| 摘要 |
<p>A musical effect device receives an input signal from an electronic musical instrument or microphone. An effect control circuit coupled between the input and output applies a variable controllable effect to modify the input signal. The musical effect device further comprises a position sensor which senses a position of a moveable mechanical control and uses the result to determine the amount of controllable effect to apply to the input signal. The position sensor comprises: a first active tuned resonant LC circuit (29) such as a spiral coil track on a PCB; drive electronics to drive the circuit at a resonant frequency; and a second passive tuned resonant LC circuit (8, 9) associated with the moveable mechanical control. The resonant frequencies of the two LC circuits are matched; preferably the capacitance of at least one of the circuits is chosen so that their de-tuned resonant frequencies also match. The musical effect device may take the form of: an expression foot pedal (fig 5), a slider knob (fig 6), a rotary knob, or a wearable item (fig 7) such as jewellery or clothing. A position sensor, comprising one active resonant circuit and an electrically reactive element, is also claimed.</p> |
