波長(zhǎng)信號(hào)的解調(diào)是實(shí)現(xiàn)光纖光柵傳感網(wǎng)絡(luò)的關(guān)鍵，基于現(xiàn)有的光纖光柵傳感器解調(diào)方法，提出一種基于FPGA的雙匹配光纖光柵解調(diào)方法，此系統(tǒng)是一種高速率、高精度、低成本的解調(diào)系統(tǒng)，并且通過引入雙匹配光柵有效地克服了雙值問題同時(shí)擴(kuò)大了檢測(cè)范圍。分析了光纖光柵的測(cè)溫原理并給出了該方案軟硬件設(shè)計(jì)，綜合考慮系統(tǒng)的解調(diào)精度和FPGA的處理速度給出了基于拉格朗日的曲線擬合算法。
Abstract:
Sensor is one of the most important application of the fiber grating. Wavelength signal demodulating is the key techniques to carry out fiber grating sensing network， based on several existing methods of fiber grating sensor demodulation inadequate， a two-match fiber grating demodulation method was presented. This system is a high-speed， high precision， low-cost demodulation system. And by introducing a two-match grating effectively overcomes the problem of double value while expands the scope of testing. This paper analyzes the principle of fiber Bragg grating TemperATure and gives the software and hardware design of the program. Considering the system of demodulation accuracy and processing speed of FPGA，this paper gives the curve fitting algorithm based on Lagrange.
Integrated EMI/Thermal Design forSwitching Power SuppliesWei ZhangThesis submitted to the Faculty of theVirginia Polytechnic Institute and State Universityin partial fulfillment of the requirements for the degree of
Integrated EMI/Thermal Design forSwitching Power SuppliesWei Zhang(ABSTRACT)This work presents the modeling and analysis of EMI and thermal performancefor switch power supply by using the CAD tools. The methodology and design guidelinesare developed.By using a boost PFC circuit as an example, an equivalent circuit model is builtfor EMI noise prediction and analysis. The parasitic elements of circuit layout andcomponents are extracted analytically or by using CAD tools. Based on the model, circuitlayout and magnetic component design are modified to minimize circuit EMI. EMI filtercan be designed at an early stage without prototype implementation.In the second part, thermal analyses are conducted for the circuit by using thesoftware Flotherm, which includes the mechanism of conduction, convection andradiation. Thermal models are built for the components. Thermal performance of thecircuit and the TemperATure profile of components are predicted. Improved thermalmanagement and winding arrangement are investigated to reduce TemperATure.In the third part, several circuit layouts and inductor design examples are checkedfrom both the EMI and thermal point of view. Insightful information is obtained.
Abstract: Many modern industrial, medical, and commercial applications require TemperATure measurements in the extended TemperATure rangewith accuracies of ±0.3°C or better, performed with reasonable cost and often with low power consumption. This article explains how platinumresistance TemperATure detectors (PRTDs) can perform measurements over wide TemperATure ranges of -200°C to +850°C, with absolute accuracyand repeatability better than ±0.3°C, when used with modern processors capable of resolving nonlinear mathematical equation quickly and costeffectively. This article is the second installment of a series on PRTDs. For the first installment, please read application note 4875, "High-Accuracy TemperATure Measurements Call for Platinum Resistance TemperATure Detectors (PRTDs) and Precision Delta-Sigma ADCs."
Logger iButton devices have gained a lot of popularity with researchers. Although free evaluation software is easy to use and welldocumented, the choices and inputs that need to be made can sometimes be challenging. This application note explains technicalterms that are common with TemperATure logger iButtons and how they relate to each other. Additionally, it presents an algorithm tohelp users choose the necessary input parameters, including the sample rate based on a user's needs and the available memory tostore the data.
Frequently, voltage reference stability and noise defi nemeasurement limits in instrumentation systems. In particular,reference noise often sets stable resolution limits.Reference voltages have decreased with the continuingdrop in system power supply voltages, making referencenoise increasingly important. The compressed signalprocessing range mandates a commensurate reductionin reference noise to maintain resolution. Noise ultimatelytranslates into quantization uncertainty in A to D converters,introducing jitter in applications such as scales, inertialnavigation systems, infrared thermography, DVMs andmedical imaging apparatus. A new low voltage reference,the LTC6655, has only 0.3ppm (775nV) noise at 2.5VOUT.Figure 1 lists salient specifi cations in tabular form. Accuracyand TemperATure coeffi cient are characteristic ofhigh grade, low voltage references. 0.1Hz to 10Hz noise,particularly noteworthy, is unequalled by any low voltageelectronic reference.
Digital Thermostat with High Accuracy
-6,00 to 46,00 °C
Digital Thermostat
We build a digital thermostat for home applications, which controls the room TemperATure. I
used the AT90S2313 microprocessor of ATMEL. The digital thermostat opens the main heating valve of
the apartment and the hot water flows in the radiators.
Digital Thermostat Board
This program demonstrates operation of ADC0 in polled mode. The ADC0 is
// configured to use writes to AD0BUSY as its start of conversion source and
// to measure the output of the on-chip TemperATure sensor. The TemperATure
// sensor output is converted to degrees Celsius and is transmitted out UART0
This program demonstrates operation of ADC0 in polled mode. The ADC0 is
// configured to use writes to AD0BUSY as its start of conversion source and
// to measure the output of the on-chip TemperATure sensor. The TemperATure
// sensor output is converted to degrees Celsius and is transmitted out UART0
