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In this paper, we present the design and implementation of an RF bandpass ΣΔ modulator where the loop filter is a 4th order capacitively-coupled LC filter. A design methodology using coupling capacitor and the feedback Finite Impulse Response Digital-to-Analog Converter (FIRDAC) coefficients in order to obtain the desired Noise Transfer Function (NTF) is presented. The proposed capacitively-coupled...
The design of a fully integrated multi-standard UHF receiver front-end to be embedded in environmental data collection satellites is proposed. The circuit operates under the requirements of both SBCDA and the ARGOS 3. For that, the specifications of a multi-standard receiver front-end are firstly derived and then the implementation of a 70.4dB voltage gain, 2.3dB NF, 48mW energy consumption, single-ended...
In this paper is presented the procedure to wind speed measurement based on ultrasonic sensors. For this purpose the ultrasonic Time-of-Flight (ToF) was estimated using the DFT (Discrete Fourier Transform) technique. The analysis of the influence of multiplicative and additive noise of the medium into the DFT is carried out. Then, the uncertainties propagation for ToF and wind speed measurements is...
This paper presents the procedures for the wind speed measurement using ultrasonic transducers. The wind speed measurement is based on the time-of-flight (ToF) ultrasonic estimation that has been estimated using the Extended Kalman Filter (EKF) algorithm. For this purpose it was developed the dynamic system model in state space and was analyzed the convergence of the EKF algorithm. Simulation results...
A method for measuring speed wind, based on echo detection using ultrasonic transducers with stationary wavelet transform is presented. The stationary wavelet transform (SWT) can be obtained by modifying the basic scheme of discrete wavelet transform (DWT). Two filters are applied to produce the output two sequences at each level. Since decimation is not obtained at the exit of each level, sequences...
This paper presents an architecture of a hot-wire anemometer that adjusts the difference between the sensor temperature and the fluid temperature and maximizes the sensitivity of the output quantity (voltage or pulse width) in relation to the input quantity (velocity). Analyses were made for the PTC and NTC sensors type and for output in pulse width or analog voltage type. It was verified that, for...
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