Papers by Keyword: Amplifier

Abstract: Prolonged 500 °C to 700 °C electrical testing data from 4H-SiC junction field effect transistor (JFET) integrated circuits (ICs) are combined with post-testing microscopic studies in order to gain more comprehensive understanding of the durability limits of the present version of NASA Glenn's extreme temperature microelectronics technology. The results of this study support the hypothesis that T ≥ 500 °C durability-limiting IC failure initiates with thermal stress-related crack formation where dielectric passivation layers overcoat micron-scale vertical features including patterned metal traces.

Abstract: The article presents the results of unpublished research on the new generation current sensors, designed on the basis of cold-cast magnetic materials. The development of current sensors with core cast focused primarily on the possibility of their application for the measurement of large currents and for the purpose of measuring the electricity and power electronics. The article presents the results of measurements of transmission characteristics of the prototype sensor, the sensing ampli­fier design and measurement results of the entire scanning unit.

Abstract: This paper presents a high unity gain bandwidth fully differential folded-cascode operational amplifier using gain-boosted technique. The amplifier is designed in TSMC 0.18μm 1P6M CMOS technology. The unity-gain bandwidth (GBW) and poles of the gain-boosting amplifiers were carefully designed to improve the stability. The implemented design provides a direct current (DC) gain of around 93 dB with a unity gain frequency of 1.8GHz. It exhibits a DC gain larger than 88dB when the output common-mode voltage between 0.6 V and 1.2V. the overall layout size is 96μm×120μm.

Abstract: The hydroacoustic transponder based on the principle of laser interferometry is investigated, which consists of three parts: 1) the front-end module, which is a signal receiving and pre-processing module, and consists of a laser interferometric receiver and a filter group; 2) the signal processing module, which consists of the data acquisition module and a data processing system; 3) the back-pulse module, which consists of an automatic gain adjustment module, a transmitter module and a back-transducer. We give the detailed designing flow charts of the hardware and software programs.

Abstract: High-frequency electronic circuit is an important basic specialized course for the major of electronic information engineering, communication engineering, and electronic science and technology. Combined with a dozen years of classroom teaching experience and started from several aspects like relevancy of front-back courses, teaching framework and theoretical teaching content, this paper will discuss analogy teaching method of related content about signal amplifier, mixing, modulation and demodulation in order to help students to understand chapter structure. In the process of teaching, we should pay more attention to students ' weaknesses of knowledge, then stimulate their interests in learning and improve the teaching effectively quality.

Abstract: Bandgap voltage reference, to provide a temperature and power supply insensitive output voltage, is a very important module in the analog integrated circuits and mixed-signal integrated circuits. In this paper, a high performance CMOS bandgap with low-power consumption has been designed. It can get the PTAT (Proportional to absolute temperature) current, and then get the reference voltage. Based on 0.35μm CMOS process, using HSPICE 2008 software for circuit simulation, the results showed that , when the temperature changes from -40 to 80 °C, the proposed circuit’s reference voltage achieve to 1.2V, temperature coefficient is 3.09ppm/°C. Adopt a series of measures, like ESD protection circuit, in layout design. The ultimately design through the DRC and LVS verification, and the final layout size is 700μm * 560μm.

Abstract: An array which possess more array element number and whose frequency of the drive signal can be as large as possible in a range, directivity will be more preferable. On the other hand, when the structure of the sound radiating surface of the transducer or array layout is symmetrical, the corresponding directivity pattern will be symmetrical. In order to test transducer directivity, two methods are designed. The one is to measure the ultrasonic sound pressure level by instruments. The sound pressure level is measured at multiple points to deduce the directivity angle of the acoustic transducer array. The beam width of the 3×3 array is about at 23kHz, and the directivity acute angle is about 10°; higher frequencies will lead to the side lobes, but it can be negligible when compared to the main lobe. The other method is using the frequency analyzer to test transducer directivity in a silencer chamber. The sound pressure level can be read out from frequency response diagrams. The angle between the sound pressure value that decreasing 3db from the max value 111.7db and the max value is about 11°. So the directivity acute angle is about 11°. It should be noticed that, as the directivity diagram can not be directly attributed, there is some deviation in the conclusion.

Abstract: Magnetic sensors offer many essential benefits: they enable contactless and thus without wear measurement of mechanical amounts of such as the rotation angle and angular velocity. And are a powerful and economical solution. In this work became a successful attempt to detect and record the noise of a Anisotropic Magnetoresistors (AMR) sensor, hte HMC2003, which manufactured by Honeywell Inc. was tested for its ability to detect the magnetic field and as well as how the corruption, which are involved due to the noise.

Abstract: High-performance filter is the key to improving the detection accuracy of geophysical instruments. In order to achieve high-precision measurement of small signals, this paper presents a design of high-performance programmable filter based on TLC7528. The system design mainly included programmable amplifier circuit design, programmable filter circuit design, amplitude-frequency test circuit design, display circuit and the keyboard circuit design. The system used a microcontroller as the control center for system parameters setting and control, adopted analog switches and selected low-noise op amp to achieve programmable gain control, used TLC7528 to realize the filter cut off frequency adjustable by changing its internal resistance value and used the DDS chip and RMS conversion chip to design the circuit of amplitude-frequency characteristics, so as to test and analysis the signal amplitude and frequency of the system design filter. The experimental test data showed that the high performance filter has the characteristics of good linear, small voltage gain error, low power, flexibility and little environmental impact. It can significantly improve the accuracy of the geophysical detection equipment.

Abstract: In the electronic measurement field, how to measure the open-loop amplitude frequency characteristics of the amplifier automatically is a question to be overcame. And now , the system ,which under the integrated development environment that the virtual instrument software LabVIEW provides, to measure the open-loop amplitude frequency characteristics of the amplifier is developed by combining the modern electronic measurement technology and computer data processing technology. The virtual signal generator which is based on the data acquisition card, signal acquisition, correlation analysis, frequency response analysis, etc is included in the system. This design mainly includes the hardware circuit and the software program. The hardware circuit consists of the low noise preamplifier, measured operational amplifier, data acquisition card, power supply, computer, etc. Modular design is adopted in the software part, which includes the design of soft panel, signal generation, collection and analysis module. The advantages of the virtual instrument, such as the digital signal processing, waveform data automatic storage, graphical programming, are fully used in the modern electronic measurement. Simple structure, low cost, high level of test automation are its characteristics.