Abstract:
【課題】超音波波形のエンベロープを安定化する。 【解決手段】サンプリング周期毎に任意のステップ値でカウントアップされ所定値を超えると所定値の超過分の数値となるカウンタ値A n (n=1,2,…)、を順次出力するカウンタ11と、カウンタ11から順次出力されるカウンタ値A n を閾値Thrと順次比較し、該カウンタ値A n が前記閾値Thrをまたいだときにオン状態となり、該オン状態になってから設定時間経過後にオフ状態となる第1駆動信号を生成する第1駆動信号生成部20と、第1駆動信号に基づいて駆動された超音波振動子から超音波を送波させる送波部2と、を備えた超音波送波器10を構成する。 【選択図】図2
Abstract:
PROBLEM TO BE SOLVED: To provide an ultrasonic transmitter in a simple structure at high efficiency. SOLUTION: The ultrasonic transmitter is provided with a half bridge circuit provided with FET 1 and FET 2 on a driver circuit 12 for generating a drive pulse signal driving an oscillator 10, and inputs each drive signal from a driver I/F11 in FET 1 and FET 2 . In addition, drive voltage V B is supplied to a source terminal of FET 1 , a drain terminal of FET 2 is grounded, and an output terminal 51 of the half bridge circuit is connected to an oscillator 10. When FET 1 is on by performing control that any one of FET 1 and FET 2 is on, the drive voltage is supplied to the oscillator 10 as the drive pulse signal. When FET 2 is on, a closed loop circuit of low impedance is formed of the oscillator 10 and FET 2 . The oscillator 10 oscillates at a natural resonating frequency to transmit an ultrasonic signal by repeating them in a natural cycle. COPYRIGHT: (C)2005,JPO&NCIPI
Abstract:
The method and system uses ultrasound (US) transducers in contact with an inboard surface underwater portions of marine vessels or structures. By first digitally generating disruptive, multi-frequency, interfering US waveform signals (complex waveforms, typically replicating a Bessel function) and then converting the signals into analog, the transducers generate disruptive, multi-frequency, interfering US waveforms through the underwater portions of the marine vessels and structures which waveforms disrupt unwanted marine growth on the water-side of the vessel or structure. The digital signals, and also the analog signals, are complex waveform signals, typically produced with a Bessel function. The US transducers are either circular membrane transducers or surface transducers. A computer processor coupled to a memory, generates the complex waveform signals fed to the US transducers.
Abstract:
Systems and methods for the ultrasonic disruption of biofilm and algae growth on underwater structures utilize an ultrasonic actuator that produces a natural frequency in the ultrasonic range. In some embodiments, the ultrasonic actuator includes one or more piezoelectric transducers.
Abstract:
Techniques are disclosed for systems and methods to provide transmission signal shaping for transmission signal-based sensor systems, such as radar and/or sonar sensor systems. A low noise signal shaping transmitter includes a digital to analog converter configured to convert a digital shaping control signal to an analog shaping control signal, a signal shaping circuit configured to convert the analog shaping control signal into a shaped voltage, and a power amplifier configured to provide a shaped transmission signal based on the shaped voltage and a digital transmission control signal. Each element of the transmitter may be formed from relatively slow switching analog and/or digital circuitry components. Resulting shaped transmission signals may be used to excite radar antennas, sonar transducers, sound cells, and/or other elements of sensor systems.
Abstract:
A driver circuit for generating a driving pulse signal to activate a vibrating element includes a half-bridge circuit formed essentially of first and second switching devices to which drive signals are supplied through a driver interface. A driving voltage is supplied to a source of the first switching device, a drain of the second switching device is grounded, and an output terminal of the half-bridge circuit is connected to the vibrating element. The half-bridge circuit is controlled such that the two switching devices alternately turn ON. When the first switching device is ON, the driving voltage is supplied as the driving pulse signal to the vibrating element, and when the second switching device is ON, the vibrating element and the second switching device together form a low-impedance closed loop. As the switching devices are caused to alternately turn ON at specific intervals, the vibrating element vibrates at a natural resonant frequency, transmitting thereby an ultrasonic signal.