| 摘要 |
The invention relates to circuits for ultrasonic transducers. In one embodiment the invention provides a parametric equalizer, suitable for use in an analogue circuit, characterised in that the parametric equalizer comprises a switching capacitor filter circuit; an oscillator wherein the oscillator controls the operation of the switching capacitor filter circuit. The oscillator is preferably a Voltage Controlled Oscillator (VCO). In a further embodiment the invention provides a circuit for use to condition the transmission and/or reception signals of an ultrasonic transducer, comprising an equivalent inductor circuit, for example a resonator circuit, having at least one operational amplifier; and a sliding rail element coupled to the operational amplifier.
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