scholarly journals A Second-Generation Voltage-Conveyor-Based Interface for Ultrasonic PVDF Sensors

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 99
Author(s):  
Salvatore A. Pullano ◽  
Antonino S. Fiorillo ◽  
Gianluca Barile ◽  
Vincenzo Stornelli ◽  
Giuseppe Ferri

Exploiting the transmission and reception of low frequency ultrasounds in air is often associated with the innate echolocating abilities of some mammals, later emulated with sophisticated electronic systems, to obtain information about unstructured environments. Here, we present a novel approach for the reception of ultrasounds in air, which exploits a piezopolymer broadband sensor and an electronic interface based on a second-generation voltage conveyor (VCII). Taking advantage of its capability to manipulate both voltage and current signals, in this paper, we propose an extremely simple interface that presents a sensitivity level of about −100 dB, which is in line with commercially available references. The presented results are obtained without any filtration stage. The second-generation voltage conveyor active device is implemented through a commercially available AD844, with a supply voltage of ±15 V.

2020 ◽  
Vol 10 (6) ◽  
pp. 902-908
Author(s):  
Syed Zahiruddin ◽  
Avireni Srinivasulu ◽  
Musala Sarada

Objective: The interest concern towards the development of enabling technology towards new current mode devices has forced the designers and researchers for the invention of devices, which has having the characteristics like such as low power, robustness, compactness, efficiency and scalability. Methods: Second Generation Current Controlled Conveyor (CCCII) is the prevailing current mode device of the times today. Since its invention by A. Fabre, it has prominent applications in the field of analog signal processing and in biomedical applications too. In this manuscript, CCCII is used as an enabling device to design a Frequency Shift Keying (FSK) Generator. Results: The proposed topology is designed using a single active device CCCII with least passive components. The circuit enjoys the features of like electronic tunability of frequency using the bias current. Conclusion: It can be concluded that the FSK generator circuit designed using single CCCII confers better results in contrast to the existing structures. The maximum power consumption is 0.196 mW. The proposed circuit has the benefit of simple configuration, which is very much proficient for IC fabrication.


Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2931
Author(s):  
Waldemar Jendernalik ◽  
Jacek Jakusz ◽  
Grzegorz Blakiewicz

Buffer-based CMOS filters are maximally simplified circuits containing as few transistors as possible. Their applications, among others, include nano to micro watt biomedical sensors that process physiological signals of frequencies from 0.01 Hz to about 3 kHz. The order of a buffer-based filter is not greater than two. Hence, to obtain higher-order filters, a cascade of second-order filters is constructed. In this paper, a more general method for buffer-based filter synthesis is developed and presented. The method uses RLC ladder prototypes to obtain filters of arbitrary orders. In addition, a set of novel circuit solutions with ultra-low voltage and power are proposed. The introduced circuits were synthesized and simulated using 180-nm CMOS technology of X-FAB. One of the designed circuits is a fourth-order, low-pass filter that features: 100-Hz passband, 0.4-V supply voltage, power consumption of less than 5 nW, and dynamic range above 60 dB. Moreover, the total capacitance of the proposed filter (31 pF) is 25% lower compared to the structure synthesized using a conventional cascade method (40 pF).


The technology has grown at an ultra-fast pace along with the world. Small devices with less power and high efficiency are in demand. As the circuit size gets smaller, the power requirement increases due to a greater number of transistors. A pre-scaler is a circuit which reduces the high frequency signal to a low frequency signal by integer division. A new approach to low power pre-scaler is proposed in this paper, which is an add-on to the conventional pre-scaler circuit. A true single-phase clock (TSPC) circuit reduces the skew problems in the clock and is used to realize latches and flip-flops. The objective of low power is fulfilled by incorporating the Adaptive Voltage Level Source (AVLS) to TSPC based circuit. The proposed AVLS-TSPC based pre-scaler was analyzed for a frequency of 10 MHz with a supply voltage of 1.8 V for both divide by 2 and 3 modes. The proposed pre-scaler consumes considerably lesser power when compared to that of the existing pre-scaler circuit. The circuits are implemented in 180 nm CMOS technology using Cadence Virtuoso and simulated using Cadence Spectre.


2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Kun Zhang ◽  
Minrui Fei ◽  
Xin Li ◽  
Huiyu Zhou

Features analysis is an important task which can significantly affect the performance of automatic bacteria colony picking. Unstructured environments also affect the automatic colony screening. This paper presents a novel approach for adaptive colony segmentation in unstructured environments by treating the detected peaks of intensity histograms as a morphological feature of images. In order to avoid disturbing peaks, an entropy based mean shift filter is introduced to smooth images as a preprocessing step. The relevance and importance of these features can be determined in an improved support vector machine classifier using unascertained least square estimation. Experimental results show that the proposed unascertained least square support vector machine (ULSSVM) has better recognition accuracy than the other state-of-the-art techniques, and its training process takes less time than most of the traditional approaches presented in this paper.


Author(s):  
S.A.M. Bou Jawde ◽  
A. Majumdar ◽  
A.J. Walkey ◽  
G.T. O'Connor ◽  
B.J. Smith ◽  
...  

2020 ◽  
Vol 12 (11) ◽  
pp. 1870 ◽  
Author(s):  
Qingqing Li ◽  
Paavo Nevalainen ◽  
Jorge Peña Queralta ◽  
Jukka Heikkonen ◽  
Tomi Westerlund

Autonomous harvesting and transportation is a long-term goal of the forest industry. One of the main challenges is the accurate localization of both vehicles and trees in a forest. Forests are unstructured environments where it is difficult to find a group of significant landmarks for current fast feature-based place recognition algorithms. This paper proposes a novel approach where local point clouds are matched to a global tree map using the Delaunay triangularization as the representation format. Instead of point cloud based matching methods, we utilize a topology-based method. First, tree trunk positions are registered at a prior run done by a forest harvester. Second, the resulting map is Delaunay triangularized. Third, a local submap of the autonomous robot is registered, triangularized and matched using triangular similarity maximization to estimate the position of the robot. We test our method on a dataset accumulated from a forestry site at Lieksa, Finland. A total length of 200 m of harvester path was recorded by an industrial harvester with a 3D laser scanner and a geolocation unit fixed to the frame. Our experiments show a 12 cm s.t.d. in the location accuracy and with real-time data processing for speeds not exceeding 0.5 m/s. The accuracy and speed limit are realistic during forest operations.


Author(s):  
Jianwei Du ◽  
Zhengguang Xu ◽  
Zhichun Mu ◽  
Yuan Yan Tang ◽  
Limin Cui ◽  
...  

This paper proposes the fractal features for glycyrrhiza fingerprint of medicinal herbs, to obtain the intrinsic mode functions (IMFs) from high to low frequency by using empirical mode decomposition (EMD). The EMD fractal features are extracted through computing the fractal dimensions of each IMF. The novel approach is applied to the recognition of the three types of glycyrrhiza fingerprints. Experiments show that EMD fractal features have better recognition rate than that of the traditional ones in the case of concentration-change, i.e. the number of peak and peak drift of sample which has slight changes. An existing method to extract the fractal features for fingerprint of medicinal herbs based on wavelet transform, which is called fractal-wavelet features, was presented. This method has anti-jamming property against the change of samples concentration. However, the recognition rate based on fractal-wavelet features is not satisfactory when fingerprint of medicinal herbs has some slight concentrations changes, the number of peak and peak drift of samples are processed in the special situation.


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