signal amplifier
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Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 242
Almudena Marti ◽  
Jurriaan Huskens

Affinity sensing of nucleic acids is among the most investigated areas in biosensing due to the growing importance of DNA diagnostics in healthcare research and clinical applications. Here, we report a simple electrochemical DNA detection layer, based on poly-l-lysine (PLL), in combination with gold nanoparticles (AuNPs) as a signal amplifier. The layer shows excellent reduction of non-specific binding and thereby high contrast between amplified and non-amplified signals with functionalized AuNPs; the relative change in current was 10-fold compared to the non-amplified signal. The present work may provide a general method for the detection of tumor markers based on electrochemical DNA sensing.

2022 ◽  
Vol 355 ◽  
pp. 02056
Yajun Ma ◽  
Wei Xiong ◽  
Zhen Wang ◽  
Wenzhang Li ◽  
Jiajia Xu

The converter is a measuring device and is used together with the displacement sensor. In view of the existing sensor transform device is susceptible to error and temperature drift effects acquisition accuracy is not high, we design a high precision transducer, multi-sensor information fusion for vehicle steering gear shaft angular displacement signal measurement, signal transformation and digital transmission. The converter has the characteristics of high precision, miniaturization and low cost. Multi-sensor information fusion high-precision converter adopts front-end signal amplifier circuit, following filter processing circuit and embedded software of microprocessor for online compensation to satisfy the requirements of high-precision transformation. The microcontroller is used as the main control chip to meet the requirements of 8-channel bipolar analog signal acquisition. Two 14-bit, 6-channel A/D chips are used to convert the bipolar analog signal in the range of ±10V, and the RS422 hardware interface circuit performs digital transmission according to the time sequence specified by the central programmer. The experimental results show that the conversion accuracy of the device can reach 0.06%, the digital signal transmission is stable, and it can be widely used in industrial production.

Electronics ◽  
2021 ◽  
Vol 10 (21) ◽  
pp. 2631
Eduardo Alonso Rivas ◽  
Graziella Scandurra ◽  
Carmine Ciofi ◽  
Carlos Rodríguez-Morcillo García  ◽  
Romano Giannetti

The most common method used to pick up biomedical signals is through metallic electrodes coupled to the input of high-gain, low-noise amplifiers. Unfortunately, electrodes, amongst other effects, introduce an undesired contact resistance and a contact potential. The contact potential needs to be rejected since it would otherwise cause the saturation of the input stage of the amplifiers, and this is almost always obtained by inserting a simple RC high-pass filter in the input signal path. The contact resistance needs to be estimated to ensure that it does not impair correct measurements. Methods exist for estimating the contact resistance by dynamically modifying the input network configuration, but because of the presence of the input RC filter, long transients are induced any time a switch occurs between different input configurations, so that the measurement time may become unacceptably long. In this paper, we propose a new topology for a DC removal network at the input of the differential signal amplifier that results in an AC filter whose time constant can be continuously changed by means of a control voltage. As such, we can speed up the recovery from transients by setting very short time constants (during the input resistance estimation process) while maintaining the ability to obtain very low cut-in frequencies by setting a much larger time constant during actual measurements. A prototype of the system was built and tested in order to demonstrate the advantage of the approach we propose in terms of reduced measurement time.

2021 ◽  
pp. 132665
Qi Wang ◽  
Xueting Tang ◽  
Ruwen Lv ◽  
Kaiyuan Tan ◽  
Zinan Zhao ◽  

2021 ◽  
pp. 1-16
Sachchida Nand Shukla ◽  
Geetika Srivastava ◽  
Syed Shamroz Arshad

2021 ◽  
Vol 5 (4) ◽  
pp. 760-767
Rufman Akbar ◽  
Chaerul Anwar ◽  
Johannes Hamonangan Siregar

Situation during COVID19 pandemic, requires all schools to conduct online learning. This condition is done to prevent the spread of pandemic. The problem is that the infrastructure is not fully supported. Learning in marginal areas is still constrained by the difficulty of the signal or internet connection. This research was conducted to obtain an infrastructure design that can be used in areas with minimal internet connection, or even no internet network connection. Using R&D, the research begins by designing a network device on the school side – Acces Point, also a tool to expand coverage -  repeater. Furthermore, design and testing of signal amplifier antennas that can be used on the client side is carried out. For the client side, several types of amplifier antennas are made that can be used to receive Wifi frequencies. There are three types of antennas that are made and tested, namely Yagi, Yagi Cross, and cantennas. Both are Unidirectional antenna. Connection quality is measured with a Wifi analyzer device to determine network quality. As for mobile phones, it is measured using the Wifi Master Key. The result obtained is a WELAN infrastructure design which is equipped with unidirectional antenna design with a total range of 8 Km.  

2021 ◽  
Vol 15 ◽  
Larry E. Shupe ◽  
Frank P. Miles ◽  
Geoff Jones ◽  
Richy Yun ◽  
Jonathan Mishler ◽  

Toward addressing many neuroprosthetic applications, the Neurochip3 (NC3) is a multichannel bidirectional brain-computer interface that operates autonomously and can support closed-loop activity-dependent stimulation. It consists of four circuit boards populated with off-the-shelf components and is sufficiently compact to be carried on the head of a non-human primate (NHP). NC3 has six main components: (1) an analog front-end with an Intan biophysical signal amplifier (16 differential or 32 single-ended channels) and a 3-axis accelerometer, (2) a digital control system comprised of a Cyclone V FPGA and Atmel SAM4 MCU, (3) a micro SD Card for 128 GB or more storage, (4) a 6-channel differential stimulator with ±60 V compliance, (5) a rechargeable battery pack supporting autonomous operation for up to 24 h and, (6) infrared transceiver and serial ports for communication. The NC3 and earlier versions have been successfully deployed in many closed-loop operations to induce synaptic plasticity and bridge lost biological connections, as well as deliver activity-dependent intracranial reinforcement. These paradigms to strengthen or replace impaired connections have many applications in neuroprosthetics and neurorehabilitation.

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