Design and development of a smart panel with five decentralised control units for the reduction of vibration and sound radiation

This Technical Report discusses the design and the construction of a smart panel with five decentralised direct velocity feedback control units in order to reduce the vibration of the panel dominated by well separated low frequency resonances. Each control unit consists of an accelerometer sensor and a piezoelectric patch strain actuator. The integrated accelerometer signal is fed back to the actuator via a fixed negative control gain. In this way the actuator generates a control excitation proportional and opposite to the measured transverse velocity of the panel so that it produces active damping on the panel. First the open loop frequency response function between the sensor and the actuator of a single channel has been studied and an analogue controller has been designed and tested in order to improve the stability of this control system. Following the stability of all five control units has been assessed using the generalised Nyquist criterion. Finally the performances of the smart panel have been tested with reference to the reduction of the vibrations at the error positions and with reference to the reduction of the radiated sound. Finally in appendix to this Report, a parametric study is presented on the properties of sensor-actuator FRFs measured with different types of piezoelectric patch actuators. The results of this parametric study have been used in order to choose the actuators to be used for the construction of the smart pane

Cascaded transformerless DC-DC voltage amplifier with optically isolated switching devices

A very high voltage amplifier is provided in which plural cascaded banks of capacitors are switched by optically isolated control switches so as to be charged in parallel from the preceding stage or capacitor bank and to discharge in series to the succeeding stage or capacitor bank in alternating control cycles. The optically isolated control switches are controlled by a logic controller whose power supply is virtually immune to interference from the very high voltage output of the amplifier by the optical isolation provided by the switches, so that a very high voltage amplification ratio may be attained using many capacitor banks in cascade

A wideband noise-canceling CMOS LNA exploiting a transformer

A broadband LNA incorporating single-ended to differential conversion, has been successfully implemented using a noise-canceling technique and a single on-chip transformer. The LNA achieves a high voltage gain of 19dB, a wideband input match (2.5-4.0 GHz), and a noise figure of 4-5.4 dB, while consuming only 8mW. The LNA is implemented in a 90nm CMOS process with 6 metal layers

Voltage amplifier for Electrical field generation

Tato bakalářská práce se zabývá návrhem a praktickou realizací napěťového zesilovače pro generování elektrického pole definovaného průběhu. V první části je uveden návrh funkčního generátoru a stejnosměrného symetrického napájecího zdroje. Ve druhé části je uveden návrh a simulace výkonového zesilovače ve třídě A a vysokonapěťového stejnosměrného zdroje. Poslední část tvoří měření na funkčním generátoru, výkonovém zesilovači a vysokonapěťovém zdroji.This bachelor’s thesis is about design and practical realization of the voltage amplifier for generating an electric field defined trace. First part is introduced design of function generator and a DC power supply symmetric. In the second part is the design and simulation of power amplifier in class A and high voltage DC source. The last part is consists of measurements on a function generator, power amplifier and high voltage DC source.

Use of both linear and logarithmic transfer functions to increase dynamic range of visual channel

Using both linear and logarithmic transfer functions in the visual channels of a dual channel radiometer increases the dynamic range to better than 1 to 10,000 foot-lamberts