A Remote Sensing Scheme for Fault Diagnosis to Wind Turbines: An Academic Experimental Set-Up

Nowadays, remote sensing for structural fault examination to wind turbines is an important technological challenger. On the other hand, laser diodes represent a low-cost option to implement a remote vibrometer sensor by just using cheap analog electronics. Therefore, a recent electronic circuit along with a laser diode is conceived to detect faults on a winding structure due to vibrations mainly induced by the wind and its rotary parts with possible mechanical defects. The electronic parts consist of a sequence of bandpass filters and peak detector stages. Besides, an academic experimental platform is constructed to validate the performance of the proposed remote sensing scheme for fault diagnosis in wind turbine structures.

CMOS Analog AGC for Biomedical Applications

In this paper, we present the design of an analog Automatic Gain Control with a small silicon area and reduced power consumption using a 0.5 μ m process. The design uses a classical approach implementing the AGC system with simple blocks, such as: peak detector, difference amplifier, four-quadrant multiplier, and inversor amplifier. Those blocks were realized by using a modified Miller type OPAMP, which allows indirect compensation, while the peak detector uses a MOS diode. The AGC design is simulated using the Tanner-Eda environment and Berkeley models BSIM49 of the On-Semiconductor C5 process, and it was fabricated through the MOSIS prototyping service. The AGC system has an operation frequency of around 1 kHz, covering the range of biomedical applications, power consumption of 200 μ W, and the design occupies a silicon area of approximately 508.8 μ m × 317.7 μ m. According to the characteristics obtained at the experimental level (attack and release time), this AGC can be applied to hearing aid systems.

A 2.4 GHz 2.9 mW Zigbee RF Receiver with Current-Reusing and Function-Reused Mixing Techniques

This study presents a low-power Zigbee receiver with a current-reusing structure and function-reused mixing techniques. To reduce the overall power consumption, a low noise amplifier (LNA) and a power amplifier (PA) share the biasing current with a voltage-controlled oscillator (VCO) in the receiving (RX) mode and transmitting (TX) mode, respectively. The function-reused mixer reuses the radio frequency trans-conductance (RF gm) stage to amplify the down-converted intermediate frequency (IF) signal, obtaining a free IF gain without extra power consumption. A peak detector circuit detects the receiving signal strength and auto-adjusts the biasing current to save power when a strong signal strength is detected. Meanwhile, the peak detector helps to provide a coarse gain control as part of the auto-gain-control function. As part of the IF gain range is shared by the multiple-feedback (MFB) low-pass filter, the number of programmable-gain IF amplifier stages can be reduced, which also means a decrease in power consumption. A prototype of this wireless sensor network (WSN) receiver was designed and fabricated using the TSMC 130 nm CMOS process under a supply voltage of 1 V. The entire receiver realizes a noise figure (NF) of 3.5 dB and a receiving sensitivity of −90 dBm for the 0.25 Mbps offset quadrature phase shift keying (O-QPSK) signal with a power consumption of 2.9 mW.