-Bandwidth Photothermal Signals via Homodyne Photothermal Spectrometry: Theory and Methodology

1993 ◽  
Vol 47 (4) ◽  
pp. 489-500 ◽  
Author(s):  
J. F. Power ◽  
M. C. Prystay
Keyword(s):  
High Frequency ◽  
Low Cost ◽  
Signal Recovery ◽  
Wide Bandwidth ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Filter Output ◽  
Low Pass ◽  
Four Quadrant ◽  
Lock In

Homodyne photothermal spectrometry (HPS) is a very wide bandwidth signal recovery technique which uses many of the elements of lock-in detection at very low cost. The method uses a frequency sweep, with a high-frequency bandwidth of up to 10 MHz, to excite a linear photothermal system. The response sweep of the photothermal system is downshifted into a bandwidth of a few kilohertz by means of in-phase mixing with the excitation sweep with the use of a four-quadrant double-balanced mixer and a low-pass filter. Under conditions derived from theory, the filter output gives a good approximation to the real part of the photothermal system's frequency response, dispersed as a function of time. From a recording of this signal, the frequency and impulse response of the photothermal system are rapidly recovered at very high resolution. The method has been tested with the use of laser photopyroelectric effect spectrometry and provides an inexpensive, convenient method for the recovery of high-frequency photothermal signals.

scholarly journals Audio Watermarking Combined with Compressive Sampling Based on QIM and DST-QR Techniques

2019 ◽  
Vol 19 (1) ◽  
pp. 20
Author(s):  
Irma Safitri ◽  
Gelar Budiman ◽  
Arfidianti Kartika Meiza Putri
Keyword(s):  
Signal To Noise Ratio ◽  
Transformation Process ◽  
Compressive Sampling ◽  
Audio Watermarking ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Digital Copyright ◽  
Sine Transform ◽  
Low Pass ◽  
Speed Change

Abuse is not only done to copy or distribute data but also to the digital copyright labels. There is a way to protect data by inserting or hiding a piece of certain information, namely a watermarking technique. In this paper, we propose audio watermarking with Quantization Index Modulation (QIM) method as an embedding process combined with Compressive Sampling (CS), Discrete Sine Transform (DST) and QR decomposition. Binary image is used as a watermark inserted in host audio. DST is used for transformation process from time domain to frequency domain, while QR is used to decompose onedimension matrix into two-dimension matrix. Meanwhile, CS is used to obtain the compressed watermark file which is done before the embedding process. QIM method is used to embed the watermark file to the audio host file. Simulation results indicated that the proposed audio watermarking technique has good robustness against some attacks such as Low Pass Filter (LPF), resampling and linear speed change. In addition, it provides good performance in terms of imperceptibility with Signal to Noise Ratio (SNR) > 20 dB and capacity C = 689 bps.

The Human Controller as an Adaptive, Low Pass Filter

1967 ◽  
Vol 9 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Gordon H. Robinson
Keyword(s):  
Signal To Noise Ratio ◽  
Noise Signal ◽  
Manual Control ◽  
Future Research ◽  
Research Needs ◽  
Descriptive Model ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Independent Variables ◽  
Low Pass

Data is presented on the ability of a human controller to track a signal contaminated with noise. Signal frequencies and signal-to-noise ratio are the independent variables. An optimal, adaptive filter is presented for comparison. A descriptive model is derived based on known human characteristics in manual control. Future research needs are discussed.

scholarly journals A CMOS Low Pass Filter for SoC Lock-in-Based Measurement Devices

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5173 ◽  
Author(s):  
Jorge Pérez-Bailón ◽  
Belén Calvo ◽  
Nicolás Medrano
Keyword(s):  
Dynamic Range ◽  
Current Trend ◽  
Cutoff Frequency ◽  
Oxide Semiconductor ◽  
Constant Current ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Compact Size ◽  
Low Pass ◽  
Lock In

This paper presents a fully integrated Gm–C low pass filter (LPF) based on a current steering Gm reduction-tuning technique, specifically designed to operate as the output stage of a SoC lock-in amplifier. To validate this proposal, a first-order and a second-order single-ended topology were integrated into a 1.8 V to 0.18 µm CMOS (Complementary Metal-Oxide-Semiconductor) process, showing experimentally a tuneable cutoff frequency that spanned five orders of magnitude, from tens of mHz to kHz, with a constant current consumption (below 3 µA/pole), compact size (<0.0140 mm2/pole), and a dynamic range better than 70 dB. Compared to state-of-the-art solutions, the proposed approach exhibited very competitive performances while simultaneously fully satisfying the demanding requirements of on-chip portable measurement systems in terms of highly efficient area and power. This is of special relevance, taking into account the current trend towards multichannel instruments to process sensor arrays, as the total area and power consumption will be proportional to the number of channels.

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